Open failed: enoent (no such file or directory) / (operation not permitted)

One 、Android 11 Failed to upload and download resources ：open failed: ENOENT (No such file or directory)

Premise ： Find out Android 11 Uploading pictures and downloading files failed , Error log ：open failed: ENOENT (No such file or directory)

Turned out to be Android 11 Special permissions are required to access the file explorer ：MANAGE_EXTERNAL_STORAGE File management permissions
The previous application for permission was through Dialog Show to users , and Android 11 in the future adopt Activity Show the user (Intent Jump ).

1） The goal is sdk It is amended as follows 30：targetSdkVersion 30
2） List file registration ：

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

3） When the system is 11 And above apply for this permission

	 public void checkPermissions() {
    
	        // Apply for dangerous authority 
	        ....
	        // apply Android11 Special privileges 
	        requestManagerPermission();
	 }

    private void requestManagerPermission() {
    
    	// When the system is 11 And above 
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    
            //  Apply for permission without file management permission 
            if (!Environment.isExternalStorageManager()) {
    
                Intent intent = new Intent(Settings.ACTION_MANAGE_APP_ALL_FILES_ACCESS_PERMISSION);
                intent.setData(Uri.parse("package:" + mContext.getPackageName()));
                startActivityForResult(intent, REQUEST_MANAGER_PERMISSION);
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_MANAGER_PERMISSION && Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
    
        	// User denied permission , Reapply 
            if (!Environment.isExternalStorageManager()) {
    
                requestManagerPermission();
            }
        }
    }

Two 、 Failed to save screenshot ：open failed: EPERM (Operation not permitted)

Premise ： Find out Android 11 Failed to save screenshot , Error log ：open failed: ENOENT (Operation not permitted)

solve ： According to the version , Save the file in a different path .
Get external storage directory by default ,sdk>29 Get the outside SD Card cache directory .

String path = Environment.getExternalStorageDirectory().getPath();
if (Build.VERSION.SDK_INT > 29) {
    
	path = activity.getExternalFilesDir(null).getAbsolutePath() ;
}
File file = new File(path, fileName);
// Screenshot process ... Please ignore 
try {
    
      BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
      //  screenshots - take view Draw it as the original 
      View v = activity.getWindow().getDecorView();
      Bitmap bitmap = Bitmap.createBitmap(v.getWidth(), v.getHeight(),Bitmap.Config.RGB_565);
      Canvas c = new Canvas(bitmap);
      c.translate(-v.getScrollX(), -v.getScrollY());
      v.draw(c);
      //  Compress Bitmap, I won't support it png Image compression 
      bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
      bos.flush();
      bos.close();
      //  Insert the file into the system gallery 
      ContentValues values = new ContentValues();
      values.put(MediaStore.Images.Media.DATA, file.getAbsolutePath());
      values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");
      Uri uri =activity.getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
      //  Notify gallery to update 
      activity.sendBroadcast(newIntent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)));
      ToastUtils.showMessage(" Saved successfully ");
} catch (IOException e) {
    
	  e.printStackTrace();
	  ToastUtils.showMessage(e.getMessage());
}

Reference resources ：https://blog.csdn.net/dongxianfei/article/details/115449709
https://zhuanlan.zhihu.com/p/477539888