拒绝打开我创建的屏幕截图

Question

I'm using a rooted phone to take screen shots using shell and I want to open the image I took (it is visible in file explorer and it exists since I check it with File.exists() ). I asked for this permissions:

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="package.name.example">

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

    <application
        android:allowBackup="true"
...

In code I check if permissions are granted:

MainActivity.java

    //Check permissions
    if ((ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
            == PackageManager.PERMISSION_GRANTED) && (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)
            == PackageManager.PERMISSION_GRANTED)) {
        // permissions already given
    } else {
        // request permission
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}, 101);
    }

So on button click I take a screen shot using shell:

long startMiliseconds = System.currentTimeMillis();
Process captureScreen = Runtime.getRuntime().exec("su",null,null);
OutputStream os = captureScreen.getOutputStream();
os.write(("/system/bin/screencap -p "+"/sdcard/screencaps/ss"+ startMiliseconds +".png").getBytes("ASCII"));
os.flush();
os.close();

This will ask me for super user permission and take a screen shot of screen. When I try to access created image programaticly (I first check if file exists and it does):

String filePath = "/sdcard/screencaps/ss"+ startMiliseconds +".png";
Bitmap bMap = BitmapFactory.decodeFile(filePath);
img.setImageBitmap(bMap);

(img is an ImageView label) I get this error:

E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /sdcard/screencaps/ss1515070630835.png: open failed: EACCES (Permission denied)

EDIT: Seems it is permission related. I have changed min SDK and target SDK to 23. I changed handling of permission request to:

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    switch (requestCode) {
        case 101:

            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                //granted permission
                System.out.println("INFO: 1");
            } else {
                //not granted permission
                System.out.println("INFO: 2");
            }

            if (grantResults.length > 0 && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                //granted permission
                System.out.println("INFO: 3");
            } else {
                //not granted permission
                System.out.println("INFO: 4");
            }
            break;
        default:
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

And even if I press Allow in popup I get INFO: 2 and INFO: 4 which means that my permissions are not accepted. Sorry for not using loging.

EDIT 2: Seems like the problem is error I get after permission popup: Screen overlay detected

Answer 1

Hello your assuming sdcard is always /sdcard... Yes I know that sounds stupid. Try

Environment.getExternalStorageDirectory()+File.separator+"/screencaps/ss"

On small edit:

You haven't said if you have a popup appear on your screen? That might be you issue as well. User has to give app permission.

If so read this and look at the examples https://developer.android.com/training/permissions/requesting.html

**Edit : ** This is a huge shot in the dark but here is something you could put in your getting image method, where you parse the image to imageview

galleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI); 
startActivityForResult(galleryIntent, PICK_FROM_GALLERY);

Setting up a gallery intent. Or maybe adding

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