iOS 17个常用代码整理

.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];
}
.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(,,newSize.width,newSize.height)];
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    // End the context
    UIGraphicsEndImageContext();
    // Return the new image.
    return newImage;
}
.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);
    .给imageView加载图片
    UIImage *myImage = [UIImage imageNamed:@"1.jpg"];
    [imageView setImage:myImage];
    [self.view addSubview:imageView];
    .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(, , 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];
    }
    .跳到下个View
    nextWebView = [[WEBViewController alloc] initWithNibName:@"WEBViewController" bundle:nil];
    [self presentModalViewController:nextWebView animated:YES];

    //创建一个UIBarButtonItem右边按钮
    UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithTitle:@"右边" style:UIBarButtonItemStyleDone target:self action:@selector(clickRightButton)];
    [self.navigationItem setRightBarButtonItem:rightButton];
    设置navigationBar隐藏
    self.navigationController.navigationBarHidden = YES;//
    iOS开发之UIlabel多行文字自动换行 （自动折行）
    UIView *footerView = [[UIView alloc]initWithFrame:CGRectMake(, , , )];
    UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(, , , )];
    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 = ;
    .代码生成button
    CGRect frame = CGRectMake(, , 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 = ;
    [button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    .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;
    .好看的文字处理
    以tableView中cell的textLabel为例子：
    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;
    . ———————-隐藏Status Bar—————————–
    读者可能知道一个简易的方法,那就是在程序的viewDidLoad中加入
    [[UIApplication sharedApplication]setStatusBarHidden:YES animated:NO];
    . 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:];
    CGSize theSize = [theAlert frame].size;
    UIGraphicsBeginImageContext(theSize);
    [theImage drawInRect:CGRectMake(, , theSize.width-, theSize.height-)];//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];
    . 键盘透明
    textField.keyboardAppearance = UIKeyboardAppearanceAlert;

    状态栏的网络活动风火轮是否旋转
    [UIApplication sharedApplication].networkActivityIndicatorVisible，默认值是NO。

    35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(,));

    //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);
    36更改cell选中的背景
    UIView *myview = [[UIView alloc] init];
    myview.frame = CGRectMake(, , , );
    myview.backgroundColor = [UIColorcolorWithPatternImage:[UIImage imageNamed:@"0006.png"]];
    cell.selectedBackgroundView = myview;
    37显示图像:
    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];
    .能让图片适应框的大小（没有确认）
    NSString*imagePath = [[NSBundle mainBundle] pathForResource:@"XcodeCrash"ofType:@"png"];
    UIImage *image = [[UIImage alloc]initWithContentsOfFile:imagePath];
    UIImage *newImage= [image transformWidth:.f height:.f];
    UIImageView *imageView = [[UIImageView alloc]initWithImage:newImage];
    [newImagerelease];
    [image release];
    [self.view addSubview:imageView];
    .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(, , , )];
    [imgButton setBackgroundImage:(UIImage *)[self.imgArray objectAtIndex:indexPath.row] forState:UIControlStateNormal];
    imgButton.tag=[indexPath row];
    [imgButton addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];