Making the 'Allow rotation' setting dependent on system state

The setting will not be available on a tablet, where rotation is
always enabled. On mobiles, it will be disabled when auto-rotate
is disabled in display settings.
Also removing content provider dependency from settings, as its in the
same process as launcher.

Bug: 28704055
Change-Id: Ibe6b1e67411fb0e4b2e36446710f463e4a3d6883

1 files changed, 56 insertions, 41 deletions

diff --git a/src/com/android/launcher3/SettingsActivity.java b/src/com/android/launcher3/SettingsActivity.java
index 4135d5be8..5ef6dd531 100644
--- a/src/com/android/launcher3/SettingsActivity.java
+++ b/src/com/android/launcher3/SettingsActivity.java
@@ -17,13 +17,14 @@
 package com.android.launcher3;
 
 import android.app.Activity;
-import android.os.AsyncTask;
+import android.content.ContentResolver;
+import android.database.ContentObserver;
 import android.os.Bundle;
+import android.os.Handler;
 import android.preference.Preference;
-import android.preference.Preference.OnPreferenceChangeListener;
 import android.preference.PreferenceFragment;
-import android.preference.PreferenceScreen;
-import android.preference.TwoStatePreference;
+import android.provider.Settings;
+import android.provider.Settings.System;
 
 /**
  * Settings activity for Launcher. Currently implements the following setting: Allow rotation
@@ -42,56 +43,70 @@ public class SettingsActivity extends Activity {
     /**
      * This fragment shows the launcher preferences.
      */
-    public static class LauncherSettingsFragment extends PreferenceFragment
-            implements OnPreferenceChangeListener {
+    public static class LauncherSettingsFragment extends PreferenceFragment {
+
+        private SystemDisplayRotationLockObserver mRotationLockObserver;
+
         @Override
         public void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
+            getPreferenceManager().setSharedPreferencesName(LauncherFiles.SHARED_PREFERENCES_KEY);
             addPreferencesFromResource(R.xml.launcher_preferences);
 
-            PreferenceScreen screen = getPreferenceScreen();
-            for (int i = screen.getPreferenceCount() - 1; i >= 0; i--) {
-                Preference pref = screen.getPreference(i);
-                if (pref instanceof TwoStatePreference) {
-                    setBooleanPrefUsingContentProvider((TwoStatePreference) pref);
-                }
+            // Setup allow rotation preference
+            Preference rotationPref = findPreference(Utilities.ALLOW_ROTATION_PREFERENCE_KEY);
+            if (getResources().getBoolean(R.bool.allow_rotation)) {
+                // Launcher supports rotation by default. No need to show this setting.
+                getPreferenceScreen().removePreference(rotationPref);
+            } else {
+                ContentResolver resolver = getContext().getContentResolver();
+                mRotationLockObserver = new SystemDisplayRotationLockObserver(rotationPref, resolver);
+
+                // Register a content observer to listen for system setting changes while
+                // this UI is active.
+                resolver.registerContentObserver(
+                        Settings.System.getUriFor(System.ACCELEROMETER_ROTATION),
+                        false, mRotationLockObserver);
+
+                // Initialize the UI once
+                mRotationLockObserver.onChange(true);
+                rotationPref.setDefaultValue(Utilities.getAllowRotationDefaultValue(getContext()));
             }
         }
 
         @Override
-        public boolean onPreferenceChange(Preference preference, Object newValue) {
-            Bundle extras = new Bundle();
-            extras.putBoolean(LauncherSettings.Settings.EXTRA_VALUE, (Boolean) newValue);
-            getActivity().getContentResolver().call(
-                    LauncherSettings.Settings.CONTENT_URI,
-                    LauncherSettings.Settings.METHOD_SET_BOOLEAN,
-                    preference.getKey(), extras);
-            return true;
+        public void onDestroy() {
+            if (mRotationLockObserver != null) {
+                getContext().getContentResolver().unregisterContentObserver(mRotationLockObserver);
+                mRotationLockObserver = null;
+            }
+            super.onDestroy();
         }
+    }
 
-        private void setBooleanPrefUsingContentProvider(final TwoStatePreference pref) {
-            pref.setPersistent(false);
-            pref.setEnabled(false);
+    /**
+     * Content observer which listens for system auto-rotate setting changes, and enables/disables
+     * the launcher rotation setting accordingly.
+     */
+    private static class SystemDisplayRotationLockObserver extends ContentObserver {
 
-            new AsyncTask<Void, Void, Boolean>() {
-                @Override
-                protected Boolean doInBackground(Void... params) {
-                    Bundle extras = new Bundle();
-                    extras.putBoolean(LauncherSettings.Settings.EXTRA_DEFAULT_VALUE, true);
-                    Bundle value = pref.getContext().getContentResolver().call(
-                            LauncherSettings.Settings.CONTENT_URI,
-                            LauncherSettings.Settings.METHOD_GET_BOOLEAN,
-                            pref.getKey(), extras);
-                    return value.getBoolean(LauncherSettings.Settings.EXTRA_VALUE);
-                }
+        private final Preference mRotationPref;
+        private final ContentResolver mResolver;
 
-                @Override
-                protected void onPostExecute(Boolean aBoolean) {
-                    pref.setChecked(aBoolean);
-                    pref.setEnabled(true);
-                    pref.setOnPreferenceChangeListener(LauncherSettingsFragment.this);
-                }
-            }.execute();
+        public SystemDisplayRotationLockObserver(
+                Preference rotationPref, ContentResolver resolver) {
+            super(new Handler());
+            mRotationPref = rotationPref;
+            mResolver = resolver;
+        }
+
+        @Override
+        public void onChange(boolean selfChange) {
+            boolean enabled = Settings.System.getInt(mResolver,
+                    Settings.System.ACCELEROMETER_ROTATION, 1) == 1;
+            mRotationPref.setEnabled(enabled);
+            mRotationPref.setSummary(enabled
+                    ? R.string.allow_rotation_desc : R.string.allow_rotation_blocked_desc);
         }
     }
 }