Android: Unable to add window. Permission denied for this window type

Question

I'm working on an app where I need to display a window with some info ON the Lock Screen (KeyGuard) without unlocking the phone. I figured I could probably do it with WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG

But every time my app crashes with the following error:

android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@40ec8528 -- permission denied for this window type

These posts (here, here and here) all give the same answer. To add the following permission in the Manifest file.

android.permission.SYSTEM_ALERT_WINDOW

Solution that I have implemented but I am still getting the same error. Any idea of what I'm doing wrong?

Here are the permissions in my manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.droidpilot.keyguardwindow" >

<uses-sdk
    android:minSdkVersion="16"
    android:targetSdkVersion="21" />

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.VIBRATE" />

And this is the code I use to add the Window to the lock screen

WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
    LayoutInflater mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    mView = mInflater.inflate(R.layout.lock_screen_notif, null);

    WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG,
            WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
                    | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
                    | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
            PixelFormat.TRANSLUCENT
    );

    wm.addView(mView, params);

Anybody got any idea?

P.S. I'm testing on an HTC Desire 620 DS running Android 4.4.2

Answer 1

if you use apiLevel >= 19, don't use

WindowManager.LayoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT 

which gets the following error:

android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@40ec8528 -- permission denied for this window type

Use this instead:

LayoutParams.TYPE_TOAST or TYPE_APPLICATION_PANEL