iOS图片选择的优化与封装

前言

照片的选取在App中是相当普遍的场景,如用户修改头像、上传照片。一般给用户两种选择

1拍照
2从相册选取

在iOS中选择图片这个任务是通过UIImagePickerController来实现的,通过设置sourceType来决定是从相册选取还是拍照,当前的视图控制器需要实现UIImagePickerControllerDelegate协议的方法。

imagePickerController:didFinishPickingMediaWithInfo:
//用户选择了图片
imagePickerControllerDidCancel:
//用户取消选择

由于iOS系统的隐私保护机制,无论那种方式都必须先由用户授权否则我们没有权限,结果如下图

iOS图片选择的优化与封装_第1张图片
没有权限

1,我们希望这个体验进行优化,2,这个场景很多,我们希望将其模块化,以便复用和拆封ViewController。我们这里只讨论选择一张图片的情况,多选照片的类库代码,现成类库比较多。

实现

综合来说我们的流程如下:1.弹出视图供用户选择一种方式;2.确定App是否有相应的权限,如果没有,提示用户没有权限并尝试引导用户去设置里面进行授权;3.选择照片返回。注意:UIActionSheet和UIAlertView在iOS9中已经废弃,提倡使用UIAlertController。考虑后期的复用、维护与完善,我们将其进行封装先定义一个ImagePickerModelDelegate协议,用来和视图控制器进行交互。

@protocol ImagePickerModelDelegate
-(void)imagePickerDidFinishWithImage:(UIImage)image;
-(void)imagePickerDidCancel;
//弹出警告框的视图
-(UIView
)viewControllerView;
@end

新建NSObject的子类ImagePickerModel,并实现UIImagePickerControllerDelegate和UIActionSheetDelegate协议。声明两个方法

+(id)sharedInstance;
-(void)startShowSelectTypeViewWithViewController:(id)viewController andIsEdit:(BOOL)edit;

.m文件方法的实现

+(id)sharedInstance
{
    if (!model)
   {     
       model = [[ImagePickerModel alloc]init];  
       if([[UIDevice currentDevice]systemVersion]floatValue] >= 8.0)
      {
          isiOS8 = YES;
      } 
   }
    return model;
}
-(void)startShowSelectTypeViewWithViewController:(id)viewController andIsEdit:(BOOL)edit
{
     isEdit = edit;
    _delegate = viewController;
    UIActionSheet *actSheet = [[UIActionSheet alloc]initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"相册",@"拍照", nil];
       [actSheet showInView:[_delegate viewControllerView]];
       [self takePicFromAlbum];
}
-(void)actionSheet:(UIActionSheet *)actionSheet
clickedButtonAtIndex:(NSInteger)buttonIndex
{
     switch (buttonIndex)
     {
          case 0:
          {
               [self takePicFromAlbum];
               break;
          }
          case 1:
          {
               [self takePicFromCamera];
               break;
          }
          default:
          break;
     }
}```

无论那种操作之前,都先判断下权限

//从相册选取

  • (void)takePicFromAlbum
    {
    ALAuthorizationStatus author = [ALAssetsLibrary authorizationStatus];
    if (author == 1 || author == 2)
    {
    if(isiOS8)
    {
    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"警告" message:@"没有相册访问权限,请在设置-隐私-相册中进行设置!" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"设置",nil];
    }
    else
    {
    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"警告" message:@"没有相册访问权限,请在设置-隐私-相册中进行设置!" delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil];
    }
    [alertView show];
    return;
    }
    UIImagePickerController pick = [[UIImagePickerController alloc] init];
    pick.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    pick.delegate = self;
    pick.allowsEditing = isEdit;
    [(UIViewController
    )_delegate presentViewController:pick animated:YES completion:nil];
    }
    //从相机
  • (void)takePicFromCamera
    {
    AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
    if (authStatus == AVAuthorizationStatusRestricted || authStatus ==AVAuthorizationStatusDenied)
    {
    if(isiOS8)
    {
    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"警告" message:@"没有相机访问权限,请在设置-隐私-相机中进行设置!" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"设置",nil];
    }
    else
    {
    UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"警告" message:@"没有相机访问权限,请在设置-隐私-相机中进行设置!" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"设置",nil];
    }
    [alertView show];
    return;
    //无权限
    }
    if ([UIImagePickerController
    isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
    {
    UIImagePickerController pick = [[UIImagePickerController alloc] init];
    pick.sourceType = UIImagePickerControllerSourceTypeCamera;
    pick.delegate = self;
    pick.allowsEditing = isEdit;
    [(UIViewController
    )_delegate presentViewController:pick animated:YES completion:nil];
    }
    else
    {
    NSLog(@"没有相机权限!");
    }
    }

-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
//iOS8后允许打开系统设置
if (buttonIndex == 1)
{
[[UIApplication sharedApplication]openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}
}


选择或者取消后的操作

pragma mark - UIImagePickerController

  • (void)imagePickerController:(UIImagePickerController *)picker
    didFinishPickingMediaWithInfo:(NSDictionary *)info
    {
    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
    if (!image)
    {
    image = [info objectForKey:UIImagePickerControllerOriginalImage];
    }
    [_delegate imagePickerDidFinishWithImage:image];
    picker.delegate = nil;
    [picker dismissViewControllerAnimated:YES completion:nil];
    }
    -(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
    {
    picker.delegate = nil;
    [picker dismissViewControllerAnimated:YES completion:nil];
    [_delegate imagePickerDidCancel];
    }

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