018_04音效播放之MediaPlayer与SoundPool

　　音频资源文件一般放在Android应用下的/res/raw目录下。

　　如果应用程序经常需要播放密集，短促的音效，这时还用mediaPlayer就显得有些不合适。MediaPlayer存在如下缺点：

--资源占用量较高，延迟时间较长

--不支持多个音效同时播放

　　所以Android提供了SoundPool来播放音效，SoundPool使用音效池的概念来管理多个短促的音效。

下面源代码将使用MediaPlayer播放游戏背景音乐，使用SoundPool播放射击音效

package com.example.day18_05gameaudiodemo;

import android.app.Activity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.SoundPool;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {

    private SoundPool sp;
    private int sound1;
    private int sound2;
    private int sound3;
    private MediaPlayer mediaPlayer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        Button bt_gb = (Button) findViewById(R.id.bt_bg);
        Button bt_shoot1 = (Button) findViewById(R.id.bt_shoot1);
        Button bt_shoot2 = (Button) findViewById(R.id.bt_shoot2);
        Button bt_shoot3 = (Button) findViewById(R.id.bt_shoot3);

        
        bt_gb.setOnClickListener(this);
        bt_shoot1.setOnClickListener(this);
        bt_shoot2.setOnClickListener(this);
        bt_shoot3.setOnClickListener(this);

        
        sp = new SoundPool(3, AudioManager.STREAM_MUSIC, 0);
        sound1 = sp.load(this, R.raw.shoot1, 1);
        sound2 = sp.load(this, R.raw.shoot2, 1);
        sound3 = sp.load(this, R.raw.shoot3, 1);

        mediaPlayer = new MediaPlayer();
        mediaPlayer.reset();
        try {
            mediaPlayer.setDataSource(Environment.getExternalStorageDirectory()
                        .getAbsolutePath() + "/bgmusic.mp3");
            mediaPlayer.prepare();
        } catch ( Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
        case R.id.bt_bg:            
            if (mediaPlayer!=null) {
                mediaPlayer.start();
            }
            break;
        case R.id.bt_shoot1:
            sp.play(sound1, 1, 1, 0, 0, 1);
            break;
        case R.id.bt_shoot2:
            sp.play(sound2, 1, 1, 0, 0, 1);

                 break;
        case R.id.bt_shoot3:
            sp.play(sound3, 1, 1, 0, 0, 1);
                 break;
        default:
            break;
        }
    }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.day18_05gameaudiodemo.MainActivity" 
    android:background="@drawable/bg">

    <Button
        android:id="@+id/bt_bg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="背景音乐" />
    
    
    <LinearLayout 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"   
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:orientation="vertical"
        >
    <Button
        android:id="@+id/bt_shoot1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="shoot1" />
    
    <Button
        android:id="@+id/bt_shoot2"        
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="shoot2" />
    
    <Button       
         android:id="@+id/bt_shoot3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="shoot3" />
    </LinearLayout>

</RelativeLayout>