有用的小代码

常用代码整理：

12. 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];

}

13. 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;

}

14. 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);

15. 给 imageView 加载图片

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

   [ imageView   setImage :myImage];

   [ self . view   addSubview : imageView ];

16. 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];

}

17. 跳到下个 View

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

[ self   presentModalViewController : nextWebView   animated : YES ];

// 创建一个 UIBarButtonItem 右边按钮

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

[ self . navigationItem   setRightBarButtonItem :rightButton];

设置 navigationBar 隐藏

self . navigationController . navigationBarHidden  =  YES ;//

iOS开发之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;

30. 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];

31. 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 ;

32. 好看的文字处理

以 tableView 中 cell 的 textLabel 为例子：

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;

33.  ———————-隐藏Status Bar—————————–
读者可能知道一个简易的方法 , 那就是在程序的 viewDidLoad 中加入

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

33. 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];

34.  键盘透明
textField.keyboardAppearance = UIKeyboardAppearanceAlert;

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

35 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);
36 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; 

37 显示 图像:
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];

38. 能让图片适应框的大小（没有确认）

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];

39. 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]; 

转载:http://www.cocoachina.com/bbs/read.php?tid=108916&fpage=2