iOS开发中最有用关键的代码合集

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];

[align=left]8.设置navigationBar隐藏[/align][align=left] [/align]
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

//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

- (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

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

02

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

04

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

06

07 UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

08

09 UIGraphicsEndImageContext();

10

11 return 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。