iOS-Skill技巧

iOS开发

前言

iOS开发过程中，各种小问题，小技巧，代码片段， 在这里收集，写下，方便查阅，有时间会将其分类，并添加导航和标签。

PS:查找东西，现在只能用com+f,搜索关键字查找。。。
本文应该不在更新，或者说不在blog中更新了，有点麻烦，我会在Github中继续更新，链接地址

返回输入键盘

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<UITextFieldDelegate>

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    [textField resignFirstResponder];
    return YES;
}

CGRect

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CGRectFromString(<#NSString *string#>)//有字符串恢复出矩形
CGRectInset(<#CGRect rect#>, <#CGFloat dx#>, <#CGFloat dy#>)//创建较小或者较大的矩形
CGRectIntersectsRect(<#CGRect rect1#>, <#CGRect rect2#>)//判断两巨星是否交叉，是否重叠
CGRectZero//高度和宽度为零的，位于（0，0）的矩形常量

隐藏状态栏

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[UIApplication sharedApplication] setStatusBarHidden:<#(BOOL)#> withAnimation:<#(UIStatusBarAnimation)#>//隐藏状态栏

自动适应父视图大小

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self.view.autoresizesSubviews = YES;
    self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

UITableView的一些方法

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这里我自己做了个测试，缩进级别设置为行号，row越大，缩进越多
<UITableViewDelegate>

- (NSInteger)tableView:(UITableView *)tableView indentationLevelForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSInteger row = indexPath.row;
    return row;
}

把plist文件中的数据赋给数组

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NSString *path = [[NSBundle mainBundle] pathForResource:@"States" ofType:@"plist"];
NSArray *array = [NSArray arrayWithContentsOfFile:path];

获取触摸的点

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- (CGPoint)locationInView:(UIView *)view;
- (CGPoint)previousLocationInView:(UIView *)view;

获取触摸的属性

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@property(nonatomic,readonly) NSTimeInterval      timestamp;
@property(nonatomic,readonly) UITouchPhase        phase;
@property(nonatomic,readonly) NSUInteger          tapCount;

从plist中获取数据赋给字典

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NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"plist"];
NSDictionary *dictionary = [NSDictionary dictionaryWithContentsOfFile:plistPath];

NSUserDefaults注意事项

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设置完了以后如果存储的东西比较重要的话，一定要同步一下
[[NSUserDefaults standardUserDefaults] synchronize];

获取Documents目录

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NSString *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];

获取tmp目录

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NSString *tmpPath = NSTemporaryDirectory();

利用Safari打开一个链接

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NSURL *url = [NSURL URLWithString:@"http://baidu.com"];
[[UIApplication sharedApplication] openURL:url];

利用UIWebView显示pdf文件，网页等等

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<UIWebViewDelegate>

UIWebView *webView = [[UIWebView alloc]initWithFrame:self.view.bounds];
webView.delegate = self;
webView.scalesPageToFit = YES;
webView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[webView setAllowsInlineMediaPlayback:YES];
[self.view addSubview:webView];
    
NSString *pdfPath = [[NSBundle mainBundle] pathForResource:@"book" ofType:@"pdf"];
NSURL *url = [NSURL fileURLWithPath:pdfPath];
NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:(NSURLRequestUseProtocolCachePolicy) timeoutInterval:5];
[webView loadRequest:request];

UIWebView和html的简单交互

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myWebView = [[UIWebView alloc]initWithFrame:self.view.bounds];
[myWebView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]]];
NSError *error;
NSString *errorString = [NSString stringWithFormat:@"<html><center><font size=+5 color='red'>AnError Occurred;<br>%@</font></center></html>",error];
[myWebView loadHTMLString:errorString baseURL:nil];

//页面跳转了以后，停止载入
-(void)viewWillDisappear:(BOOL)animated {
    if (myWebView.isLoading) {
        [myWebView stopLoading];
    }
    myWebView.delegate = nil;
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}

汉字转码

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NSString *oriString = @"\u67aa\u738b";
NSString *escapedString = [oriString stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

处理键盘通知

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先注册通知，然后实现具体当键盘弹出来要做什么，键盘收起来要做什么
- (void)registerForKeyboardNotifications {
    keyboardShown = NO;//标记当前键盘是没有显示的
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasHidden:) name:UIKeyboardDidHideNotification object:nil];
}
//键盘显示要做什么
- (void)keyboardWasShown:(NSNotification *)notification {
    if (keyboardShown) {
        return;
    }
    NSDictionary *info = [notification userInfo];
    
    NSValue *aValue = [info objectForKey:UIKeyboardFrameBeginUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;
    CGRect viewFrame = scrollView.frame;
    viewFrame.size.height = keyboardSize.height;
    
    CGRect textFieldRect = activeField.frame;
    [scrollView scrollRectToVisible:textFieldRect animated:YES];
    keyboardShown = YES;
}

- (void)keyboardWasHidden:(NSNotification *)notification {
    NSDictionary *info = [notification userInfo];
    NSValue *aValue = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGSize keyboardSize = [aValue CGRectValue].size;
    
    CGRect viewFrame = scrollView.frame;
    viewFrame.size.height += keyboardSize.height;
    scrollView.frame = viewFrame;
    
    keyboardShown = NO;
}

点击键盘的next按钮，在不同的textField之间换行

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- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    
    if ([textField returnKeyType] != UIReturnKeyDone) {
        NSInteger nextTag = [textField tag] + 1;
        UIView *nextTextField = [self.tableView viewWithTag:nextTag];
        [nextTextField becomeFirstResponder];
    }else {
        [textField resignFirstResponder];
    }
    
    return YES;
}

设置日期格式

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dateFormatter = [[NSDateFormatter alloc]init];
dateFormatter.locale = [NSLocale currentLocale];
dateFormatter.calendar = [NSCalendar autoupdatingCurrentCalendar];
dateFormatter.timeZone = [NSTimeZone defaultTimeZone];
dateFormatter.dateStyle = NSDateFormatterShortStyle;
NSLog(@"%@",[dateFormatter stringFromDate:[NSDate date]]);

加载大量图片的时候，可以使用

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NSString *imagePath = [[NSBundle mainBundle] pathForResource:@"icon" ofType:@"png"];
UIImage *myImage = [UIImage imageWithContentsOfFile:imagePath];

有时候在iPhone游戏中，既要播放背景音乐，同时又要播放比如枪的开火音效。

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NSString *musicFilePath = [[NSBundle mainBundle] pathForResource:@"xx" ofType:@"wav"];
NSURL *musicURL = [NSURL fileURLWithPath:musicFilePath];
AVAudioPlayer *musicPlayer = [[AVAudioPlayer alloc]initWithContentsOfURL:musicURL error:nil];
[musicPlayer prepareToPlay];
musicPlayer.volume = 1;
musicPlayer.numberOfLoops = -1;//-1表示一直循环

从通讯录中读取电话号码，去掉数字之间的-

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NSString *originalString = @"(123)123123abc";
NSMutableString *strippedString = [NSMutableString stringWithCapacity:originalString.length];
NSScanner *scanner = [NSScanner scannerWithString:originalString];
NSCharacterSet *numbers = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];

    while ([scanner isAtEnd] == NO) {
        NSString *buffer;
        if ([scanner scanCharactersFromSet:numbers intoString:&buffer]) {
            [strippedString appendString:buffer];
        }else {
            scanner.scanLocation = [scanner scanLocation] + 1;
        }
    }
    NSLog(@"%@",strippedString);

字符串是否为空

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- (BOOL) isBlankString:(NSString *)string {
    if (string == nil || string == NULL) {
        return YES;
    }
    if ([string isKindOfClass:[NSNull class]]) {
        return YES;
    }
    if ([[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0) {
        return YES;
    }
    return NO;
}

正则判断：字符串只包含字母和数字

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NSString *myString = @"Letter1234";
NSString *regex = @"[a-z][A-Z][0-9]";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex];

    if ([predicate evaluateWithObject:myString]) {
        //implement
    }

设置UITableView的滚动条颜色

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self.tableView.indicatorStyle = UIScrollViewIndicatorStyleWhite;

网络编程

开发web等网络应用程序的时候，需要确认网络环境，连接情况等信息。如果没有处理它们，是不会通过apple的审查的。
系统自带的网络检查是原生的，AFNetworking也为我们添加了相关检测机制，所以这个直接在介绍AFNetworking的时候详解吧。

使用NSURLConnection下载数据

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1. 创建对象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]];
[NSURLConnection connectionWithRequest:request delegate:self];

2. NSURLConnection delegate 委托方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {

}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    
}

3. 实现委托方法
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    self.receiveData.length = 0;//先清空数据
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [self.receiveData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    //错误处理
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    NSString *returnString = [[NSString alloc]initWithData:self.receiveData encoding:NSUTF8StringEncoding];
    firstTimeDownloaded = YES;
}

隐藏状态栏

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[UIApplication sharedApplication].statusBarHidden = YES;

.m文件与.mm文件的区别

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.m文件是objective-c文件
.mm文件相当于c++或者c文件

Safari其实没有把内存的缓存写到存储卡上

读取一般性文件

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- (void)readFromTXT {
    NSString *tmp;
    NSArray *lines;//将文件转化为一行一行的
    lines = [[NSString stringWithContentsOfFile:@"testFileReadLines.txt"] componentsSeparatedByString:@"\n"];
    
    NSEnumerator *nse = [lines objectEnumerator];
    
    //读取<>里的内容
    while (tmp == [nse nextObject]) {
        NSString *stringBetweenBrackets = nil;
        NSScanner *scanner = [NSScanner scannerWithString:tmp];
        [scanner scanUpToString:@"<" intoString:nil];
        [scanner scanString:@"<" intoString:nil];
        [scanner scanUpToString:@">" intoString:&stringBetweenBrackets];
        NSLog(@"%@",[stringBetweenBrackets description]);
    }
}

隐藏UINavigationBar

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 [self.navigationController setNavigationBarHidden:YES animated:YES];

调用电话，短信，邮件

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[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"mailto:apple@mac.com?Subject=hello"]];
sms://调用短信
tel://调用电话
itms://打开MobileStore.app

获取版本信息

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UIDevice *myDevice = [UIDevice currentDevice];
NSString *systemVersion = myDevice.systemVersion;

UIWebView的使用

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<UIWebViewDelegate>

webView.delegate = self;

(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    NSURL *url = request.URL;
    NSString *urlStirng = url.absoluteString;
    NSLog(@"%@",urlStirng);
    return YES;
}

UIButton的title和image不能同时显示
UINavigationItem也是

不要再语言包里面设置空格

NSNotificationCenter带参数发送

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MPMoviePlayerController *theMovie = [[MPMoviePlayerController alloc]initWithContentURL:[NSURL fileURLWithPath:moviePath]];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myMovieFinishedCallback:) name:MPMoviePlayerPlaybackDidFinishNotification object:theMovie];
[theMovie play];

- (void)myMovieFinishedCallback:(NSNotification *)aNotification {
    MPMoviePlayerController *theMovie = [aNotification object];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerPlaybackDidFinishNotification object:theMovie];
}

延迟一段时间执行某个函数

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[self performSelector:@selector(dismissModal) withObject:self afterDelay:1.0];

用NSDateFormatter调整时间格式代码

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NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSString *currentDateStr = [dateFormatter stringFromDate:[NSDate date]];

UIView设置成圆角的方法

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mainView.layer.cornerRadius = 6;
mainView.layer.masksToBounds = YES;

Objective-C 内存管理

  1. 一个对象可以有一个或多个拥有者
  2. 当它一个拥有者都没有的时候，它就会被回收
  3. 如果想保留一个对象不被回收，你就必须成为它的拥有者

关键字

  1. alloc
    为对象分配内存，计数设为1，并返回此对象。
  • copy
    复制一个对象，此对象计数为1，返回此对象。你将成为此克隆对象的拥有者。
  • retain
    对象计数+1，并成为次对象的拥有者。
  • release
    对象计数-1，并丢掉此对象。
  • autorelease
    在未来的某一个时刻，对象计数-1。并在未来的某个时间放弃此对象。

原则

  1. 一个代码块内要确保copy，alloc 和 retain 的使用数量与 release 和 autorelease 的数量相等。
  • 在使用以 alloc 或 new 开头或包含 copy 的方法，或 retain 一个对象时，你将会编程它的拥有者。
  • 实现 dealloc 方法，这是系统当 retain -> 0 的时候，自动调用的。手动调用会引起 retain count 计数错误（多一次的 release）。

iPhone 更改键盘右下角按键的 type

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SearchBar *mySearchBar = [[UISearchBar alloc]init];
mySearchBar.frame = CGRectMake(0, 0, self.view.bounds.size.width, 44);
mySearchBar.placeholder = @"placeholderString";
mySearchBar.delegate = self;
[self.view addSubview:mySearchBar];
UITextField *searchField = [[mySearchBar subviews] lastObject];
searchField.returnKeyType = UIReturnKeyDone;

tableView左滑出多个按钮

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- (NSArray *)tableView:(UITableView *)tableView editActionsForRowAtIndexPath:(NSIndexPath *)indexPath
{
    //删除按钮
    UITableViewRowAction *deleteRowAction = [UITableViewRowAction rowActionWithStyle:UITableViewRowActionStyleDefault title:@"删除" handler:^(UITableViewRowAction * _Nonnull action, NSIndexPath * _Nonnull indexPath){
        [_dataArray removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:@[indexPath]withRowAnimation:UITableViewRowAnimationAutomatic];
    }];
     
 
    //置顶按钮
    UITableViewRowAction *toTopRowAction = [UITableViewRowAction rowActionWithStyle:UITableViewRowActionStyleDefault title:@"置顶" handler:^(UITableViewRowAction * _Nonnull action, NSIndexPath * _Nonnull indexPath){
         
        NSLog(@"置顶");
         
    }];
    toTopRowAction.backgroundColor = [UIColor orangeColor];
     
    //其他按钮
    UITableViewRowAction *otherRowAction = [UITableViewRowAction rowActionWithStyle:UITableViewRowActionStyleDefault title:@"其他" handler:^(UITableViewRowAction * _Nonnull action, NSIndexPath * _Nonnull indexPath){
        NSLog(@"其他");
    }];
 
    otherRowAction.backgroundColor = [UIColor lightGrayColor];
 
    //返回按钮数组
    return @[deleteRowAction, toTopRowAction, otherRowAction];
}

给图片增加模糊效果

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//加模糊效果，image是图片，blur是模糊度
+ (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {
    //模糊度,
    if ((blur < 0.1f) || (blur > 2.0f)) {
        blur = 0.1f;
    }
     
    //boxSize必须大于0
    int boxSize = (int)(blur * 100);
    boxSize -= (boxSize % 2) + 1;
    NSLog(@"boxSize:%i",boxSize);
    //图像处理
    CGImageRef img = image.CGImage;
     
    //图像缓存,输入缓存，输出缓存
    vImage_Buffer inBuffer, outBuffer;
    vImage_Error error;
    //像素缓存
    void *pixelBuffer;
     
    //数据源提供者，Defines an opaque type that supplies Quartz with data.
    CGDataProviderRef inProvider = CGImageGetDataProvider(img);
    // provider’s data.
    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);
     
    //宽，高，字节/行，data
    inBuffer.width = CGImageGetWidth(img);
    inBuffer.height = CGImageGetHeight(img);
    inBuffer.rowBytes = CGImageGetBytesPerRow(img);
    inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);
     
    //像数缓存，字节行*图片高
    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
     
    outBuffer.data = pixelBuffer;
    outBuffer.width = CGImageGetWidth(img);
    outBuffer.height = CGImageGetHeight(img);
    outBuffer.rowBytes = CGImageGetBytesPerRow(img);
     
     
    // 第三个中间的缓存区,抗锯齿的效果
    void *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));
    vImage_Buffer outBuffer2;
    outBuffer2.data = pixelBuffer2;
    outBuffer2.width = CGImageGetWidth(img);
    outBuffer2.height = CGImageGetHeight(img);
    outBuffer2.rowBytes = CGImageGetBytesPerRow(img);
     
    //Convolves a region of interest within an ARGB8888 source image by an implicit M x N kernel that has the effect of a box filter.
    error = vImageBoxConvolve_ARGB8888(&inBuffer;, &outBuffer2;, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    error = vImageBoxConvolve_ARGB8888(&outBuffer2;, &inBuffer;, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
    error = vImageBoxConvolve_ARGB8888(&inBuffer;, &outBuffer;, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);
     
     
    if (error) {
        NSLog(@"error from convolution %ld", error);
    }
     
    //    NSLog(@"字节组成部分：%zu",CGImageGetBitsPerComponent(img));
    //颜色空间DeviceRGB
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    //用图片创建上下文,CGImageGetBitsPerComponent(img),7,8
    CGContextRef ctx = CGBitmapContextCreate(
                                             outBuffer.data,
                                             outBuffer.width,
                                             outBuffer.height,
                                             8,
                                             outBuffer.rowBytes,
                                             colorSpace,
                                             CGImageGetBitmapInfo(image.CGImage));
     
    //根据上下文，处理过的图片，重新组件
    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
     
    //clean up
    CGContextRelease(ctx);
    CGColorSpaceRelease(colorSpace);
     
    free(pixelBuffer);
    free(pixelBuffer2);
    CFRelease(inBitmapData);
    CGImageRelease(imageRef);
     
    return returnImage;
}

网易新闻头部滚动切换

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- (void)titleButtonDidClick:(UIButton *)titleButton
{
    self.mainScrollView.contentOffset  = CGPointMake(kScreenWidth * titleButton.tag, 0);
    [UIView animateWithDuration:0.5 animations:^{
        if (self.titleScrollView.contentOffset.x >= 0) {
    self.titleScrollView.contentOffset = CGPointMake(titleButton.x - 150, 0);
        }
        // 先改变contentOffset，若偏移则修正
        if (self.titleScrollView.contentOffset.x <= 0) {
    self.titleScrollView.contentOffset = CGPointZero;
        }
        if (self.titleScrollView.contentOffset.x >= 2 * 900 - kScreenWidth) {
    self.titleScrollView.contentOffset = CGPointMake(2 * 900 - kScreenWidth, 0);
        }
    }];
}

七牛上传图片的简单封装

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#import "QiNiuTool.h"
#import "JKRAccountTool.h"
#import "JKRAccount.h"
#import "QiniuSDK.h"
#import "QiNiuUpLoadResult.h"
#import <UIKit/UIKit.h>
 
@implementation QiNiuTool
 
+ (void)uploadImages:(NSArray *)images complete:(void (^)(NSDictionary *))complete
{
    QNUploadManager *qnm = [[QNUploadManager alloc] init];
    NSDateFormatter *mattter = [[NSDateFormatter alloc]init];
    [mattter setDateFormat:@"yyyyMMddHHmmss"];
    NSString *Nowdate = [mattter stringFromDate:[NSDate date]];
     
    QiNiuUpLoadResult *result = [[QiNiuUpLoadResult alloc] init];
     
    __block int count = 0;
     
    for (int i = 0; i < images.count; i++) {
         
        UIImage *image = images[i];
         
        NSData *uploadData = UIImageJPEGRepresentation(image, 1);
         
        //这里对大图片做了压缩，不需要的话下面直接传uploadData就好
        NSData *cutdownData = nil;
        if (uploadData.length < 9999) {
            cutdownData = UIImageJPEGRepresentation(image, 1.0);
        } else if (uploadData.length < 99999) {
            cutdownData = UIImageJPEGRepresentation(image, 0.6);
        } else {
            cutdownData = UIImageJPEGRepresentation(image, 0.3);
        }
         
        //[JKRAccountTool getAccount].token:token
        [qnm putData:cutdownData key:[NSString stringWithFormat:@"%@%d", Nowdate, i+1] token:[JKRAccountTool getAccount].token complete:^(QNResponseInfo *info, NSString *key, NSDictionary *resp) {
             
            count++;
             
            NSString *resultKey = [NSString stringWithFormat:@"%d",i];
             
            result.keys[resultKey] = [resp objectForKey:@"key"];
             
            if (count == images.count) {
                complete(result.keys);
            }
             
        } option:nil];
         
    }
     
}
 
@end

导航条渐隐渐现

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[_tableView addObserver: self forKeyPath: @"contentOffset" options: NSKeyValueObservingOptionNew context:nil];
 
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context{
    CGFloat offset=_tableView.contentOffset.y;
    NSLog(@"offset:%f",offset);//越来越大  想要实现效果：一开始全显示，后来颜色变浅
    CGFloat delta=1-offset/100.f;
    delta=MIN(1,delta);
    NSLog(@"%f",delta);
    self.navigationController.navigationBar.alpha=MIN(1,delta);
 
}

图片压缩

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用法：UIImage *yourImage= [self imageWithImageSimple:image scaledToSize:CGSizeMake(210.0, 210.0)];
//压缩图片
- (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize
{
// Create a graphics image context
UIGraphicsBeginImageContext(newSize);
// Tell the old image to draw in this newcontext, with the desired
// new size
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
// Get the new image from the context
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
// End the context
UIGraphicsEndImageContext();
// Return the new image.
return newImage;
}

图片裁剪，类似新浪微博小图显示效果

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CGSize asize = CGSizeMake(300, 300);
    UIImage *newimage;
    UIImage *image = [UIImage imageNamed:@""];
    if (nil == image) {
        newimage = nil;
    }
    else{
        CGSize oldsize = image.size;
        CGRect rect;
        if (asize.width/asize.height > oldsize.width/oldsize.height) {
            rect.size.width = asize.width;
            rect.size.height = asize.width*oldsize.height/oldsize.width;
            rect.origin.x = 0;
            rect.origin.y = (asize.height - rect.size.height)/2;
        }
        else{
            rect.size.width = asize.height*oldsize.width/oldsize.height;
            rect.size.height = asize.height;
            rect.origin.x = (asize.width - rect.size.width)/2;
            rect.origin.y = 0;
        }
        UIGraphicsBeginImageContext(asize);
        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextClipToRect(context, CGRectMake(0, 0, asize.width, asize.height));
        CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
        UIRectFill(CGRectMake(0, 0, asize.width, asize.height));//clear background
        [image drawInRect:rect];
        newimage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    }
     
    UIImageView * imgView = [[UIImageView alloc]initWithFrame:CGRectMake(10, 10, 100, 100)];
    imgView.image = newimage;
    [self.view addSubview:imgView];

把时间戳转换为时间

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+ (NSDate *)dateWithTimeIntervalInMilliSecondSince1970:(double)timeIntervalInMilliSecond {
    NSDate *ret = nil;
    double timeInterval = timeIntervalInMilliSecond;
    // judge if the argument is in secconds(for former data structure).
    if(timeIntervalInMilliSecond > 140000000000) {
        timeInterval = timeIntervalInMilliSecond / 1000;
    }
    ret = [NSDate dateWithTimeIntervalSince1970:timeInterval];
     
    return ret;
}

自定义cell中获取不到cell实际大小的办法

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-(void)drawRect:(CGRect)rect {
    // 重写此方法，并在此方法中获取
    CGFloat width = self.frame.size.width;
}

长按图标抖动

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-(void)longPress:(UILongPressGestureRecognizer*)longPress
{
    if (longPress.state==UIGestureRecognizerStateBegan) {
        CAKeyframeAnimation* anim=[CAKeyframeAnimation animation];
        anim.keyPath=@"transform.rotation";
        anim.values=@[@(angelToRandian(-7)),@(angelToRandian(7)),@(angelToRandian(-7))];
        anim.repeatCount=MAXFLOAT;
        anim.duration=0.2;
        [self.imageView.layer addAnimation:anim forKey:nil];
        self.btn.hidden=NO;
    }
}

阿拉伯数字转化为汉语数字

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+(NSString *)translation:(NSString *)arebic
 
{   NSString *str = arebic;
    NSArray *arabic_numerals = @[@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"0"];
    NSArray *chinese_numerals = @[@"一",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"零"];
    NSArray *digits = @[@"个",@"十",@"百",@"千",@"万",@"十",@"百",@"千",@"亿",@"十",@"百",@"千",@"兆"];
    NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:chinese_numerals forKeys:arabic_numerals];
     
    NSMutableArray *sums = [NSMutableArray array];
    for (int i = 0; i < str.length; i ++) {
        NSString *substr = [str substringWithRange:NSMakeRange(i, 1)];
        NSString *a = [dictionary objectForKey:substr];
        NSString *b = digits[str.length -i-1];
        NSString *sum = [a stringByAppendingString:b];
        if ([a isEqualToString:chinese_numerals[9]])
        {
            if([b isEqualToString:digits[4]] || [b isEqualToString:digits[8]])
            {
                sum = b;
                if ([[sums lastObject] isEqualToString:chinese_numerals[9]])
                {
                    [sums removeLastObject];
                }
            }else
            {
                sum = chinese_numerals[9];
            }
             
            if ([[sums lastObject] isEqualToString:sum])
            {
                continue;
            }
        }
         
        [sums addObject:sum];
    }
     
    NSString *sumStr = [sums  componentsJoinedByString:@""];
    NSString *chinese = [sumStr substringToIndex:sumStr.length-1];
    NSLog(@"%@",str);
    NSLog(@"%@",chinese);
    return chinese;
}

两种方法删除NSUserDefaults所有记录

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//方法一
NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];
 
//方法二
- (void)resetDefaults {
    NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
    NSDictionary * dict = [defs dictionaryRepresentation];
    for (id key in dict) {
        [defs removeObjectForKey:key];
    }
    [defs synchronize];
}

截屏 全图

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- (UIImage *)imageFromView: (UIView *) theView
{
     
    UIGraphicsBeginImageContext(theView.frame.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [theView.layer renderInContext:context];
    UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
     
    return theImage;
}

判断是否用户开启了定位服务

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if ([CLLocationManager locationServicesEnabled] &&  
                ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusAuthorized  
                || [CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined)) {  
                //定位功能可用，开始定位  
                _locationManger = [[CLLocationManager alloc] init];  
                locationManger.delegate = self;  
                [locationManger startUpdatingLocation];  
            }  
            else if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusDenied){  
        NSlog("定位功能不可用，提示用户或忽略");   
            }

图片旋转

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UIImage * image = [UIImage imageNamed:@"iphone.png"];
NSData * tempData;
if (UIImagePNGRepresentation(image)) {
    tempData = UIImagePNGRepresentation(image);
    NSLog(@"%@",tempData);
}
else{
    tempData = UIImageJPEGRepresentation(image, 1);
}
CIImage * iImg = [CIImage imageWithData:tempData];
UIImage * tImg = [UIImage imageWithCIImage:iImg scale:1 orientation:UIImageOrientationRight];
NSLog(@"%@",UIImagePNGRepresentation(tImg));
UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake(10, 200, 200, 80)];
imageView.image = tImg;
[self.view addSubview:imageView];

去除UIImageView锯齿

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imageView.layer.shouldRasterize = YES;

判断两个日期之间的间隔

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NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyyMMddHHmmss"];
NSDate* toDate     = [dateFormatter dateFromString:@"19700608142033"];
NSDate*  startDate    = [ [ NSDate alloc] init ];
NSCalendar* chineseClendar = [ [ NSCalendar alloc ] initWithCalendarIdentifier:NSGregorianCalendar ];
NSUInteger unitFlags = NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit | NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit;
 
NSDateComponents *cps = [ chineseClendar components:unitFlags fromDate:startDate  toDate:toDate  options:0];
 
NSInteger diffYear = [cps year];
NSInteger diffMon = [cps month];
NSInteger diffDay = [cps day];
NSInteger diffHour = [cps hour];
NSInteger diffMin = [cps minute];
NSInteger diffSec = [cps second];
 
NSLog(@" From Now to %@, diff: Years: %d  Months: %d, Days; %d, Hours: %d, Mins:%d, sec:%d", [toDate description], diffYear, diffMon, diffDay, diffHour, diffMin,diffSec );

类似微信发送视频的流程

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//获取视频的本地url或者path，对视频进行获取第一帧图片，然后初始化消息的Model，设置封面

NSString *mediaType = [editingInfo objectForKey: UIImagePickerControllerMediaType];
                NSString *videoPath;
                NSURL *videoUrl;
                if (CFStringCompare ((__bridge CFStringRef) mediaType, kUTTypeMovie, 0) == kCFCompareEqualTo) {
                    videoUrl = (NSURL*)[editingInfo objectForKey:UIImagePickerControllerMediaURL];
                    videoPath = [videoUrl path];
                     
                    AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:videoUrl options:nil];
                    NSParameterAssert(asset);
                    AVAssetImageGenerator *assetImageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
                    assetImageGenerator.appliesPreferredTrackTransform = YES;
                    assetImageGenerator.apertureMode = AVAssetImageGeneratorApertureModeEncodedPixels;
                     
                    CGImageRef thumbnailImageRef = NULL;
                    CFTimeInterval thumbnailImageTime = 0;
                    NSError *thumbnailImageGenerationError = nil;
                    thumbnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumbnailImageTime, 60) actualTime:NULL error:&thumbnailImageGenerationError;];
                     
                    if (!thumbnailImageRef)
                        NSLog(@"thumbnailImageGenerationError %@", thumbnailImageGenerationError);
                     
                    UIImage *thumbnailImage = thumbnailImageRef ? [[UIImage alloc] initWithCGImage:thumbnailImageRef] : nil;
                     
                    XHMessage *videoMessage = [[XHMessage alloc] initWithVideoConverPhoto:thumbnailImage videoPath:videoPath videoUrl:nil sender:@"Jack" timestamp:[NSDate date]];
                    [weakSelf addMessage:videoMessage];
                }

刷新某行cell的方法

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//有时候只需要刷新某行的cell的数据，完全没必要调用[tableView reloadData]刷新整个列表的数据，调用以下方法即可。

NSIndexPath *indexPath_1=[NSIndexPath indexPathForRow:1 inSection:0];
      NSArray *indexArray=[NSArray  arrayWithObject:indexPath_1];
      [myTableView  reloadRowsAtIndexPaths:indexArray withRowAnimation:UITableViewRowAnimationAutomatic];

由身份证号码返回性别

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-(NSString *)sexStrFromIdentityCard:(NSString *)numberStr{
    NSString *result = nil;
     
    BOOL isAllNumber = YES;
     
    if([numberStr length]<17)
        return result;
     
    //**截取第17为性别识别符
    NSString *fontNumer = [numberStr substringWithRange:NSMakeRange(16, 1)];
     
    //**检测是否是数字;
    const char *str = [fontNumer UTF8String];
    const char *p = str;
    while (*p!='\0') {
        if(!(*p>='0'&&*p<='9'))
            isAllNumber = NO;
        p++;
    }
     
    if(!isAllNumber)
        return result;
     
    int sexNumber = [fontNumer integerValue];
    if(sexNumber%2==1)
        result = @"男";
    ///result = @"M";
    else if (sexNumber%2==0)
        result = @"女";
    //result = @"F";
     
    return result;
     
     
}

数组随机重新排列

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+ (NSArray *)getRandomWithPosition:(NSInteger)position positionContent:(id)positionContent array:(NSArray *)baseArray {
    NSMutableArray *resultArray = [NSMutableArray arrayWithCapacity:baseArray.count];
    NSMutableArray *tempBaseArray = [NSMutableArray arrayWithArray:baseArray];
     
    while ([tempBaseArray count]) {
        NSInteger range = [tempBaseArray count];
        id string = [tempBaseArray objectAtIndex:arc4random()%range];
        [resultArray addObject:string];
        [tempBaseArray removeObject:string];
    }
     
    NSUInteger index = [resultArray indexOfObject:positionContent];
    [resultArray exchangeObjectAtIndex:index withObjectAtIndex:position - 1];
     
    return resultArray;
}

利用陀螺仪实现更真实的微信摇一摇动画

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- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{    
    //想摇你的手机嘛？就写在这，然后，然后，没有然后了
    application.applicationSupportsShakeToEdit=YES;
}
 
-(void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if(motion==UIEventSubtypeMotionShake) {
         // 真实一点的摇动动画
        [self addAnimations];
         // 播放声音
        AudioServicesPlaySystemSound (soundID); 
    }
}
 
- (void)addAnimations {
    CABasicAnimation *translation = [CABasicAnimation animationWithKeyPath:@"transform"];
    translation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    translation.toValue=[NSValue valueWithCATransform3D:CATransform3DMakeRotation(-M_PI_4, 0, 0, 100)];
    translation.duration = 0.2;
    translation.repeatCount = 2;
    translation.autoreverses = YES;
     
    [shake.layer addAnimation:translation forKey:@"translation"];
}

GIF图片解析

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+ (NSMutableArray *)praseGIFDataToImageArray:(NSData *)data;
 {
    NSMutableArray *frames = [[NSMutableArray alloc] init];
    CGImageSourceRef src = CGImageSourceCreateWithData((CFDataRef)data, NULL);
    CGFloat animationTime = 0.f;
    if (src) {
        size_t l = CGImageSourceGetCount(src);
        frames = [NSMutableArray arrayWithCapacity:l];
        for (size_t i = 0; i < l; i++) {
            CGImageRef img = CGImageSourceCreateImageAtIndex(src, i, NULL);
            NSDictionary *properties = (NSDictionary *)CGImageSourceCopyPropertiesAtIndex(src, i, NULL);
            NSDictionary *frameProperties = [properties objectForKey:(NSString *)kCGImagePropertyGIFDictionary];
            NSNumber *delayTime = [frameProperties objectForKey:(NSString *)kCGImagePropertyGIFUnclampedDelayTime];
            animationTime += [delayTime floatValue];
            if (img) {
                [frames addObject:[UIImage imageWithCGImage:img]];
                CGImageRelease(img);
            }
        }
        CFRelease(src);
    }
     return frames;
}

在后台播放音乐

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//1. 在Info.plist中，添加"Required background modes"键，其值设置是“App plays audio" 
//2. 在播放器播放音乐的代码所在处，添加如下两段代码（当然，前提是已经添加了AVFoundation框架）

//添加后台播放代码：
AVAudioSession *session = [AVAudioSession sharedInstance];    
[session setActive:YES error:nil];    
[session setCategory:AVAudioSessionCategoryPlayback error:nil];   
 
//以及设置app支持接受远程控制事件代码。设置app支持接受远程控制事件，
//其实就是在dock中可以显示应用程序图标，同时点击该图片时，打开app。
//或者锁屏时，双击home键，屏幕上方出现应用程序播放控制按钮。
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents]; 
 
 
//用下列代码播放音乐，测试后台播放
// 创建播放器  
AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];  
[url release];  
[player prepareToPlay];  
[player setVolume:1];  
player.numberOfLoops = -1; //设置音乐播放次数  -1为一直循环  
[player play]; //播放

本文标题:iOS-Skill技巧

文章作者:Yi'mouleng

发布时间:2014年04月23日 - 00时00分

最后更新:2016年01月28日 - 17时58分

原始链接:http://yimouleng.github.io/2014/04/23/ios-skill/

许可协议: "署名-非商用-相同方式共享 3.0" 转载请保留原文链接及作者。

文章目录
  1. 1. 前言
    1. 1.0.1. 返回输入键盘
    2. 1.0.2. CGRect
    3. 1.0.3. 隐藏状态栏
    4. 1.0.4. 自动适应父视图大小
    5. 1.0.5. UITableView的一些方法
    6. 1.0.6. 把plist文件中的数据赋给数组
    7. 1.0.7. 获取触摸的点
    8. 1.0.8. 获取触摸的属性
    9. 1.0.9. 从plist中获取数据赋给字典
    10. 1.0.10. NSUserDefaults注意事项
    11. 1.0.11. 获取Documents目录
    12. 1.0.12. 获取tmp目录
    13. 1.0.13. 利用Safari打开一个链接
    14. 1.0.14. 利用UIWebView显示pdf文件，网页等等
    15. 1.0.15. UIWebView和html的简单交互
    16. 1.0.16. 汉字转码
    17. 1.0.17. 处理键盘通知
    18. 1.0.18. 点击键盘的next按钮，在不同的textField之间换行
    19. 1.0.19. 设置日期格式
    20. 1.0.20. 加载大量图片的时候，可以使用
    21. 1.0.21. 有时候在iPhone游戏中，既要播放背景音乐，同时又要播放比如枪的开火音效。
    22. 1.0.22. 从通讯录中读取电话号码，去掉数字之间的-
    23. 1.0.23. 字符串是否为空
    24. 1.0.24. 正则判断：字符串只包含字母和数字
    25. 1.0.25. 设置UITableView的滚动条颜色
    26. 1.0.26. 网络编程
    27. 1.0.27. 使用NSURLConnection下载数据
    28. 1.0.28. 隐藏状态栏
    29. 1.0.29. .m文件与.mm文件的区别
    30. 1.0.30. Safari其实没有把内存的缓存写到存储卡上
    31. 1.0.31. 读取一般性文件
    32. 1.0.32. 隐藏UINavigationBar
    33. 1.0.33. 调用电话，短信，邮件
    34. 1.0.34. 获取版本信息
    35. 1.0.35. UIWebView的使用
    36. 1.0.36. NSNotificationCenter带参数发送
    37. 1.0.37. 延迟一段时间执行某个函数
    38. 1.0.38. 用NSDateFormatter调整时间格式代码
    39. 1.0.39. UIView设置成圆角的方法
    40. 1.0.40. Objective-C 内存管理
    41. 1.0.41. 关键字
    42. 1.0.42. 原则
    43. 1.0.43. iPhone 更改键盘右下角按键的 type
    44. 1.0.44. tableView左滑出多个按钮
    45. 1.0.45. 给图片增加模糊效果
    46. 1.0.46. 网易新闻头部滚动切换
    47. 1.0.47. 七牛上传图片的简单封装
    48. 1.0.48. 导航条渐隐渐现
    49. 1.0.49. 图片压缩
    50. 1.0.50. 图片裁剪，类似新浪微博小图显示效果
    51. 1.0.51. 把时间戳转换为时间
    52. 1.0.52. 自定义cell中获取不到cell实际大小的办法
    53. 1.0.53. 长按图标抖动
    54. 1.0.54. 阿拉伯数字转化为汉语数字
    55. 1.0.55. 两种方法删除NSUserDefaults所有记录
    56. 1.0.56. 截屏 全图
    57. 1.0.57. 判断是否用户开启了定位服务
    58. 1.0.58. 图片旋转
    59. 1.0.59. 去除UIImageView锯齿
    60. 1.0.60. 判断两个日期之间的间隔
    61. 1.0.61. 类似微信发送视频的流程
    62. 1.0.62. 刷新某行cell的方法
    63. 1.0.63. 由身份证号码返回性别
    64. 1.0.64. 数组随机重新排列
    65. 1.0.65. 利用陀螺仪实现更真实的微信摇一摇动画
    66. 1.0.66. GIF图片解析
    67. 1.0.67. 在后台播放音乐