Added UI widgets for new location settings page

Change-Id: I87eee999a4dd0189609f58d6f3e4ffe517d63a0e

src/com/android/settings/location/LocationEnabler.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.location;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.widget.CompoundButton;
+import android.widget.Switch;
+
+/**
+ * LocationEnabler is a helper to manage the Location on/off master switch
+ * preference. It turns on/off Location master switch and ensures the summary
+ * of the preference reflects the current state.
+ */
+public final class LocationEnabler implements CompoundButton.OnCheckedChangeListener {
+    private final Context mContext;
+    private Switch mSwitch;
+    private boolean mValidListener;
+
+    // TODO(lifu): listens to the system configuration change, and modify the switch state whenever
+    // necessary.
+    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+        }
+    };
+
+    public LocationEnabler(Context context, Switch switch_) {
+        mContext = context;
+        mSwitch = switch_;
+        mValidListener = false;
+    }
+
+    public void resume() {
+        mSwitch.setOnCheckedChangeListener(this);
+        mValidListener = true;
+    }
+
+    public void pause() {
+        mSwitch.setOnCheckedChangeListener(null);
+        mValidListener = false;
+    }
+
+    @Override
+    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
+        // TODO(lifu): modify the actual location settings when the user flip the master switch.
+    }
+
+    private void setChecked(boolean isChecked) {
+        if (isChecked != mSwitch.isChecked()) {
+            // set listener to null so that that code below doesn't trigger onCheckedChanged()
+            if (mValidListener) {
+                mSwitch.setOnCheckedChangeListener(null);
+            }
+            mSwitch.setChecked(isChecked);
+            if (mValidListener) {
+                mSwitch.setOnCheckedChangeListener(this);
+            }
+        }
+    }
+}