Java tutorial
/* 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.manueldeveloper; import org.apache.cordova.CallbackContext; import org.apache.cordova.CordovaPlugin; import org.apache.cordova.PluginResult; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.util.Log; import android.view.KeyEvent; import android.view.View; import android.view.View.OnKeyListener; public class VolumeButtonsListener extends CordovaPlugin implements OnKeyListener { private static final String VolumeButtonsListener_LOG = "VolumeButtonsListener"; private CallbackContext volumeCallbackContext; /** * Constructor of the VolumeButtonsListener class * * @date 27/02/2014 * @version 0.0.1 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ public VolumeButtonsListener() { volumeCallbackContext = null; } /** * Method which executes the Javascript request * * @param action: String object with the action to execute * @param args: JSONArray object with the arguments of the request * @param callbackContext: CallbackContext object for call back into Javascript * * @return "boolean" which indicates if the action is valid (true) or not (false) * * @date 10/12/2016 * @version 0.0.3 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException { // Check the action if (action.equals("start")) { // Check if the plugin is listening the volume button events if (this.volumeCallbackContext != null) { callbackContext.error("Volume buttons listener already running"); return true; } // Get the reference to the callbacks and start the listening process this.volumeCallbackContext = callbackContext; this.webView.getView().setOnKeyListener(this); // Don't return any result now PluginResult pluginResult = new PluginResult(PluginResult.Status.NO_RESULT); pluginResult.setKeepCallback(true); this.volumeCallbackContext.sendPluginResult(pluginResult); return true; } else if (action.equals("stop")) { // Erase the callbacks reference and stop the listening process sendSignal(new JSONObject(), false); // release status callback in Javascript side this.volumeCallbackContext = null; this.webView.getView().setOnKeyListener(null); callbackContext.success(); return true; } return false; } /** * Overwritten method for Android application lifecycle. It stops the key events listening process * * @date 10/12/2016 * @version 0.0.3 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ public void onDestroy() { // Stop the listening process this.webView.getView().setOnKeyListener(null); } /** * Overwritten method for Android application lifecycle. It stops the key events listening process * * @date 10/12/2016 * @version 0.0.3 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ public void onReset() { // Stop the listening process this.webView.getView().setOnKeyListener(null); } /** * Overwritten method to receive the Android key events * * @param view: View object who emit the signal (CordovaWebView) * @param keyCode: int with the identifier of the pressed key * @param keyEvent: KeyEvent object with the information of the event * * @return "boolean" which indicates if the listener has consumed the event (true) or not (false) [Always false to allow that the event spreading] * * @date 10/12/2016 * @version 0.0.3 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ public boolean onKey(View view, int keyCode, KeyEvent keyEvent) { // Check if the event is equal to KEY_DOWN if (keyEvent.getAction() == KeyEvent.ACTION_DOWN) { // Check what button has been pressed if (keyCode == KeyEvent.KEYCODE_VOLUME_UP) { // Create a new JSONObject with the information and send it JSONObject info = new JSONObject(); try { info.put("signal", new String("volume-up")); sendSignal(info, true); return true; } catch (JSONException ex) { Log.e(VolumeButtonsListener_LOG, ex.getMessage()); } } else if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) { // Create a new JSONObject with the information and send it JSONObject info = new JSONObject(); try { info.put("signal", new String("volume-down")); sendSignal(info, true); return true; } catch (JSONException ex) { Log.e(VolumeButtonsListener_LOG, ex.getMessage()); } } } return false; } /** * Method which sends back a new PluginResult to Javascript * * @param info: JSONObject object with the information to send back * @param keepCallback: boolean which indicates if there will be more results * * @date 27/02/2014 * @version 0.0.1 * @author ManuelDeveloper(manueldeveloper@gmail.com) */ private void sendSignal(JSONObject info, boolean keepCallback) { if (this.volumeCallbackContext != null) { PluginResult result = new PluginResult(PluginResult.Status.OK, info); result.setKeepCallback(keepCallback); this.volumeCallbackContext.sendPluginResult(result); } } }