iOS开发中一些实用小代码

本文介绍了一些实际开发过程中的简单的小功能代码，也可以说是iOS开发中一些实用小代码。



[align=left]1.判断邮箱格式是否正确的代码：[/align]
//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 = 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.对图库的操作
          选择相册

UIImagePickerControllerSourceType sourceType = 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];
}

[align=left]        detect为自己定义的方法，编辑选取照片后要实现的效果[/align]
         取消选择：

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

5 .跳到下个View

nextWebView = [[WEBViewController alloc] initWithNibName:@"WEBViewController" bundle:nil];
[self presentModalViewController:nextWebView animated:YES];

6. 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];

7.给imageView加载图片

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

[b]8.设置navigationBar隐藏[/b]

self.navigationController.navigationBarHidden = YES;//

[b][b]9.隐藏statusBar：在程序的viewDidLoad中加入[/b][/b]

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

10键盘透明：

textField.keyboardAppearance = UIKeyboardAppearanceAlert;

[b][b][b]11.状态栏的网络活动风火轮是否旋转：[/b][/b][/b]

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES ; //默认值是NO。

[b][/b]
[align=left]12.截取屏幕图片：
[/align]

//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);

[b][b]13[b].更改cell选中的背景：[/b][/b][/b]

UIView *myview = [[UIView alloc] init];
myview.frame = CGRectMake(0, 0, 320, 47);
myview.backgroundColor = [UIColorcolorWithPatternImage:[UIImage imageNamed:@"0006.png"]];
cell.selectedBackgroundView = myview;

97c5