iOS儲存App中的照片到系統相簿或自建相簿的方法_IOS

儲存照片到系統相簿
儲存照片到系統相簿這個功能很多社交類的APP都有的，今天我們簡單講解一下，如何將圖片儲存到系統相簿（Photo Album）。

1.建立UIImageView

建立UIImageView是為了將照片展示出來，我們是要把UIImage儲存到系統相簿（Photo Album）:

複製代碼 代碼如下:

#define SCREEN [UIScreen mainScreen].bounds.size

self.image = [UIImage imageNamed:@"iOSDevTip"];
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake((SCREEN.width - 300) / 2, 70, 300, 150)];
imageView.image = self.image;
[self.view addSubview:imageView];

2.建立UIButton

建立UIButton並綁定actionClick:事件:

複製代碼 代碼如下:

UIButton *button = [[UIButton alloc] init];
button.frame = CGRectMake( 100, 300, SCREEN.width - 200, 40);
[button addTarget:self action:@selector(actionClick:) forControlEvents:UIControlEventTouchUpInside];
[button setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
[button setBackgroundColor:[UIColor orangeColor]];
[button setTitle:@"SavePhoto" forState:UIControlStateNormal];
[self.view addSubview:button];

- (void)actionClick:(UIButton *)button
{

}

3.儲存照片到系統相簿（Photo Album）

在actionClick:方法裡調用：

複製代碼 代碼如下:

UIImageWriteToSavedPhotosAlbum(self.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);

這個時候，我們想知道儲存是否成功，所以需要制定回調方法

複製代碼 代碼如下:

// 指定回調方法
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    if(!error){
        NSLog(@"save success");
    }else{
        NSLog(@"save failed");
    }
}

在這個方法裡，我們就知道照片是否儲存成功。

儲存照片到自己建立的相簿

接下來，我們來詳細講解一下關於系統相簿許可權擷取、儲存照片、建立自己的相簿等等功能。

1.建立自己的相簿

這也是一種比較建立的作法，建立自己的相簿，然後把照片或者視頻儲存到自己的相簿中。相關代碼如下：

複製代碼 代碼如下:

  ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library addAssetsGroupAlbumWithName:@"test" resultBlock:^(ALAssetsGroup *group) {

    //建立相簿成功

} failureBlock:^(NSError *error) {
    //失敗
}];

2.儲存照片

這個方法也是將照片儲存到系統相簿裡面，不是儲存到自己建立的相簿裡面。代碼如下：

複製代碼 代碼如下:

 ALAssetsLibrary *library = [[ALAssetsLibrary alloc]init];
[library writeImageToSavedPhotosAlbum:image.CGImage orientation:(ALAssetOrientation)image.imageOrientation completionBlock:^(NSURL *asSetUrl,NSError *error){
    if (error) {
       //失敗
    }else{
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"儲存成功"
                                                       message:nil
                                                      delegate:nil
                                             cancelButtonTitle:@"確定"
                                             otherButtonTitles:nil, nil];
        [alert show];

    }
}];

3.擷取許可權
在儲存照片之前，如果使用者關閉相簿許可權，這個時候是儲存失敗的。如果你不做任何處理，使用者是不會知道自己儲存失敗了。所以，我們可以在儲存照片之前，做出相應的提示。如何擷取這個許可權呢？一般有兩種方法：

（1）建立相簿失敗

（2）儲存照片失敗

在上面兩個方法建立自己的相簿和儲存照片的失敗結果裡，我們可以彈出擷取照片許可權失敗的提示。我們拿第一個建立相簿失敗來舉例：

複製代碼 代碼如下:

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library addAssetsGroupAlbumWithName:@"test" resultBlock:^(ALAssetsGroup *group)    {

      //建立相簿成功

} failureBlock:^(NSError *error) {
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"儲存失敗"
                                                       message:@"請開啟 設定-隱私-照片 來進行設定"
                                                      delegate:nil
                                             cancelButtonTitle:@"確定"
                                             otherButtonTitles:nil, nil];
    [alert show];
}];

在儲存照片失敗的結果裡，我們也可以彈出相應的提示，讓使用者開啟應用程式的相簿許可權。

4.儲存照片到自己的相簿

下面這段代碼是在大Google裡面找到的，親自測試過是可以用的，整理如下：

複製代碼 代碼如下:

#pragma mark - 建立相簿
- (void)createAlbum
{
    ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
    NSMutableArray *groups=[[NSMutableArray alloc]init];
    ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop)
    {
        if (group)
        {
            [groups addObject:group];
        }

        else
        {
            BOOL haveHDRGroup = NO;

            for (ALAssetsGroup *gp in groups)
            {
                NSString *name =[gp valueForProperty:ALAssetsGroupPropertyName];

                if ([name isEqualToString:@"iOSDevTip"])
                {
                    haveHDRGroup = YES;
                }
            }

            if (!haveHDRGroup)
            {
                //do add a group named "XXXX"
                [assetsLibrary addAssetsGroupAlbumWithName:@"iOSDevTip"
                                               resultBlock:^(ALAssetsGroup *group)
                 {
                     [groups addObject:group];

                 }
                                              failureBlock:nil];
                haveHDRGroup = YES;
            }
        }

    };
    //建立相簿
    [assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:listGroupBlock failureBlock:nil];

    [self saveToAlbumWithMetadata:nil imageData:UIImagePNGRepresentation(self.image) customAlbumName:@"iOSDevTip" completionBlock:^
     {
         //這裡可以建立添加成功的方法

     }
                     failureBlock:^(NSError *error)
     {
         //處理添加失敗的方法顯示alert讓它回到主線程執行，不然那個框框死活不肯彈出來
         dispatch_async(dispatch_get_main_queue(), ^{

             //添加失敗一般是由使用者不允許應用訪問相簿造成的，這邊可以取出這種情況加以判斷一下
             if([error.localizedDescription rangeOfString:@"User denied access"].location != NSNotFound ||[error.localizedDescription rangeOfString:@"使用者拒絕訪問"].location!=NSNotFound){
                 UIAlertView *alert=[[UIAlertView alloc]initWithTitle:error.localizedDescription message:error.localizedFailureReason delegate:nil cancelButtonTitle:NSLocalizedString(@"ok", nil) otherButtonTitles: nil];

                 [alert show];
             }
         });
     }];
}

- (void)saveToAlbumWithMetadata:(NSDictionary *)metadata
                      imageData:(NSData *)imageData
                customAlbumName:(NSString *)customAlbumName
                completionBlock:(void (^)(void))completionBlock
                   failureBlock:(void (^)(NSError *error))failureBlock
{

    ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
    __weak ALAssetsLibrary *weakSelf = assetsLibrary;
    void (^AddAsset)(ALAssetsLibrary *, NSURL *) = ^(ALAssetsLibrary *assetsLibrary, NSURL *assetURL) {
        [assetsLibrary assetForURL:assetURL resultBlock:^(ALAsset *asset) {
            [assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {

                if ([[group valueForProperty:ALAssetsGroupPropertyName] isEqualToString:customAlbumName]) {
                    [group addAsset:asset];
                    if (completionBlock) {
                        completionBlock();
                    }
                }
            } failureBlock:^(NSError *error) {
                if (failureBlock) {
                    failureBlock(error);
                }
            }];
        } failureBlock:^(NSError *error) {
            if (failureBlock) {
                failureBlock(error);
            }
        }];
    };
    [assetsLibrary writeImageDataToSavedPhotosAlbum:imageData metadata:metadata completionBlock:^(NSURL *assetURL, NSError *error) {
        if (customAlbumName) {
            [assetsLibrary addAssetsGroupAlbumWithName:customAlbumName resultBlock:^(ALAssetsGroup *group) {
                if (group) {
                    [weakSelf assetForURL:assetURL resultBlock:^(ALAsset *asset) {
                        [group addAsset:asset];
                        if (completionBlock) {
                            completionBlock();
                        }
                    } failureBlock:^(NSError *error) {
                        if (failureBlock) {
                            failureBlock(error);
                        }
                    }];
                } else {
                    AddAsset(weakSelf, assetURL);
                }
            } failureBlock:^(NSError *error) {
                AddAsset(weakSelf, assetURL);
            }];
        } else {
            if (completionBlock) {
                completionBlock();
            }
        }
    }];
}