Question: I've been getting reports of some Xiaomi devices (e.g. Mi 2, running API level 21) not showing overlays. My app targets API 23.

There are [several](http://forum.xda-developers.com/xiaomi-mi-3/help/link-bubble-playing-nice-t2857607) [posts](http://en.miui.com/thread-30931-1-1.html) out there regarding this. It seems that MIUI devices do not enable this permission at install time (unlike other pre-Marshmallow devices).

Unfortunately, `Settings.canDrawOverlays()` only works on Android 23+.

1. What is the correct way to check whether this permission has not yet been enabled pre-Marshmallow?
2. Is there an Intent to take the user to the relevant MUIU settings page? Maybe: `new Intent("android.settings.action.MANAGE_OVERLAY_PERMISSION", packageName)` but I have no means to test this.

Answer: 
Checking if you have the drawOverlays permission is safer using this:

```
@SuppressLint("NewApi")
public static boolean canDrawOverlayViews(Context con){
    if(Build.VERSION.SDK_INT< Build.VERSION_CODES.LOLLIPOP){return true;}
    try { 
        return Settings.canDrawOverlays(con); 
    }
    catch(NoSuchMethodError e){ 
        return canDrawOverlaysUsingReflection(con); 
    }
}

public static boolean canDrawOverlaysUsingReflection(Context context) {

    try {

        AppOpsManager manager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
        Class clazz = AppOpsManager.class;
        Method dispatchMethod = clazz.getMethod("checkOp", new Class[] { int.class, int.class, String.class });
        //AppOpsManager.OP_SYSTEM_ALERT_WINDOW = 24
        int mode = (Integer) dispatchMethod.invoke(manager, new Object[] { 24, Binder.getCallingUid(), context.getApplicationContext().getPackageName() });

        return AppOpsManager.MODE_ALLOWED == mode;

    } catch (Exception e) {  return false;  }

}

```

Custom ROMs can have altered the OS so that that Settings.canDrawOverlays() is not available. This happened to me with Xiaomi devices and the app crashed.

Requesting the permission:

```
@SuppressLint("InlinedApi")
public static void requestOverlayDrawPermission(Activity act, int requestCode){
    Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION, Uri.parse("package:" + act.getPackageName()));
    act.startActivityForResult(intent, requestCode);

}

```
Here is the step by step how to handle this:

At first give below permission in manifest file:

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

```

Or 

```
<uses-permission-sdk-23 android:name="android.permission.SYSTEM_ALERT_WINDOW" />

```

Then handle rest of the things using below code:

```
 public final static int REQUEST_CODE = 65635;

    public void checkDrawOverlayPermission() {
        /** check if we already  have permission to draw over other apps */
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (!Settings.canDrawOverlays(this)) {
                /** if not construct intent to request permission */
                Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                        Uri.parse("package:" + getPackageName()));
                /** request permission via start activity for result */
                startActivityForResult(intent, REQUEST_CODE);
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode,  Intent data) {
        /** check if received result code
         is equal our requested code for draw permission  */
        if (requestCode == REQUEST_CODE) {
            // ** if so check once again if we have permission */
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (Settings.canDrawOverlays(this)) {
                    // continue here - permission was granted
                    goYourActivity();
                }
            }
        }
    }

```

Just call `checkDrawOverlayPermission()` from your LauncherActivity or anywhere as your requirements.

When you execute the project you will see a window and asked for enabling the permission. After allowing permission you will be able to do anything about this.