Android：使用API​​ 25创建文件夹（7.1.2）

Question

请帮帮我！ 我的设备刚刚更新到Android 7.1.2，然后我的应用无法首次创建文件夹。（该代码适用于所有以前的Android版本，包括7.1.1）。

我尝试了什么：

• 将android.permission.WRITE_EXTERNAL_STORAGE添加到清单文件中

  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
  

• 检查onCreate（）

  的运行时权限

  private static final int REQUEST_CODE_PERMISSION = 1;
  private void checkPermissions() {
      if (Build.VERSION.SDK_INT >= 23) {
          String[] mPermission = {
                              Manifest.permission.READ_EXTERNAL_STORAGE, 
                              Manifest.permission.WRITE_EXTERNAL_STORAGE};
          grantPermissions(mPermission);
      } else createFolder("/MyFolder/");
  }
  
  private void grantPermissions(String[] mPermission) {
      if (ActivityCompat.checkSelfPermission(this, mPermission[0])
          != PackageManager.PERMISSION_GRANTED ||
          ActivityCompat.checkSelfPermission(this, mPermission[1])
          != PackageManager.PERMISSION_GRANTED) {
  
          ActivityCompat.requestPermissions(this, mPermission,REQUEST_CODE_PERMISSION);
      } else createFolder("/MyFolder/");
  }
  
  @Override
  public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
      super.onRequestPermissionsResult(requestCode, permissions, grantResults);
      switch (requestCode) {
          case REQUEST_CODE_PERMISSION: {
              if (grantResults.length > 0) {
                  if (grantResults.length == 2 &&
                      grantResults[0] == PackageManager.PERMISSION_GRANTED &&
                      grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                      createFolder("/MyFolder/");
                  } else  {Toast.makeText(this, "The app was not allowed to granted some Permissions. So that it cannot function properly. Please consider granting it these permissions", Toast.LENGTH_LONG).show();}
              } else  {}
          }
      }
  }
  

• 创建文件夹功能

  public static void createFolder(String folder) {
      File root = Environment.getExternalStorageDirectory();
      String path = root.getAbsolutePath() + folder;
      File fileFolder = new File(path);
      if (!fileFolder.exists()) 
          Log.e("Utilities","create "+folder+" : "+fileFolder.mkdirs());
  }
  

  使用7.1.2，第一次运行应用程序时，fileFolder.mkdirs（）始终返回false。重启应用程序，它返回true！有帮助吗？非常感谢！