Set FLAG_SECURE on every activity

app/src/main/java/me/impy/aegis/ui/AegisActivity.java

@@ -2,6 +2,7 @@ package me.impy.aegis.ui;
 
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
+import android.view.WindowManager;
 
 import me.impy.aegis.AegisApplication;
 
@@ -13,6 +14,10 @@ public abstract class AegisActivity extends AppCompatActivity {
         super.onCreate(savedInstanceState);
         _app = (AegisApplication) getApplication();
 
+        // set FLAG_SECURE on the window of every AegisActivity
+        getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
+
+        // set the theme
         boolean nightMode = _app.getPreferences().getBoolean("pref_dark_mode", false);
         setPreferredTheme(nightMode);
     }

app/src/main/java/me/impy/aegis/ui/IntroActivity.java

@@ -4,6 +4,7 @@ import android.Manifest;
 import android.content.Intent;
 import android.os.Bundle;
 import android.support.v4.app.Fragment;
+import android.view.WindowManager;
 
 import com.github.paolorotolo.appintro.AppIntro;
 import com.github.paolorotolo.appintro.AppIntroFragment;
@@ -53,6 +54,9 @@ public class IntroActivity extends AppIntro implements DerivationTask.Callback {
         super.onCreate(savedInstanceState);
         _app = (AegisApplication) getApplication();
 
+        // set FLAG_SECURE on the window of every IntroActivity
+        getWindow().setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE);
+
         showSkipButton(false);
         //showPagerIndicator(false);
         setGoBackLock(true);