iOS开发中一些有用的小代码

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iOS开发中一些有用的小代码

转载：http://www.th7.cn/Program/IOS/201303/128264.shtml

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;

}

//裁剪图片

+(UIImage *)cutTheImage:(UIImage *)image withCGSize:(CGSize )size

{

if (image)

{

float min = MIN(image.size.width,image.size.height);

CGRect rectMAX = CGRectMake((image.size.width-min)/2, (image.size.height-min)/2, min, min);

CGImageRef subImageRef = CGImageCreateWithImageInRect(image.CGImage, rectMAX);

UIGraphicsBeginImageContext(rectMAX.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextDrawImage(context, CGRectMake(0, 0, min, min), subImageRef);

UIImage *viewImage = [UIImage imageWithCGImage:subImageRef];

UIGraphicsEndImageContext();

CGImageRelease(subImageRef);

return viewImage;

}

return nil;

}

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];

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];

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。

- (IBAction)dismissKeyBoard:(id)sender;

- (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。

- (IBAction)dimissKeyboard:(id)sender;

- (IBAction)dimissKeyboard:(id)sender {

[text resignFirstResponder];

}

23、Gif图片的解析

NSString *filePath = [[NSBundle mainBundle]pathForResource:@"bai3" ofType:@"gif"];

NSData *data = [NSData dataWithContentsOfFile:filePath];

CGImageSourceRef gif = CGImageSourceCreateWithData((CFDataRef)data, nil);

//获取gif的各种属性

CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,0,NULL));

NSLog(@"_______%@",gifprops);

NSInteger count =CGImageSourceGetCount(gif);

NSLog(@"________%d",count);

CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);

CFDictionaryRef delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);

NSLog(@"_______%@",delay);

//[gifDic objectForKey:(NSString *)kCGImagePropertyGIFDelayTime];

// NSNumber * w = CFDictionaryGetValue(gifprops, @"PixelWidth");

// NSNumber * h =CFDictionaryGetValue(gifprops, @"PixelHeight");

// float totalDuration = delay.doubleValue * count;

// float pixelWidth = w.intValue;

// float pixelHeight = h.intValue;

//将gif解析成UIImage类型对象，并加进images数组中

NSMutableArray *images = [NSMutableArray arrayWithCapacity:count];

for(int index=0;index<count;index++)

{

CGImageRef ref = CGImageSourceCreateImageAtIndex(gif, index, nil);

UIImage *img = [UIImage imageWithCGImage:ref];

[images addObject:img];

CFRelease(ref);

}

CFRelease(gifprops);

CFRelease(gif);

Gif的合成

- (void)exportAnimatedGif:(CGImageSourceRef )gif :(NSMutableArray *)images

{

NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"animated.gif"];

CGImageDestinationRef destination = CGImageDestinationCreateWithURL(( CFURLRef)[NSURL fileURLWithPath:path],

kUTTypeGIF,

images.count,

NULL);

UIImage *image;

for (int i = 0; i<images.count; i++)

{

image = images[i];

CFDictionaryRef gifprops =(CGImageSourceCopyPropertiesAtIndex(gif,i,NULL));

CFDictionaryRef gifDic = CFDictionaryGetValue(gifprops, kCGImagePropertyGIFDictionary);

NSNumber *delay = CFDictionaryGetValue(gifDic, kCGImagePropertyGIFDelayTime);

NSDictionary *gifDelay = [NSDictionary dictionaryWithObject:[NSDictionary dictionaryWithObject:delay forKey:(NSString *)kCGImagePropertyGIFDelayTime]

forKey:(NSString *)kCGImagePropertyGIFDictionary];

CGImageDestinationAddImage(destination,image.CGImage, (CFDictionaryRef)gifDelay);

CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);

}

// CGImageDestinationSetProperties(destination, ( CFDictionaryRef)gifprops);

CGImageDestinationFinalize(destination);

CFRelease(destination);

NSLog(@"animated GIF file created at %@", path);

} 24.将一个UIView对象的内容保存为UIImage

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

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

[view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}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。