代码片段

1.当前View画成Image

- (UIImage *) imageWithUIView:(UIView*) view
{    
UIGraphicsBeginImageContext(view.bounds.size); 
CGContextRef ctx = UIGraphicsGetCurrentContext();
[view.layer renderInContext:ctx];
UIImage* tImage = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); 
return tImage;
}

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.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 : @"
--%@
" ,boundary] dataUsingEncoding : NSUTF8StringEncoding ]];
[body  appendData :[[ NSString   stringWithString : @"Content-Disposition:form-data; name="userfile"; filename="2.png"
" ]  dataUsingEncoding : NSUTF8StringEncoding ]]; // 上传上去的图片名字
[body  appendData :[[ NSString   stringWithString : @"Content-Type: application/octet-stream

" ]  dataUsingEncoding : NSUTF8StringEncoding ]];
[body  appendData :[ NSData   dataWithData :imageData]];
[body  appendData :[[ NSString   stringWithFormat : @"
--%@--
" ,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.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;

5.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];

6.状态栏的网络活动风火轮是否旋转

[UIApplication sharedApplication].networkActivityIndicatorVisible ， 默认值是 NO 。

7.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);

8.让图片适应框的大小

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];

9.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];

#define CONST_animation_time 0.5#define CONST_enlarge_proportion 15.0
 
 
 
CGPoint UpPointOfView(UIView *view)
{
 return (CGPoint){view.center.x, 200+2+55/2};
};
 
10.放大UIImageView

- (void) circleAnimate:(UIImageView*)view
{
 CGContextRef context = UIGraphicsGetCurrentContext();
 [UIView beginAnimations:nil context:context];
 [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
 [UIView setAnimationDuration:CONST_animation_time];
 [view setCenter:UpPointOfView(view)];
  
  
 CABasicAnimation *scalingAnimation = (CABasicAnimation *)[view.layer animationForKey:@"scaling"];
  
 if (!scalingAnimation)
 {
  scalingAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];
  scalingAnimation.repeatCount=1;
  scalingAnimation.duration=CONST_animation_time;
  scalingAnimation.autoreverses=NO;
  scalingAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
  scalingAnimation.fromValue=[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.0, 1.0, 1.0)];
  scalingAnimation.toValue=[NSValue valueWithCATransform3D:CATransform3DMakeScale(CONST_enlarge_proportion, CONST_enlarge_proportion, 1.0)];
 }
  
 [view.layer addAnimation:scalingAnimation forKey:@"scaling"];
 view.layer.transform = CATransform3DMakeScale(CONST_enlarge_proportion, CONST_enlarge_proportion, 1.0);
 [UIView commitAnimations];
}
 
 

11.GIF图片解析


+ (NSMutableArray *)praseGIFDataToImageArray:(NSData *)data;

 {
    NSMutableArray *frames = [[NSMutableArray alloc] init];
    CGImageSourceRef src = CGImageSourceCreateWithData((CFDataRef)data, NULL);
    CGFloat animationTime = 0.f;
    if (src) {
        size_t l = CGImageSourceGetCount(src);
        frames = [NSMutableArray arrayWithCapacity:l];
        for (size_t i = 0; i < l; i++) {
            CGImageRef img = CGImageSourceCreateImageAtIndex(src, i, NULL);
            NSDictionary *properties = (NSDictionary *)CGImageSourceCopyPropertiesAtIndex(src, i, NULL);
            NSDictionary *frameProperties = [properties objectForKey:(NSString *)kCGImagePropertyGIFDictionary];
            NSNumber *delayTime = [frameProperties objectForKey:(NSString *)kCGImagePropertyGIFUnclampedDelayTime];
            animationTime += [delayTime floatValue];
            if (img) {
                [frames addObject:[UIImage imageWithCGImage:img]];
                CGImageRelease(img);
            }
        }
        CFRelease(src);
    }
     return frames;
}