iOS开发中一些实用小代码

-(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

- (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; 
} 

- (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); 
} 

UIImage *myImage = [UIImage imageNamed:@"1.jpg"]; 
[imageView setImage:myImage]; 
[self.view addSubview:imageView]; 

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]; 
} 

-(void)imagePickerControllerDIdCancel:(UIImagePickerController*)picker 
{ 
    [picker dismissModalViewControllerAnimated:YES]; 
} 

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];  

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]; 

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

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; 

[[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 = YES ; //默认值是NO。 

//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 = UIImagePNGRepresentation(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]; 

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]; 

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：

-（IBAction）textFieldDoneEditing：（id）sender{ 
      [sender resighFirstRespond]； 
} 

 通过点击背景回收键盘：（两个都得添加）

-（IBAction）textFieldDoneEditing：（id）sender{ 
　　[sender resighFirstRespond]； 
} 
-（IBAction）backgroundTapped：（id）sender{ 
　　[nameField resignFirstRespond]; 
　　[numberField resignFirstRespond]; 
} 

iOS开发中一些实用小代码到这也算是个完结了，大家可以收集与累积，通过实践来慢慢掌握这些。