iOS开发中一些有用的小代码

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 =http://mobile.51cto.com/ 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ViewnextWebView = [[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]; 

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 = http://mobile.51cto.com/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];

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：

-（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];

}

1. iOS中@class和 #import，两种方式的讨论