iOS开发中一些有用的小代码（持续更新)

1.判断邮箱格式是否正确的代码：

// 利用正则表达式验证

-( BOOL )isValidateEmail:( NSString  *)email

{

NSString  *emailRegex =  @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}" ;

NSPredicate  *emailTest = [ NSPredicate   predicateWithFormat : @"SELF MATCHES%@",emailRegex];

return  [emailTest  evaluateWithObject :email];

}

 

2.图片压缩

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;

}

 

3.亲测可用的图片上传代码

- ( IBAction )uploadButton:( id )sender {

UIImage  *image = [ UIImage   imageNamed : @"1.jpg" ]; // 图片名

NSData  *imageData =  UIImageJPEGRepresentation (image, 0.5 );// 压缩比例

NSLog ( @" 字节数 :%i" ,[imageData length]);

// post url

NSString  *urlString =  @"http://192.168.1.113:8090/text/UploadServlet" ;

// 服务器地址

// setting up the request object now

NSMutableURLRequest  *request = [[ NSMutableURLRequest   alloc ]  init ] ;

[request  setURL :[ NSURL   URLWithString :urlString]];

[request  setHTTPMethod : @"POST" ];

//

NSString  *boundary = [ NSString   stringWithString : @"---------------------------14737809831466499882746641449" ];

NSString  *contentType = [ NSString   stringWithFormat : @"multipart/form-data;boundary=%@",boundary];

[request  addValue :contentType  forHTTPHeaderField :  @"Content-Type" ];

//

NSMutableData  *body = [ NSMutableData   data ];

[body  appendData :[[ NSString   stringWithFormat : @"\r\n--%@\r\n" ,boundary] dataUsingEncoding : NSUTF8StringEncoding ]];

[body  appendData :[[ NSString   stringWithString : @"Content-Disposition:form-data; name=\"userfile\"; filename=\"2.png\"\r\n" ]  dataUsingEncoding : NSUTF8StringEncoding ]]; // 上传上去的图片名字

[body  appendData :[[ NSString   stringWithString : @"Content-Type: application/octet-stream\r\n\r\n" ]  dataUsingEncoding : NSUTF8StringEncoding ]];

[body  appendData :[ NSData   dataWithData :imageData]];

[body  appendData :[[ NSString   stringWithFormat : @"\r\n--%@--\r\n" ,boundary] dataUsingEncoding : NSUTF8StringEncoding ]];

  [request  setHTTPBody :body];

// NSLog(@"1-body:%@",body);

NSLog ( @"2-request:%@" ,request);

NSData  *returnData = [ NSURLConnection   sendSynchronousRequest :request  returningResponse :nil   error : nil ];

NSString  *returnString = [[ NSString   alloc ]  initWithData :returnData  encoding :NSUTF8StringEncoding ];

NSLog ( @"3- 测试输出： %@" ,returnString );

 

4.给imageView加载图片

UIImage  *myImage = [ UIImage   imageNamed : @"1.jpg" ];

   [ imageView   setImage :myImage];

   [ self . view   addSubview : imageView ];

 

5.对图库的操作

选择相册：

UIImagePickerControllerSourceTypesourceType=UIImagePickerControllerSourceTypeCamera;

   if (![UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {

       sourceType=UIImagePickerControllerSourceTypePhotoLibrary;

   }

   UIImagePickerController * picker = [[UIImagePickerControlleralloc]init];

   picker.delegate = self;

   picker.allowsEditing=YES;

   picker.sourceType=sourceType;

   [self presentModalViewController:picker animated:YES];

选择完毕：

 -(void)imagePickerController:(UIImagePickerController*)pickerdidFinishPickingMediaWithInfo:(NSDictionary *)info

{

   [picker dismissModalViewControllerAnimated:YES];

   UIImage * image=[info objectForKey:UIImagePickerControllerEditedImage];

   [self performSelector:@selector(selectPic:) withObject:imageafterDelay:0.1];

}

 -(void)selectPic:(UIImage*)image

{

   NSLog(@"image%@",image); 

   imageView = [[UIImageView alloc] initWithImage:image];

   imageView.frame = CGRectMake(0, 0, image.size.width, image.size.height);

[self.viewaddSubview:imageView];

   [self performSelectorInBackground:@selector(detect:) withObject:nil];

}

detect 为自己定义的方法，编辑选取照片后要实现的效果

取消选择：

 -(void)imagePickerControllerDIdCancel:(UIImagePickerController*)picker 

{

   [picker dismissModalViewControllerAnimated:YES];

}

 

6.跳到下个View

nextWebView  = [[ WEBViewController   alloc ]  initWithNibName : @"WEBViewController"   bundle :nil ];

[ self   presentModalViewController : nextWebView   animated : YES ];

7.创建一个UIBarButton右边按钮

UIBarButtonItem  *rightButton = [[ UIBarButtonItem   alloc ]  initWithTitle : @" 右边 "   style :UIBarButtonItemStyleDone   target : self   action : @selector (clickRightButton)];

[ self . navigationItem   setRightBarButtonItem :rightButton];

 

8.设置navigationBar隐藏

self . navigationController . navigationBarHidden  =  YES ;//

 

9.UIlabel多行文字自动换行 （自动折行）

UIView *footerView = [[UIView alloc]initWithFrame:CGRectMake(10, 100, 300, 180)];

UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(10, 100, 300, 150)];

label.text = @"Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Helloworld!";

// 背景颜色为红色

label.backgroundColor = [UIColor redColor];

// 设置字体颜色为白色

label.textColor = [UIColor whiteColor];

// 文字居中显示

label.textAlignment = UITextAlignmentCenter;

// 自动折行设置

label.lineBreakMode = UILineBreakModeWordWrap;

label.numberOfLines = 0;

 

10.代码生成Button

CGRect  frame =  CGRectMake ( 0 ,  400 ,  72.0 ,  37.0 );

UIButton  *button = [ UIButton   buttonWithType : UIButtonTypeRoundedRect ];

button. frame  = frame;

[button  setTitle : @" 新添加的按钮 "  forState:  UIControlStateNormal ];

button. backgroundColor  = [ UIColor   clearColor ];

button. tag  =  2000 ;

[button  addTarget : self   action : @selector (buttonClicked:)  forControlEvents :UIControlEventTouchUpInside ];

[ self . view   addSubview :button];

 

10.2在xib文件中已经创建好Button，通过tag获取按钮 

UIButton *testButton= (UIButton*)[self.view viewWithTag:100];
    [testButton addTarget:self action:@selector(test:) forControlEvents:UIControlEventTouchUpInside];

  //按钮事件

-(void) test: (id) sender{
    UIAlertView *av = [[[UIAlertView alloc] initWithTitle:@"ceshi" message:@"test11111" delegate:nil cancelButtonTitle:@"OK"otherButtonTitles:nil] autorelease];
    [av show];
}

11.让某个控件在View的中心位置显示：

（某个控件，比如 label ， View ） label . center  =  self . view . center；

 

12.自定义text各种效果：

cell.backgroundColor = [UIColorscrollViewTexturedBackgroundColor];
// 设置文字的字体 
cell.textLabel.font = [UIFont fontWithName:@"AmericanTypewriter" size:100.0f];
// 设置文字的颜色 
cell.textLabel.textColor = [UIColor orangeColor];
// 设置文字的背景颜色 
cell.textLabel.shadowColor = [UIColor whiteColor];
// 设置文字的显示位置 
cell.textLabel.textAlignment = UITextAlignmentCenter;

 

13.隐藏statusBar： 
在程序的 viewDidLoad 中加入 

[[UIApplication sharedApplication]setStatusBarHidden:YES animated:NO];

 

14.更改AlertView背景：
UIAlertView *theAlert = [[[UIAlertViewalloc] initWithTitle:@"Atention" 
                                                     message: @"I'm a Chinese!" 
                                                    delegate:nil  
                                            cancelButtonTitle:@"Cancel"  
                                            otherButtonTitles:@"Okay",nil] autorelease]; 
   [theAlert show]; 
   UIImage *theImage = [UIImageimageNamed:@"loveChina.png"];    
   theImage = [theImage stretchableImageWithLeftCapWidth:0topCapHeight:0]; 
   CGSize theSize = [theAlert frame].size; 
    UIGraphicsBeginImageContext(theSize);     
   [theImage drawInRect:CGRectMake(5, 5, theSize.width-10, theSize.height-20)];// 这个地方的大小要自己调整，以适应 alertview 的背景颜色的大小。 
   theImage = UIGraphicsGetImageFromCurrentImageContext();    
UIGraphicsEndImageContext(); 
   theAlert.layer.contents = (id)[theImage CGImage];

 

15.键盘透明： 
textField.keyboardAppearance = UIKeyboardAppearanceAlert;

16.状态栏的网络活动风火轮是否旋转： 
[UIApplication sharedApplication].networkActivityIndicatorVisible ， 默认值是 NO 。

 

17.截取屏幕图片： 
// 创建一个基于位 图的图形上下文并指定大小为CGSizeMake(200,400)
UIGraphicsBeginImageContext(CGSizeMake(200,400)); 

//renderInContext  呈现接受者及其子范围到 指定的上下文
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    // 返回 一个基于当前图形上下文的图片
 UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();
  // 移除栈顶 的基于当前位图的图形上下文
UIGraphicsEndImageContext();
// 以 png 格式 返回指定图片的数据
imageData = UIImagePNGR epresentation(aImage);

 

18.更改cell选中的背景： 
    UIView *myview = [[UIView alloc] init];
    myview.frame = CGRectMake(0, 0, 320, 47);
    myview.backgroundColor = [UIColorcolorWithPatternImage:[UIImage imageNamed:@"0006.png"]];
    cell.selectedBackgroundView = myview;:

19.显示图片：

CGRect myImageRect = CGRectMake(0.0f, 0.0f, 320.0f, 109.0f); 
UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect];
[myImage setImage:[UIImage imageNamed:@"myImage.png"]]; 
myImage.opaque = YES; //opaque 是否透明
[self.view addSubview:myImage];

 

20.能让图片适应框的大小（beta）

NSString*imagePath = [[NSBundle mainBundle] pathForResource:@"XcodeCrash"ofType:@"png"];     
    UIImage *image = [[UIImage alloc]initWithContentsOfFile:imagePath]; 
        UIImage *newImage= [image transformWidth:80.f height:240.f]; 
    UIImageView *imageView = [[UIImageView alloc]initWithImage: newImage]; 
         [newImagerelease]; 
    [image release]; 
    [self.view addSubview:imageView];

 

21. 实现点击图片进行跳转的代码：（生成一个带有背景图片的button，给button绑定想要的事件）

UIButton *imgButton=[[UIButton alloc]initWithFrame:CGRectMake(0, 0, 120, 120)];

[imgButton setBackgroundImage:(UIImage *)[self.imgArray objectAtIndex:indexPath.row] forState:UIControlStateNormal];

imgButton.tag=[indexPath row];

[imgButton addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];

 

22.键盘回收：

1).增加一个button，相应touch down事件，隐藏键盘。这种方法，太山寨了。为了相应一个事件增加一个button太不值得的。

.h

- (IBAction)dismissKeyBoard:(id)sender;

.m

- (IBAction)dismissKeyBoard:(id)sender {

    [testText resignFirstResponder];

}

2).第二种方法：在背景图片上添加Tap事件，相应单击处理。这种方法，很好代替了button方式，但是如果UI上没有背景图片，这种方法又回到到第一种山寨的方法行列中。

// 添加带有处理时间的背景图片

    UIImageView *backView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];

    backView.image = [UIImage imageNamed:@"small3.png"];

    

    backView.userInteractionEnabled = YES;

    UITapGestureRecognizer *singleTouch = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissKeyboard:)];

    [backView addGestureRecognizer:singleTouch];

    

    backView.tag = 110;

    [self.view addSubview:backView];

-(void)dismissKeyboard:(id)sender{

    [text resignFirstResponder];

}

3).在xib文件中，修改xib文件的objects属性，默认是view属性，我们可以修改为UIControl属性，从而是xib文件相应touch down事件。这种方法，缺点就是没有xib就悲剧了。

.h

- (IBAction)dimissKeyboard:(id)sender;

.m

- (IBAction)dimissKeyboard:(id)sender {

    [text resignFirstResponder];

}

23、Gif图片的解析

01//加载gif

02 

03  NSString *filePath = [[NSBundle mainBundle]pathForResource:@"bai3" ofType:@"gif"];

04 

05    NSData *data = [NSData dataWithContentsOfFile:filePath];

06 

07    CGImageSourceRef gif = CGImageSourceCreateWithData((CFDataRef)data, nil);

08 

09 //获取gif的各种属性

10 

11    CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,0,NULL));

12 

13    NSLog(@"_______%@",gifprops);

14 

15 

16    NSInteger count =CGImageSourceGetCount(gif);

17 

18    NSLog(@"________%d",count);

19 

20 

21   CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);

22 

23 CFDictionaryRef delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);

24 

25    NSLog(@"_______%@",delay);

26 

27 

28 //[gifDic objectForKey:(NSString *)kCGImagePropertyGIFDelayTime];

29 

30    //    NSNumber * w = CFDictionaryGetValue(gifprops, @"PixelWidth");

31 

32    //    NSNumber * h =CFDictionaryGetValue(gifprops, @"PixelHeight");

33 

34    //    float totalDuration = delay.doubleValue * count;

35 

36    //    float pixelWidth = w.intValue;

37 

38    //    float pixelHeight = h.intValue;

39 

40  //将gif解析成UIImage类型对象，并加进images数组中 

41 

42 

43    NSMutableArray *images = [NSMutableArray arrayWithCapacity:count];

44 

45    for(int index=0;index<count;index++)

46 

47    {

48 

49        CGImageRef ref = CGImageSourceCreateImageAtIndex(gif, index, nil);

50 

51        UIImage *img = [UIImage imageWithCGImage:ref];

52 

53        [images addObject:img];

54 

55        CFRelease(ref);

56 

57    }

58 

59    CFRelease(gifprops);

60 

61    CFRelease(gif);

    Gif的合成

01- (void)exportAnimatedGif:(CGImageSourceRef )gif :(NSMutableArray *)images

02 

03{

04 

05       NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"animated.gif"];

06 

07    CGImageDestinationRef destination = CGImageDestinationCreateWithURL(( CFURLRef)[NSURL fileURLWithPath:path],

08 

09                                                                        kUTTypeGIF,

10 

11                                                                        images.count,

12 

13                                                                        NULL);

14 

15    UIImage *image;

16 

17    for (int i = 0; i<images.count; i++)

18 

19    {

20 

21        image = images[i];

22 

23        CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,i,NULL));

24 

25        CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);

26 

27        NSNumber *delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);

28 

29        NSDictionary *gifDelay = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:delay forKey:(NSString *)kCGImagePropertyGIFDelayTime]

30 

31                                                             forKey:(NSString *)kCGImagePropertyGIFDictionary];

32 

33         

34 

35        CGImageDestinationAddImage(destination,image.CGImage, (CFDictionaryRef)gifDelay);

36 

37        CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);

38 

39    }

40 

41     

42 

43//    CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);

44 

45    CGImageDestinationFinalize(destination);

46 

47    CFRelease(destination);

48 

49    NSLog(@"animated GIF file created at %@", path);

50 

51 

52}

24.将一个UIView对象的内容保存为UIImage

01+ (UIImage*)imageFromView:(UIView*)view{

02 

03UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, view.layer.contentsScale);

04 

05[view.layer renderInContext:UIGraphicsGetCurrentContext()];

06 

07UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

08 

09UIGraphicsEndImageContext();

10 

11return image;

12 

13}

注意：生成的图片的scale和view的scale一致，这样才可以保证图片的效果和view显示的完全一致，使用renderInContext方法可以让subviews的内容也显示的图片里。