PreferencesButton.java

// Copyright 2009 Google Inc.
//
// 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.google.android.stardroid.views;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.preference.PreferenceManager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.ImageButton;

import com.google.android.stardroid.R;
import com.google.android.stardroid.util.Analytics;
import com.google.android.stardroid.util.MiscUtil;

public class PreferencesButton extends ImageButton
    implements android.view.View.OnClickListener, OnSharedPreferenceChangeListener {
  private static final String TAG = MiscUtil.getTag(PreferencesButton.class);
  private static Analytics analytics;
  private OnClickListener secondaryOnClickListener;

  @Override
  public void setOnClickListener(OnClickListener l) {
    this.secondaryOnClickListener = l;
  }

  private Drawable imageOn;
  private Drawable imageOff;
  private boolean isOn;
  private String prefKey;
  private SharedPreferences preferences;
  private boolean defaultValue;

  public PreferencesButton(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    setAttrs(context, attrs);
    init();
  }

  public PreferencesButton(Context context, AttributeSet attrs) {
    super(context, attrs);
    setAttrs(context, attrs);
    init();
  }

  public PreferencesButton(Context context) {
    super(context);
    init();
  }

  /**
   * Sets the {@link Analytics} instance for reporting preference toggles.
   *
   * This class gets instantiated by the system and there's not obvious way to access anything
   * dagger-ey to inject the {@link Analytics}.  Since it's not vital to the class'
   * functioning and we'll probably kill this class anyway at some point I can live with this
   * hack.
   * @param analytics
   */
  public static void setAnalytics(Analytics analytics) {
    PreferencesButton.analytics = analytics;
  }

  public void setAttrs(Context context, AttributeSet attrs) {
    TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PreferencesButton);
    imageOn = a.getDrawable(R.styleable.PreferencesButton_image_on);
    imageOff = a.getDrawable(R.styleable.PreferencesButton_image_off);
    prefKey = a.getString(R.styleable.PreferencesButton_pref_key);
    defaultValue = a.getBoolean(R.styleable.PreferencesButton_default_value, true);
    Log.d(TAG, "Preference key is " + prefKey);
  }

  private void init() {
    super.setOnClickListener(this);
    preferences = PreferenceManager.getDefaultSharedPreferences(getContext());
    preferences.registerOnSharedPreferenceChangeListener(this);
    this.isOn = preferences.getBoolean(prefKey, defaultValue);
    Log.d(TAG, "Setting initial value of preference " + prefKey + " to " + isOn);
    setVisuallyOnOrOff();
  }

  private void setVisuallyOnOrOff() {
    setImageDrawable(isOn ? imageOn : imageOff);
  }
  
  private void setPreference() {
    Log.d(TAG, "Setting preference " + prefKey + " to... " + isOn);
    if (prefKey != null) {
      preferences.edit().putBoolean(prefKey, isOn).apply();
    }
  }

  @Override
  public void onClick(View v) {
    isOn = !isOn;
    if (analytics != null) {
      analytics.trackEvent(
          Analytics.USER_ACTION_CATEGORY, Analytics.PREFERENCE_BUTTON_TOGGLE, prefKey, isOn ? 1 : 0);
    }
    setVisuallyOnOrOff();
    setPreference();
    if (secondaryOnClickListener != null) {
      secondaryOnClickListener.onClick(v);
    }    
  }

  @Override
  public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
      String changedKey) {
    if (changedKey.equals(prefKey)) {
      isOn = sharedPreferences.getBoolean(changedKey, isOn);
      setVisuallyOnOrOff();
    }    
  }
}