iOS学习：调用相机，选择图片上传，带预览功能

一、新建工程

二、拖控件，创建映射

三、在.h中加入delegate

@interface ViewController : UIViewController<UIActionSheetDelegate,UIImagePickerControllerDelegate,UINavigationControllerDelegate>

四、实现按钮事件

-(IBAction)chooseImage:(id)sender {
    
    UIActionSheet *sheet;

// 判断是否支持相机

if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])

       {
           sheet  = [[UIActionSheet alloc] initWithTitle:@"选择" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"拍照",@"从相册选择", nil];

       }

    else {
        
        sheet = [[UIActionSheet alloc] initWithTitle:@"选择" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"从相册选择", nil];

    }
    
    sheet.tag = 255;
    
    [sheet showInView:self.view];
    
}

五、实现actionSheet delegate事件

判断是否支持相机，跳转到相机或相册界面

-(void) actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if (actionSheet.tag == 255) {
        
        NSUInteger sourceType = 0;
        
        // 判断是否支持相机
        if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
            
            switch (buttonIndex) {
                case 0:
                    // 取消
                    return;
                case 1:
                    // 相机
                    sourceType = UIImagePickerControllerSourceTypeCamera;
                    break;
                    
                case 2:
                    // 相册
                    sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
                    break;
            }
        }
        else {
            if (buttonIndex == 0) {
                
                return;
            } else {
                sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
            }
        }

// 跳转到相机或相册页面

UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
        
        imagePickerController.delegate = self;
        
        imagePickerController.allowsEditing = YES;
        
        imagePickerController.sourceType = sourceType;
        
        [self presentViewController:imagePickerController animated:YES completion:^{}];
        
        [imagePickerController release];
    }
}

六、实现ImagePicker delegate 事件

#pragma mark - image picker delegte
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [picker dismissViewControllerAnimated:YES completion:^{}];
    
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
    /* 此处info 有六个值 
     * UIImagePickerControllerMediaType; // an NSString UTTypeImage)
     * UIImagePickerControllerOriginalImage;  // a UIImage 原始图片
     * UIImagePickerControllerEditedImage;    // a UIImage 裁剪后图片
     * UIImagePickerControllerCropRect;       // an NSValue (CGRect)
     * UIImagePickerControllerMediaURL;       // an NSURL   
     * UIImagePickerControllerReferenceURL    // an NSURL that references an asset in the AssetsLibrary framework
     * UIImagePickerControllerMediaMetadata    // an NSDictionary containing metadata from a captured photo
     */
    // 保存图片至本地，方法见下文
    [self saveImage:image withName:@"currentImage.png"];
    
    NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"currentImage.png"];
    
    UIImage *savedImage = [[UIImage alloc] initWithContentsOfFile:fullPath];
    
    isFullScreen = NO;
    [self.imageView setImage:savedImage];
    
    self.imageView.tag = 100;
    
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
	[self dismissViewControllerAnimated:YES completion:^{}];
}

七、保存图片
高保真压缩图片方法

NSData * UIImageJPEGRepresentation ( UIImage *image, CGFloat compressionQuality
)

此方法可将图片压缩，但是图片质量基本不变，第二个参数即图片质量参数。

#pragma mark - 保存图片至沙盒
- (void) saveImage:(UIImage *)currentImage withName:(NSString *)imageName
{
    
    NSData *imageData = UIImageJPEGRepresentation(currentImage, 0.5);
    // 获取沙盒目录
    
    NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:imageName];
    // 将图片写入文件
    
    [imageData writeToFile:fullPath atomically:NO];
}

八、实现点击图片预览功能，滑动放大缩小，带动画

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    
    isFullScreen = !isFullScreen;
    UITouch *touch = [touches anyObject];
    
    CGPoint touchPoint = [touch locationInView:self.view];
    
    CGPoint imagePoint = self.imageView.frame.origin;
    //touchPoint.x ，touchPoint.y 就是触点的坐标
    
    // 触点在imageView内，点击imageView时 放大,再次点击时缩小
    if(imagePoint.x <= touchPoint.x && imagePoint.x +self.imageView.frame.size.width >=touchPoint.x && imagePoint.y <=  touchPoint.y && imagePoint.y+self.imageView.frame.size.height >= touchPoint.y)
    {
        // 设置图片放大动画
        [UIView beginAnimations:nil context:nil];
        // 动画时间
        [UIView setAnimationDuration:1];
        
        if (isFullScreen) {
            // 放大尺寸
            
            self.imageView.frame = CGRectMake(0, 0, 320, 480);
        }
        else {
            // 缩小尺寸
            self.imageView.frame = CGRectMake(50, 65, 90, 115);
        }
        
        // commit动画
        [UIView commitAnimations];
        
    }
    
}

九、上传图片，使用ASIhttpRequest类库实现，由于本文重点不是网络请求，故不对ASIHttpRequest详细讲述，只贴出部分代码

ASIFormDataRequest *requestReport  = [[ASIFormDataRequest alloc] initWithURL:服务器地址];
 
NSString *Path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"currentImage.png"];
              
[requestReport setFile:Path forKey:@"picturepath"];

[requestReport buildPostBody];

requestReport.delegate = self;

[requestReport startAsynchronous];

效果图如下：

          ->

      

      

ps：模拟器添加图片

1.模拟器无法调用相机；

2.模拟器添加图片方法：将图片拖至模拟器主屏，会由模拟器safari打开，长按可保存至模拟器相册，即可进行模拟器调试了。

3.关于调用相机，是系统自带的，不知道如何修改英文标题为中文，如cancel换为取消等，望知道的大虾们不吝告知，万分感谢

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