Android FileProvider删除文件

我在照片库应用程序工作，由于最近的牛轧糖更新，我无法从图库中删除文件。我发现我不得不使用Fileprovider文件访问，我想下面的代码，但它说Android FileProvider删除文件

04-25 12:52:03.031 3204-4133/com.zo.tns1 E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #3 
                 Process: com.zo.tns1, PID: 3204 
                 java.lang.RuntimeException: An error occurred while executing doInBackground() 
                  at android.os.AsyncTask$3.done(AsyncTask.java:325) 
                  at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354) 
                  at java.util.concurrent.FutureTask.setException(FutureTask.java:223) 
                  at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
                  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243) 
                  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
                  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
                  at java.lang.Thread.run(Thread.java:761) 
                 Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'java.io.File android.support.v4.content.FileProvider$PathStrategy.getFileForUri(android.net.Uri)' on a null object reference 
                  at android.support.v4.content.FileProvider.delete(FileProvider.java:520) 
                  at com.zo.tns1.tasks.DeleteMediaTask.doInBackground(DeleteMediaTask.java:117) 
                  at com.zo.tns1.tasks.DeleteMediaTask.doInBackground(DeleteMediaTask.java:39) 
                  at android.os.AsyncTask$2.call(AsyncTask.java:305) 
                  at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
                  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)  
                  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)  
                  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)  
                  at java.lang.Thread.run(Thread.java:761)

清单

<provider 
     android:name="android.support.v4.content.FileProvider" 
     android:authorities="com.zo.tns1.fileprovider" 
     android:exported="false" 
     android:grantUriPermissions="true"> 
     <meta-data 
      android:name="android.support.FILE_PROVIDER_PATHS" 
      android:resource="@xml/fileaccess_paths"/> 
    </provider>

fileaccess_paths.xml

<paths xmlns:android="http://schemas.android.com/apk/res/android"> 
<external-path name="all_files" path="." />

Java代码的

File f = new File(mediaList.get(i).getMediaPath());  
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.M) { 
       FileProvider provider = new FileProvider(); 
       Uri deleteFileUri = FileProvider.getUriForFile(context.getApplicationContext(), "com.zo.tns1.fileprovider", f); 
       context.grantUriPermission(context.getApplicationContext().getPackageName(), deleteFileUri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION); 
       provider.delete(deleteFileUri, null, null); 
       //context.getContentResolver().delete(deleteFileUri, null, null); 
      } else { 
       boolean b = f.delete(); 
       Log.d(TAG, "File delete -> " + b); 
      }

文件路径

/storage/emulated/0/DCIM/Camera/IMG_20170421_112804_1.jpg

来源

2017-04-21 Arun Shankar

哪条线路导致NPE？ –

我建议你阅读[FileProvider]的文档（https://developer.android.com/reference/android/support/v4/content/FileProvider.html）。 –

provider.delete（deleteFileUri，null，null）;这条线returing null事件虽然uri不为null –

你不能只用FileProvider构造一样，你需要通过你的上下文的内容解析器去。这会为您提供您在清单中指定的提供者。类似于

context.getContentResolver().delete(deleteFileUri, null, null);

来源

2017-04-22 19:58:16 GertG

这只会删除contentprovider中的数据，但该文件仍然存在 –

@ArunShankar FileProvider扩展ContentProvider，因此只要您获得正确的提供程序，就应该可以工作。 –

Android FileProvider删除文件

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