学步园

上传文件时，我们都的从本地中选择或用相机来拍摄得到文件。

一个上传按钮，单击事件

-(IBAction)btnClick{
    UIActionSheet* actionSheet = [[UIActionSheet alloc]
                                  initWithTitle:@"请选择文件来源"
                                  delegate:self
                                  cancelButtonTitle:@"取消"
                                  destructiveButtonTitle:nil
                                  otherButtonTitles:@"照相机",@"摄像机",@"本地相簿",@"本地视频",nil];
    [actionSheet showInView:self.view];
    [actionSheet release];
}

点击按钮触发的btnClick事件后将会弹出一个如下的选择筐：

接下来将要为UIActionSheet实现其中的委托了。

#pragma mark -
#pragma UIActionSheet Delegate
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSLog(@"buttonIndex = [%d]",buttonIndex);
    switch (buttonIndex) {
        case 0://照相机
        {   UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.allowsEditing = YES;
            imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
            [self presentModalViewController:imagePicker animated:YES];
            [imagePicker release];
        }
            break;
        case 1://摄像机
        {   UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.allowsEditing = YES;
            imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
            imagePicker.videoQuality = UIImagePickerControllerQualityTypeLow;
            [self presentModalViewController:imagePicker animated:YES];
            [imagePicker release];
        }
            break;
        case 2://本地相簿
        {   UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.allowsEditing = YES;
            imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            [self presentModalViewController:imagePicker animated:YES];
            [imagePicker release];
        }
            break;
        case 3://本地视频
        {   UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.allowsEditing = YES;
            imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            [self presentModalViewController:imagePicker animated:YES];
            [imagePicker release];
        }
            break;
        default:
            break;
    }
}

实现了UIActionSheet的委托后，要发现，我们使用了UIImagePickerController，这个类将帮我们实现选取文件，打开对应的选取方式。比如当ButtonIndex为0的时候，它将帮我们打开照相机，我们可以使用相机拍摄照片作为上传的选取文件。因此，在这里我们还要实现UIImagePickerController的委托：

#pragma mark -
#pragma UIImagePickerController Delegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(NSString*)kUTTypeImage]) {
        UIImage  *img = [info objectForKey:UIImagePickerControllerEditedImage];
        [self performSelector:@selector(saveImage:)  withObject:img afterDelay:0.5];
    } else if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(NSString*)kUTTypeMovie]) {
        NSString *videoPath = [[info objectForKey:UIImagePickerControllerMediaURL] path];
        self.fileData = [NSData dataWithContentsOfFile:videoPath];
    }
    [picker dismissModalViewControllerAnimated:YES];
}

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

然后保存并读取图片（上传服务器做头像时改变下图片的尺寸）

- (void)saveImage:(UIImage *)image {
//    NSLog(@"保存头像！");
//    [userPhotoButton setImage:image forState:UIControlStateNormal];
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *imageFilePath = [documentsDirectory stringByAppendingPathComponent:@"selfPhoto.jpg"];
    NSLog(@"imageFile->>%@",imageFilePath);
    success = [fileManager fileExistsAtPath:imageFilePath];
    if(success) {
        success = [fileManager removeItemAtPath:imageFilePath error:&error];
    }
    UIImage *smallImage=[self scaleFromImage:image toSize:CGSizeMake(80.0f, 80.0f)];//将图片尺寸改为80*80
    [UIImageJPEGRepresentation(smallImage, 1.0f) writeToFile:imageFilePath atomically:YES];//写入文件
     UIImage *selfPhoto = [UIImage imageWithContentsOfFile:imageFilePath];//读取图片文件
    [userPhotoButton setImage:selfPhoto forState:UIControlStateNormal];
}
// 改变图像的尺寸，方便上传服务器
- (UIImage *) scaleFromImage: (UIImage *) image toSize: (CGSize) size
{
    UIGraphicsBeginImageContext(size);
    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

之后，你选取的文件便保存在了filedata中。就可以随时过来调用了。