由于手机音量按键非常悲剧的掉了。无法控制手机音量大小。使用起来非常不方便。所以决定写一个小widget放在桌面能够随时控制音量吧。也算是解决一点便利问题。
1.一个简单的widget
由于我的需求非常easy不须要写一个程序再提供一个widget。所以直接一个AppWidgetProvider就好也就不须要AppWidgetHost 。
先在AndroidManifest里面增加一个receiver
<receiver android:name="WidgetProvider">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<intent-filter>
<action android:name="android.appwidget.action.ACTION_APPWIDGET_ENABLED" />
</intent-filter>
<intent-filter>
<action android:name="android.appwidget.action.ACTION_APPWIDGET_DELETED" />
</intent-filter>
<meta-data android:name="android.appwidget.provider"
android:resource="@xml/widget_provider"/>
</receiver>WidgetProvider是继承AppWidgetProvider的一个类，用来widget的详细响应实现。
里面的<meta-data android:name="android.appwidget.provider" android:resource="@xml/widget_provider"/>说明此receiver是widget，widget提供者的详细定义在xml文件widget_provider中。里面定义了widget的宽高，更新时间以及布局文件等。
widget_provider文件
<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="70dp"
android:minHeight="140dp"
android:updatePeriodMillis="86400000"
android:initialLayout="@layout/widget">
</appwidget-provider>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="@+id/button_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:textSize="14pt"
android:text="+" />
<Button
android:id="@+id/button_reduce"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button_add"
android:layout_below="@+id/button_add"
android:textSize="14pt"
android:text="-" />
</RelativeLayout>1 public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)
2 public void onDeleted(Context context, int[] appWidgetIds)
3 public void onEnabled(Context context)
4 public void onDisabled(Context context)
2 public void onDeleted(Context context, int[] appWidgetIds)
3 public void onEnabled(Context context)
4 public void onDisabled(Context context)
这几个函数用来响应AppWidget发出的对应的广播消息。他们的顺序是onEnabled ----> onUpdate ---> onDeleted
---> onDisabled。当你把widget放入桌面时，会运行onEnabled ----> onUpdate。然后到了定义的updatePeriodMillis时间时会运行一次Update，onUpdate方法会被调用，假设你从桌面删除widget则运行onDeleted
---> onDisabled方法。
在widget中对两个音量按钮设置监听器
public void onUpdate(Context context, int[] appIds) {
System.out.println("update");
RemoteViews rv = new RemoteViews(context.getApplicationContext().getPackageName(), R.layout.activity_main);
PendingIntent add = PendingIntent.getBroadcast(context, 0,
new Intent("CLICK_ACTION_ADD") , 0);
rv.setOnClickPendingIntent(R.id.button_add, add);
PendingIntent reduce = PendingIntent.getBroadcast(context, 0, new Intent("CLICK_ACTION_REDUCE"), 0);
rv.setOnClickPendingIntent(R.id.button_reduce, reduce);
AppWidgetManager appWidgetManger = AppWidgetManager
.getInstance(context);
appWidgetManger.updateAppWidget(appIds, rv);
}<span style="white-space:pre"> </span> <intent-filter>
<action android:name="CLICK_ACTION_ADD"/>
</intent-filter>
<intent-filter>
<action android:name="CLICK_ACTION_REDUCE"/>
</intent-filter>
AudioManager AM;
AM = (AudioManager)context.getSystemService("audio");
AM.adjustVolume(AudioManager.ADJUST_LOWER, AudioManager.FLAG_SHOW_UI|AudioManager.FLAG_PLAY_SOUND);后面的flag參数能够控制是否显示音量UI。以及更改时是否播放声音。
完整的WidgetProvider类
package com.frank.widgettest;
import android.app.PendingIntent;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.content.Intent;
import android.media.AudioManager;
import android.widget.RemoteViews;
public class WidgetProvider extends AppWidgetProvider{
AudioManager AM;
@Override
public void onEnabled(Context context) {
System.out.println("onEnabled");
super.onEnabled(context);
}
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
int[] appWidgetIds) {
System.out.println("update");
RemoteViews rv = new RemoteViews(context.getApplicationContext().getPackageName(), R.layout.widget);
PendingIntent add = PendingIntent.getBroadcast(context, 0,
new Intent("CLICK_ACTION_ADD") , 0);
rv.setOnClickPendingIntent(R.id.button_add, add);
PendingIntent reduce = PendingIntent.getBroadcast(context, 0, new Intent("CLICK_ACTION_REDUCE"), 0);
rv.setOnClickPendingIntent(R.id.button_reduce, reduce);
AppWidgetManager appWidgetManger = AppWidgetManager
.getInstance(context);
appWidgetManger.updateAppWidget(appWidgetIds, rv);
super.onUpdate(context, appWidgetManager, appWidgetIds);
}
@Override
public void onReceive(Context context, Intent intent) {
super.onReceive(context, intent);
if (intent.getAction().equals("CLICK_ACTION_ADD")) {
if(AM == null)
AM = (AudioManager)context.getSystemService("audio");
AM.adjustVolume(AudioManager.ADJUST_RAISE, AudioManager.FLAG_SHOW_UI|AudioManager.FLAG_PLAY_SOUND);
}
if(intent.getAction().equals("CLICK_ACTION_REDUCE")){
if(AM == null)
AM = (AudioManager)context.getSystemService("audio");
AM.adjustVolume(AudioManager.ADJUST_LOWER, AudioManager.FLAG_SHOW_UI|AudioManager.FLAG_PLAY_SOUND);
}
}
@Override
public void onDeleted(Context context, int[] appWidgetIds) {
System.out.println("deleted");
super.onDeleted(context, appWidgetIds);
}
}2.BroadcastReceiver能够取代AppWidgetProvider
其实第一次尝试的时候不知什么原因不能监听收到widget的onEnabled，onUpdate全部事件。一筹莫展时，看到Android API Guides里这样一段话
既然如此，我干脆直接使用一个BroadcastReceiver来取代AppWidgetProvider试试看吧。
结果没问题，各响应都能够收到音量控制正常。
public class WidgetProvider extends BroadcastReceiver{
AudioManager AM;
public void onEnabled() {
System.out.println("onEnabled");
}
public void onUpdate(Context context, int[] appIds) {
System.out.println("update");
RemoteViews rv = new RemoteViews(context.getApplicationContext().getPackageName(), R.layout.activity_main);
PendingIntent add = PendingIntent.getBroadcast(context, 0,
new Intent("CLICK_ACTION_ADD") , 0);
rv.setOnClickPendingIntent(R.id.button_add, add);
PendingIntent reduce = PendingIntent.getBroadcast(context, 0, new Intent("CLICK_ACTION_REDUCE"), 0);
rv.setOnClickPendingIntent(R.id.button_reduce, reduce);
AppWidgetManager appWidgetManger = AppWidgetManager
.getInstance(context);
appWidgetManger.updateAppWidget(appIds, rv);
}
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("CLICK_ACTION_ADD")) {
if(AM == null)
AM = (AudioManager)context.getSystemService("audio");
AM.adjustVolume(AudioManager.ADJUST_RAISE, AudioManager.FLAG_SHOW_UI|AudioManager.FLAG_PLAY_SOUND);
}
if(intent.getAction().equals("CLICK_ACTION_REDUCE")){
if(AM == null)
AM = (AudioManager)context.getSystemService("audio");
AM.adjustVolume(AudioManager.ADJUST_LOWER, AudioManager.FLAG_SHOW_UI|AudioManager.FLAG_PLAY_SOUND);
}
if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_ENABLED)){
onEnabled();
}
if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_UPDATE)){
int[] appWidgetIds = intent.getExtras().getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS);
onUpdate(context, appWidgetIds);
}
if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_DELETED)){
onDeleted();
}
}
public void onDeleted() {
System.out.println("deleted");
}后来我又新建一个项目使用AppWidgetProvider（第一个方案）也成功运行。
转载请注明出处http://blog.csdn.net/franksun1991/article/details/26454043