iOS通过UIAlertController弹出底部选择框来调用相机或者相册

  UIAlertController *alertVc = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
        UIAlertAction *cancle = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction *_Nonnull action) {
            
        }];
        
        UIAlertAction *camera = [UIAlertAction actionWithTitle:@"打开相机" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            
            UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
                imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
            }
            [self presentViewController:imagePicker animated:YEScompletion:nil];
            
        }];
        
        UIAlertAction *picture = [UIAlertAction actionWithTitle:@"打开相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            
            UIImagePickerController *pickerImage = [[UIImagePickerController alloc] init];
            if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {
                pickerImage.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
                pickerImage.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:pickerImage.sourceType];
                
            }
            pickerImage.delegate = self;
            pickerImage.allowsEditing = NO;
            
            [self presentViewController:pickerImage animated:YEScompletion:nil];
        }];
        [alertVc addAction:cancle];
        [alertVc addAction:camera];
        [alertVc addAction:picture];
        [self presentViewController:alertVc animated:YES completion:nil];


// 上面写到Button的点击事件方法里，下面直接复制就OK，记得遵守代理协议
UIImagePickerControllerDelegate, UINavigationControllerDelegate


// 选择图片
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    
    NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
    
    //当选择的类型是图片
    if ([type isEqualToString:@"public.image"])
    {
        //先把图片转成NSData
        UIImage* image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
        NSData *data;
        if (UIImagePNGRepresentation(image) ==nil)
        {
            data = UIImageJPEGRepresentation(image,1.0);
        }
        else
        {
            data = UIImagePNGRepresentation(image);
        }
        
        //图片保存的路径
        //这里将图片放在沙盒的documents文件夹中
        NSString *DocumentsPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
        
        //文件管理器
        NSFileManager *fileManager = [NSFileManager defaultManager];
        
        //把刚刚图片转换的data对象拷贝至沙盒中并保存为image.png
        [fileManager createDirectoryAtPath:DocumentsPath withIntermediateDirectories:YES attributes:nil error:nil];
        [fileManager createFileAtPath:[DocumentsPath stringByAppendingString:@"/userHeader.png"] contents:data attributes:nil];
        
        //关闭相册界面
        [picker dismissViewControllerAnimated:YEScompletion:nil];
        
        //加在视图中
        [self.mineView.headerButton setBackgroundImage:image forState:(UIControlStateNormal)];
        
    }
}
// 取消选取图片
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [picker dismissViewControllerAnimated:YEScompletion:nil];
}

        UIAlertAction *cancle = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction *_Nonnull action) {

        }];

        //修改按钮文字颜色

        [cancle setValue:[UIColor yellowColor] forKey:@"titleTextColor"];