這裏要完成音樂播放,我們需要使用到Broadcast實現模式,也就是我們所說的廣播
先展示一下項目成品哈:
首先是佈局文件:
(這裏的佈局我是直接採用的酷狗的音樂盒佈局)
layout/activity_main.xml
<?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"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="@+id/cover"
android:layout_width="match_parent"
android:layout_height="600dp"
android:layout_weight="1"
android:src="@drawable/composer" />
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="300dp"
android:layout_weight="1">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="20dp"
android:layout_weight="1"
android:ellipsize="marquee"
android:marqueeRepeatLimit="marquee_forever"
android:text="歌曲名"
android:gravity="center"
android:textColor="#000000"
android:textSize="30dp" />
<TextView
android:id="@+id/author"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:text="藝術家"
android:textSize="20dp" />
</LinearLayout>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="90dp"
android:gravity="center"
android:layout_marginBottom="10dp">
<ImageButton
android:id="@+id/pre"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/pre"
android:background="#FFFFFF"/>
<ImageButton
android:id="@+id/play"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/play"
android:background="#FFFFFF"/>
<ImageButton
android:id="@+id/next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/next"
android:background="#FFFFFF"/>
<!--停止在這不太好看,將其寬度設置爲0,先隱藏起來-->
<ImageButton
android:id="@+id/stop"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:src="@drawable/stop"
android:background="#FFFFFF"/>
</LinearLayout>
</LinearLayout>
在編寫main之前,我們不妨先將music類寫好
MusicService.java
package com.example.mymusicbox;
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;
import java.io.IOException;
public class MusicService extends Service
{
MyReceiver serviceReceiver;
AssetManager am;
String[] musics = new String[] { "composer.mp3" +
"", "bridge.mp3",
"graininear.mp3" };
MediaPlayer mPlayer;
// 當前的狀態,0x11代表沒有播放;0x12代表正在播放;0x13代表暫停
int status = 0x11;
// 記錄當前正在播放的音樂
int current = 0;
@Override
public IBinder onBind(Intent intent)
{
return null;
}
@Override
public void onCreate()
{
super.onCreate();
am = getAssets();
// 創建BroadcastReceiver
serviceReceiver = new MyReceiver();
// 創建IntentFilter
IntentFilter filter = new IntentFilter();
filter.addAction(MainActivity.CTL_ACTION);
registerReceiver(serviceReceiver, filter);
// 創建MediaPlayer
mPlayer = new MediaPlayer();
// 爲MediaPlayer播放完成事件綁定監聽器
mPlayer.setOnCompletionListener(new OnCompletionListener() // ①
{
@Override
public void onCompletion(MediaPlayer mp)
{
current++;
if (current >= 3)
{
current = 0;
}
//發送廣播通知Activity更改文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("current", current);
// 發送廣播,將被Activity組件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
// 準備並播放音樂
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)
{
// 播放或暫停
case 1:
// 原來處於沒有播放狀態
if (status == 0x11)
{
// 準備並播放音樂
prepareAndPlay(musics[current]);
status = 0x12;
}
// 原來處於播放狀態
else if (status == 0x12)
{
// 暫停
mPlayer.pause();
// 改變爲暫停狀態
status = 0x13;
}
// 原來處於暫停狀態
else if (status == 0x13)
{
// 播放
mPlayer.start();
// 改變狀態
status = 0x12;
}
break;
// 停止聲音
case 2:
// 如果原來正在播放或暫停
if (status == 0x12 || status == 0x13)
{
// 停止播放
mPlayer.stop();
status = 0x11;
}
case 3:
current--;
if(current < 0)
current = 0;
prepareAndPlay(musics[current]);
case 4:
current++;
if(current > musics.length-1)
current = 0;
prepareAndPlay(musics[current]);
}
// 廣播通知Activity更改圖標、文本框
Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
sendIntent.putExtra("update", status);
sendIntent.putExtra("current", current);
// 發送廣播,將被Activity組件中的BroadcastReceiver接收到
sendBroadcast(sendIntent);
}
}
private void prepareAndPlay(String music)
{
try
{
// 打開指定音樂文件
AssetFileDescriptor afd = am.openFd(music);
mPlayer.reset();
// 使用MediaPlayer加載指定的聲音文件。
mPlayer.setDataSource(afd.getFileDescriptor(),
afd.getStartOffset(), afd.getLength());
// 準備聲音
mPlayer.prepare();
// 播放
mPlayer.start();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
想必大家這是已經報錯了。。。不過不慌
隨後我們進入項目的xml中更改一個serviece
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mymusicbox">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".MusicService">
</service>
</application>
</manifest>
誒 增加了service之後 舒服啦
最後就是我們的main.java啦
MainActivity.java
package com.example.mymusicbox;
import android.support.v4.app.*;
import android.os.Bundle;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener
{
// 獲取界面中顯示歌曲標題、作者文本框
TextView title, author;
// 播放/暫停、停止按鈕
ImageButton play, stop;
// 上一首,下一首按鈕
ImageButton pre, next;
// 獲取封面
ImageView cover;
ActivityReceiver activityReceiver;
public static final String CTL_ACTION =
"org.crazyit.action.CTL_ACTION";
public static final String UPDATE_ACTION =
"org.crazyit.action.UPDATE_ACTION";
// 定義音樂的播放狀態,0x11代表沒有播放;0x12代表正在播放;0x13代表暫停
int status = 0x11;
String[] titleStrs = new String[] { "作曲家", "木橋小謠", "芒種" };
String[] authorStrs = new String[] { "李榮浩", "王梓鈺", "趙方婧" };
Integer[] covers = new Integer[] { R.drawable.composer, R.drawable.bridge, R.drawable.graininear};
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 獲取程序界面界面中的兩個按鈕
play = (ImageButton) this.findViewById(R.id.play);
stop = (ImageButton) this.findViewById(R.id.stop);
title = (TextView) findViewById(R.id.title);
author = (TextView) findViewById(R.id.author);
cover = findViewById(R.id.cover);
pre = this.findViewById(R.id.pre);
next = this.findViewById(R.id.next);
// 爲兩個按鈕的單擊事件添加監聽器
play.setOnClickListener(this);
stop.setOnClickListener(this);
// 爲上一首、下一首的單擊事件添加監聽器
pre.setOnClickListener(this);
next.setOnClickListener(this);
activityReceiver = new ActivityReceiver();
// 創建IntentFilter
IntentFilter filter = new IntentFilter();
// 指定BroadcastReceiver監聽的Action
filter.addAction(UPDATE_ACTION);
// 註冊BroadcastReceiver
registerReceiver(activityReceiver, filter);
Intent intent = new Intent(this, MusicService.class);
// 啓動後臺Service
startService(intent);
}
// 自定義的BroadcastReceiver,負責監聽從Service傳回來的廣播
public class ActivityReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
// 獲取Intent中的update消息,update代表播放狀態
int update = intent.getIntExtra("update", -1);
// 獲取Intent中的current消息,current代表當前正在播放的歌曲
int current = intent.getIntExtra("current", -1);
if (current >= 0)
{
title.setText(titleStrs[current]);
author.setText(authorStrs[current]);
cover.setImageResource(covers[current]);
}
switch (update)
{
case 0x11:
play.setImageResource(R.drawable.play);
status = 0x11;
break;
// 控制系統進入播放狀態
case 0x12:
// 播放狀態下設置使用暫停圖標
play.setImageResource(R.drawable.pause);
// 設置當前狀態
status = 0x12;
break;
// 控制系統進入暫停狀態
case 0x13:
// 暫停狀態下設置使用播放圖標
play.setImageResource(R.drawable.play);
// 設置當前狀態
status = 0x13;
break;
}
}
}
@Override
public void onClick(View source)
{
// 創建Intent
Intent intent = new Intent("org.crazyit.action.CTL_ACTION");
switch (source.getId())
{
// 按下播放/暫停按鈕
case R.id.play:
intent.putExtra("control", 1);
break;
// 按下停止按鈕
case R.id.stop:
intent.putExtra("control", 2);
break;
case R.id.pre:
intent.putExtra("control",3);
case R.id.next:
intent.putExtra("control",4);
}
// 發送廣播,將被Service組件中的BroadcastReceiver接收到
sendBroadcast(intent);
}
}
好了 至此,我們也就成功完成了一個簡單的音樂播放器。可以進行音樂的播放和上一首下一週的切換
最後是項目的源碼:
碼雲源碼