ask for display over other apps permission in settings

app/src/main/java/org/schabi/newpipe/settings/VideoAudioSettingsFragment.java

@@ -1,12 +1,64 @@
 package org.schabi.newpipe.settings;
 
+import android.content.SharedPreferences;
+import android.os.Build;
 import android.os.Bundle;
+import android.provider.Settings;
+import android.view.View;
+
+import androidx.annotation.Nullable;
+
+import com.google.android.material.snackbar.Snackbar;
 
 import org.schabi.newpipe.R;
+import org.schabi.newpipe.util.PermissionHelper;
 
 public class VideoAudioSettingsFragment extends BasePreferenceFragment {
+
+    private SharedPreferences.OnSharedPreferenceChangeListener listener;
+
+    @Override
+    public void onCreate(@Nullable Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        listener = (sharedPreferences, s) -> {
+
+            // on M and above, if user chooses to minimise to popup player on exit and the app doesn't have
+            // display over other apps permission, show a snackbar to let the user give permission
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
+                    s.equals(getString(R.string.minimize_on_exit_key))) {
+
+                String newSetting = sharedPreferences.getString(s, null);
+                if (newSetting != null
+                        && newSetting.equals(getString(R.string.minimize_on_exit_popup_key))
+                        && !Settings.canDrawOverlays(getContext())) {
+
+                    Snackbar.make(getListView(), R.string.permission_display_over_apps, Snackbar.LENGTH_INDEFINITE)
+                            .setAction(R.string.settings,
+                                    view -> PermissionHelper.checkSystemAlertWindowPermission(getContext()))
+                            .show();
+
+                }
+            }
+        };
+    }
+
+
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
         addPreferencesFromResource(R.xml.video_audio_settings);
     }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        getPreferenceManager().getSharedPreferences().registerOnSharedPreferenceChangeListener(listener);
+
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        getPreferenceManager().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(listener);
+    }
 }

app/src/main/res/values/strings.xml

@@ -227,6 +227,7 @@
     <string name="saved_tabs_invalid_json">Using default tabs, error while reading saved tabs</string>
     <string name="restore_defaults">Restore defaults</string>
     <string name="restore_defaults_confirmation">Do you want to restore the defaults?</string>
+    <string name="permission_display_over_apps">Give permission to display over other apps</string>
     <!-- error activity -->
     <string name="sorry_string">Sorry, that should not have happened.</string>
     <string name="guru_meditation" translatable="false">Guru Meditation.</string>