2021-05-11
作者:互联网
安卓开发之音乐盒
1.首先注册BroadcastReceiver
在AndroidManifest中的application标签下添加receiver子标签
//生成的receiver配置文件
<receiver
android:name=".MyReceiver"
android:enabled="true"
android:exported="true">
<intent-filter>
//自定义Action
<action android:name="MLY" />
</intent-filter>
</receiver>
2.在AndroidManifest.xml里配置service
<service
android:name=".MusicService"
android:enabled="true"
android:exported="true"></service>
3.创建一个assests文件,将歌曲放进文件里
4.在布局文件中,放入两个Textview控件以显示歌曲信息和四个ImageButton控件以实现相应功能
activity_main.xml文件代码:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="180dp"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="32dp"
android:layout_weight="1"
android:gravity="center"
android:text="歌曲"
android:textSize="20dp"
android:textColor="#9C27B0"
android:ellipsize="marquee"
android:marqueeRepeatLimit="marquee_forever"/> />
<TextView
android:id="@+id/author"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="演唱者"
android:textSize="20dp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="90dp"
android:orientation="horizontal">
<ImageButton
android:id="@+id/front"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/front" />
<ImageButton
android:id="@+id/play"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/play" />
<ImageButton
android:id="@+id/stop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/stop" />
<ImageButton
android:id="@+id/next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/next" />
</LinearLayout>
</LinearLayout>
5.编写Java文件
MainActivity.java中的代码:
package com.example.musicbox;
import java.io.IOException;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.res.AssetFileDescriptor;
import android.content.res.AssetManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.IBinder;
public class MusicService extends Service {
MyReceiver serviceReceiver;
AssetManager am;
String[] musics = new String[] { "wish.mp3", "promise.mp3", "beautiful.mp3" };
MediaPlayer mPlayer;
// 当前的状态,0x11代表没有播放;0x12代表正在播放;0x13代表暂停
int status = 0x11;
// 记录当前正在播放的音乐
int current = 0;
@Override
public IBinder onBind(Intent intent) { return null; }
@Override
public void onCreate() {
super.onCreate();
am = getAssets();
// 创建BroadcastReceiver
serviceReceiver = new MyReceiver();
// 创建IntentFilter
IntentFilter filter = new IntentFilter();
filter.addAction(MainActivity.CTL_ACTION);
registerReceiver(serviceReceiver, filter);
// 创建MediaPlayer
mPlayer = new MediaPlayer();
// 为MediaPlayer播放完成事件绑定监听器
mPlayer.setOnCompletionListener(new OnCompletionListener() // ①
{
@Override
public void onCompletion(MediaPlayer mp)
{
current++;
if (current >= 3)
{
current = 0;
}
//发送广播通知Activity更改文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("current", current);
// 发送广播,将被Activity组件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
// 准备并播放音乐
prepareAndPlay(musics[current]);
}
});
}
public class MyReceiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, Intent intent) {
int control = intent.getIntExtra("control", -1);
switch (control)
{
// 播放或暂停
case 1:
// 原来处于没有播放状态
if (status == 0x11)
{
// 准备并播放音乐
prepareAndPlay(musics[current]);
status = 0x12;
}
// 原来处于播放状态
else if (status == 0x12)
{
// 暂停
mPlayer.pause();
// 改变为暂停状态
status = 0x13;
}
// 原来处于暂停状态
else if (status == 0x13)
{
// 播放
mPlayer.start();
// 改变状态
status = 0x12;
}
break;
// 停止声音
case 2:
// 如果原来正在播放或暂停
if (status == 0x12 || status == 0x13)
{
// 停止播放
mPlayer.stop();
status = 0x11;
}
}
// 广播通知Activity更改图标、文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("update", status);
sendIntent.putExtra("current", current);
// 发送广播,将被Activity组件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
}
}
private void prepareAndPlay(String music) {
try {
// 打开指定音乐文件
AssetFileDescriptor afd = am.openFd(music);
mPlayer.reset();
// 使用MediaPlayer加载指定的声音文件。
mPlayer.setDataSource(afd.getFileDescriptor(),
afd.getStartOffset(), afd.getLength());
// 准备声音
mPlayer.prepare();
// 播放
mPlayer.start();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
onCreate()函数
用于获取相应按钮以及添加监听器、注册receiver
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 获取程序界面界面中的四个按钮
front=(ImageButton)this.findViewById(R.id.front);
play = (ImageButton) this.findViewById(R.id.play);
stop = (ImageButton) this.findViewById(R.id.stop);
next=(ImageButton)this.findViewById(R.id.next);
title = (TextView) findViewById(R.id.title);
author = (TextView) findViewById(R.id.author);
// 为四个按钮的单击事件添加监听器
play.setOnClickListener(this);
stop.setOnClickListener(this);
front.setOnClickListener(this);
next.setOnClickListener(this);
activityReceiver = new ActivityReceiver();
// 创建IntentFilter
IntentFilter filter = new IntentFilter();
// 指定BroadcastReceiver监听的Action
filter.addAction(UPDATE_ACTION);
// 注册BroadcastReceiver
registerReceiver(activityReceiver, filter);
Intent intent = new Intent(this, MusicService.class);
// 启动后台Service
startService(intent);
}
ActivityReceiver子类,负责监听从Service传回来的广播,并用switch控制系统状态,且定义了在音乐播放的不同状态下显示的图片
public class ActivityReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
// 获取Intent中的update消息,update代表播放状态
int update = intent.getIntExtra("update", -1);
// 获取Intent中的current消息,current代表当前正在播放的歌曲
int current = intent.getIntExtra("current", -1);
if (current >= 0)
{
title.setText(titleStrs[current]);
author.setText(authorStrs[current]);
}
switch (update)
{
case 0x11:
play.setImageResource(R.drawable.play);
status = 0x11;
break;
// 控制系统进入播放状态
case 0x12:
// 播放状态下设置使用暂停图标
play.setImageResource(R.drawable.pause);
// 设置当前状态
status = 0x12;
break;
// 控制系统进入暂停状态
case 0x13:
// 暂停状态下设置使用播放图标
play.setImageResource(R.drawable.play);
// 设置当前状态
status = 0x13;
break;
}
}
}
onClick函数,用switch判断点击事件,向Service发送广播
public void onClick(View source)
{
// 创建Intent
Intent intent = new Intent("org.xr.action.CTL_ACTION");
switch (source.getId())
{
// 按下播放/暂停按钮
case R.id.play:
intent.putExtra("control", 1);
break;
// 按下停止按钮
case R.id.stop:
intent.putExtra("control", 2);
break;
case R.id.front:
intent.putExtra("control",3);
break;
//按下下一首
case R.id.next:
intent.putExtra("control",4);
break;
}
// 发送广播,将被Service组件中的BroadcastReceiver接收到
sendBroadcast(intent);
}
}
MusicService.java
在最外层函数定义需要用到的变量和子类,String[]内容注意要和mainActivity中的对应
MyReceiver serviceReceiver;
AssetManager am;
String[] musics=new String[]{"beautiful.mp3","legendsneverdie.mp3","promise.mp3","wish.mp3"};
MediaPlayer mPlayer;
//当前状态,0x11表示没有播放,0x12代表正在播放,0x13代表暂停
int status=0x11;
//记录当前正在播放的音乐
int current=0;
onCreate函数
添加监听器、注册receiver,并向Activity发送广播
public void onCreate() {
super.onCreate();
am=getAssets();
//创建BroadcastReceiver
serviceReceiver=new MyReceiver();
//创建IntentFilter(过滤器)
IntentFilter filter=new IntentFilter();
filter.addAction(MainActivity.CTL_ACTION);
registerReceiver(serviceReceiver,filter);
//创建MediaPlayer
mPlayer=new MediaPlayer();
//为MediaPlayer播放完成事件绑定监听器
mPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
current++;
if (current>=4)
{
current=0;
}
//发送广播通知Activity更改文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("current",current);
//发送广播,将被Activity组件中的BroadcastReceiver接收
sendBroadcast(sendIntent);
//准备播放音乐
prepareAndPlay(musics[current]);
}
});
}
MyReceiver子类,接收MainActivity发来的信息,并发送广播,定义了接收到来自MainActivity的广播后的处理过程
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent) {
int control =intent.getIntExtra("control",-1);
switch (control)
{
//播放或暂停
case 1:
//原来处于没有播放状态
if (status==0x11)
{
//准备并播放音乐
prepareAndPlay(musics[current]);
status=0x12;
}
//原来处于播放状态
else if (status==0x12)
{
//暂停
mPlayer.pause();
//改变为暂停状态
status=0x13;
}
//原来处于暂停状态
else if (status==0x13)
{
//播放
mPlayer.start();
//改变状态
status=0x12;
}
break;
//停止声音
case 2:
// 如果原来正在播放或暂停
if (status == 0x12 || status == 0x13)
{
// 停止播放
mPlayer.stop();
status = 0x11;
}
break;
//播放上一首
case 3:
//原来处于没有播放或暂停状态
if (status==0x11||status==0x13)
{
if(current==0) {
current=3;
prepareAndPlay(musics[current]);
}
//准备并播放音乐
else {
current=current-1;
prepareAndPlay(musics[current]);
}
status=0x12;
}
//原来处于播放状态
else if (status==0x12)
{
//上一首//准备并播放音乐
if(current==0) {
current=3;
prepareAndPlay(musics[current]);
}
else {
current=current-1;
prepareAndPlay(musics[current]);
}
}
break;
//播放下一首
case 4:
//原来处于没有播放或暂停状态
if (status==0x11||status==0x13)
{
if(current==3) {
current=0;
prepareAndPlay(musics[current]);
} //准备并播放音乐
else {
current=current+1;
prepareAndPlay(musics[current]);
}
status=0x12;
}
//原来处于播放状态
else if (status==0x12)
{
//下一首
if(current==3) {
current=0;
prepareAndPlay(musics[current]);
}
else {
current=current+1;
prepareAndPlay(musics[current]);
}
}
break;
}
//广播通知Activity更改图标、文本框
Intent sendIntent=new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("update",status);
sendIntent.putExtra("current",current);
//发送广播,将被Activity组件中的BroadcastReceiver接收
sendBroadcast(sendIntent);
}
}
prepareAndPlay函数,准备并播放音乐
private void prepareAndPlay(String music)
{
try
{
//打开指定音乐文件
AssetFileDescriptor afd=am.openFd(music);
mPlayer.reset();
//使用MediaPlayer加载指定的音乐文件
mPlayer.setDataSource(afd.getFileDescriptor(),afd.getStartOffset(),afd.getLength());
//准备声音
mPlayer.prepare();
//播放
mPlayer.start();
}catch (IOException e) {
e.printStackTrace();
}
到这里整个程序就基本完成了。
6.运行结果截图:
标签:11,status,05,current,Intent,2021,new,播放,mPlayer 来源: https://blog.csdn.net/qq_54590671/article/details/116673716