com.phonegap.BatteryListener.java Source code

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Here is the source code for com.phonegap.BatteryListener.java

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/*
   Licensed to the Apache Software Foundation (ASF) under one
   or more contributor license agreements.  See the NOTICE file
   distributed with this work for additional information
   regarding copyright ownership.  The ASF licenses this file
   to you 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.phonegap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.phonegap.api.Plugin;
import com.phonegap.api.PluginResult;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;

public class BatteryListener extends Plugin {

    private static final String LOG_TAG = "BatteryManager";

    BroadcastReceiver receiver;

    private String batteryCallbackId = null;

    /**
     * Constructor.
     */
    public BatteryListener() {
        this.receiver = null;
    }

    /**
     * Executes the request and returns PluginResult.
     * 
     * @param action        The action to execute.
     * @param args          JSONArry of arguments for the plugin.
     * @param callbackId    The callback id used when calling back into JavaScript.
     * @return              A PluginResult object with a status and message.
     */
    public PluginResult execute(String action, JSONArray args, String callbackId) {
        PluginResult.Status status = PluginResult.Status.INVALID_ACTION;
        String result = "Unsupported Operation: " + action;

        if (action.equals("start")) {
            if (this.batteryCallbackId != null) {
                return new PluginResult(PluginResult.Status.ERROR, "Battery listener already running.");
            }
            this.batteryCallbackId = callbackId;

            // We need to listen to power events to update battery status
            IntentFilter intentFilter = new IntentFilter();
            intentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
            if (this.receiver == null) {
                this.receiver = new BroadcastReceiver() {
                    @Override
                    public void onReceive(Context context, Intent intent) {
                        updateBatteryInfo(intent);
                    }
                };
                ctx.registerReceiver(this.receiver, intentFilter);
            }

            // Don't return any result now, since status results will be sent when events come in from broadcast receiver 
            PluginResult pluginResult = new PluginResult(PluginResult.Status.NO_RESULT);
            pluginResult.setKeepCallback(true);
            return pluginResult;
        }

        else if (action.equals("stop")) {
            removeBatteryListener();
            this.sendUpdate(new JSONObject(), false); // release status callback in JS side
            this.batteryCallbackId = null;
            return new PluginResult(PluginResult.Status.OK);
        }

        return new PluginResult(status, result);
    }

    /**
     * Stop battery receiver.
     */
    public void onDestroy() {
        removeBatteryListener();
    }

    /**
     * Stop the battery receiver and set it to null.
     */
    private void removeBatteryListener() {
        if (this.receiver != null) {
            try {
                this.ctx.unregisterReceiver(this.receiver);
                this.receiver = null;
            } catch (Exception e) {
                Log.e(LOG_TAG, "Error unregistering battery receiver: " + e.getMessage(), e);
            }
        }
    }

    /**
     * Creates a JSONObject with the current battery information
     * 
     * @param batteryIntent the current battery information
     * @return a JSONObject containing the battery status information
     */
    private JSONObject getBatteryInfo(Intent batteryIntent) {
        JSONObject obj = new JSONObject();
        try {
            obj.put("level", batteryIntent.getIntExtra(android.os.BatteryManager.EXTRA_LEVEL, 0));
            obj.put("isPlugged",
                    batteryIntent.getIntExtra(android.os.BatteryManager.EXTRA_PLUGGED, -1) > 0 ? true : false);
        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
        }
        return obj;
    }

    /**
     * Updates the JavaScript side whenever the battery changes
     * 
     * @param batteryIntent the current battery information
     * @return
     */
    private void updateBatteryInfo(Intent batteryIntent) {
        sendUpdate(this.getBatteryInfo(batteryIntent), true);
    }

    /**
     * Create a new plugin result and send it back to JavaScript
     * 
     * @param connection the network info to set as navigator.connection
     */
    private void sendUpdate(JSONObject info, boolean keepCallback) {
        if (this.batteryCallbackId != null) {
            PluginResult result = new PluginResult(PluginResult.Status.OK, info);
            result.setKeepCallback(keepCallback);
            this.success(result, this.batteryCallbackId);
        }
    }
}