在Android 7上写入外部存储

我想在我的Android应用程序中写入外部存储，但我似乎没有得到正确的权限。 该应用程序在Android 7上运行，因此我在运行时请求权限，如下所示：

public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); permission = ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don't have permission so prompt the user int ACCESS_EXTERNAL_STORAGE_STATE = 1; ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, ACCESS_EXTERNAL_STORAGE_STATE); } permission = ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don't have permission so prompt the user int ACCESS_EXTERNAL_STORAGE_STATE = 1; ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, ACCESS_EXTERNAL_STORAGE_STATE); } ... @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { super.onRequestPermissionsResult(requestCode, permissions, grantResults); switch (requestCode) { case 1: { if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { //reload my activity with permission granted or use the features what required the permission } else { Toast.makeText(this, "The app was not allowed to write to your storage. Hence, it cannot function properly. Please consider granting it this permission", Toast.LENGTH_LONG).show(); } } } } 

我做的一个观察是onRequestPermissionsResult似乎返回没有授予权限，但是在启动应用程序以允许写入外部存储时我也从未被提示过。

我在Manifest中设置了这些权限：

写入存储的代码在这里：

 public static void appendByteBuffer(byte[] data) { String filename = Environment.getExternalStorageDirectory().getAbsolutePath()+"/test.raw"; //filename value is "/storage/emulated/0/test.raw" File rawAudioFile = new File(filename); if (!rawAudioFile.exists()) { try { rawAudioFile.createNewFile(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } try (FileOutputStream output = new FileOutputStream(filename, true)) { output.write(data); } catch (IOException e) {} } 

03-16 14：50：49.988 19145-19306 /？ W / System.err：java.io.IOException：Permission denied 03-16 14：50：49.988 19145-19306 /？ W / System.err的：
at java.io.UnixFileSystem.createFileExclusively0（Native Method）03-16 14：50：49.988 19145-19306 /？ W / System.err：at java.io.UnixFileSystem.createFileExclusively（UnixFileSystem.java:280)03-16 14:50:49.989 19145-19306 /？ W / System.err：at java.io.File.createNewFile（File.java:948)03-16 14:50:49.989 19145-19306 /？ W / System.err：at com.meeter.study.AppUtils.appendByteBuffer（AppUtils.java:76）03-16 14：50：49.989 19145-19306 /？ W / System.err：at

Answer 1

对checkSelfPermission使用ContextCompat而不是ActivityCompat ：

更换：

 permission = ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE); permission = ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE); 

附：

 permission = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE); permission = ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE); 

然后，添加onRequestPermissionsResult方法来处理ALLOW，DENY选择。 希望这可以帮助。

 @Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { switch (requestCode) { case ACCESS_EXTERNAL_STORAGE_STATE: { // If request is cancelled, the result arrays are empty. if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { // Write to the storage (ex: call appendByteBuffer(byte[] data) here) } else { Toast.makeText(getApplicationContext(), "Please grant permission.", Toast.LENGTH_LONG).show(); } break; } }