Android开发笔记之广播,service实现音乐的播放暂停停止快进等功能

利用广播实现音乐的播放暂停停止快进等功能

broadast

1. 此处是service里面实现的功能

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.IBinder;
import android.util.Log;

public class MyMediaService extends Service {

public static final int PLAY = 1;
public static final int PAUSE = 2;
public static final int STOP = 3;
public static final int FORWARD = 4;
public static final int BACKWARD = 5;
MediaPlayer mMediaPlayer;

@Override
public void onCreate() {
    RegesterBroadcast();
    Log.d("sxh", "服务");
    super.onCreate();
}

@Override
public IBinder onBind(Intent intent) {
    return null;
}

/*******************************************************
 * create a broadcast and we can get the value by intent
 * In the receiving method we can judge the value which
 * is transferd through intent Then we can do something
 * by the value 
 */
public class MyMediaPlayerBroadcast extends BroadcastReceiver {

    public void onReceive(Context context, Intent intent) {
        Log.d("sxh", "广播");
        int type = intent.getIntExtra("type", -1);
        switch (type) {
        case PLAY:  play(); break;
        case PAUSE: pause();break;
        case STOP:  stop(); break;
        case FORWARD: forWard(); break;
        case BACKWARD: backWard(); break;
        default:
            break;
        }
    }
}

/**************************************************************************
 * Play the music method This method is adopted in the asynchronous loading
 * resources, Asynchronous loading resources will not block the UI thread So
 * he immediately to carry out The next procedure, so we call the
 * MediaPlayer Start method in the event of an asynchronous loading resource
 * listening in to finish This way is ready for playing music which is take
 * the
 */
public void play() {
    if (mMediaPlayer == null) {
        try {
            mMediaPlayer = MediaPlayer.create(this, R.raw.rihanna);
            setMediaPrepareAsync();
        } catch (Exception e) {
            e.printStackTrace();
        }
    } else if (mMediaPlayer != null && !mMediaPlayer.isPlaying()) {
        mMediaPlayer.start();
    }
}

/**************************************************************
 * the metnod is to pause the music
 * we need to judge the music  whether music in a state of playing
 * before pasuing the music
 */
public void pause(){
    if(mMediaPlayer != null && mMediaPlayer.isPlaying()){
        mMediaPlayer.pause();
    }
}
/*******************************************
 * the method is to stop the music
 * Before we stop the music, it is necessary
 *  to determine whether music is empty
 */
public void stop(){
    if(mMediaPlayer != null){
        mMediaPlayer.stop();
        mMediaPlayer.release();
        mMediaPlayer = null;
    }
}
/********************************************
 * The fast method of music
 */
public void forWard(){
    Log.i("sxh", "forWard");
    if (mMediaPlayer != null && mMediaPlayer.isPlaying()) {
        int position = mMediaPlayer.getCurrentPosition();
        mMediaPlayer.seekTo(position + 10000);
    }
}
public void backWard(){
    if(mMediaPlayer != null && mMediaPlayer.isPlaying()){
        int position = mMediaPlayer.getCurrentPosition();
        if(position >10000){
            position -= 10000;
        }else{
            position =0;
        }
        mMediaPlayer.seekTo(position);
    }
} 
/**************************************************************************
 * Set the audio loaded to monitor events, only after completion of loading
 * Can go to call the beginning of the multimedia method
 */
public void setMediaPrepareAsync() {
    mMediaPlayer.setOnPreparedListener(new OnPreparedListener() {
        public void onPrepared(MediaPlayer mp) {
            mMediaPlayer.start();
        }
    });
}

/******************************************
 * Dynamic registration broadcasting method
 */
public void RegesterBroadcast() {
    IntentFilter filter = new IntentFilter();
    filter.addAction("flag");
    registerReceiver(new MyMediaPlayerBroadcast(), filter);
}

}

---

主activity里面实现的代码如下
package com.example.day3demo.activity;

import com.example.day3demo.R;
import com.example.day3demo.service.MyMediaService;

import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener {

MediaPlayer mMediaPlayer;
Button mPlay, mPause, mStop;
TextView mTextView_one,mTextView_two;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initView();
}

/********************************
 * 初始化控件
 */
public void initView() {
    findViewById(R.id.play).setOnClickListener(this);
    findViewById(R.id.pause).setOnClickListener(this);
    findViewById(R.id.stop).setOnClickListener(this);
    findViewById(R.id.forward).setOnClickListener(this);
    findViewById(R.id.backward).setOnClickListener(this);
    mTextView_one =(TextView) findViewById(R.id.currenttime);
    mTextView_two = (TextView) findViewById(R.id.alltime);
    startService(new Intent(this, MyMediaService.class));
}

@Override
public void onClick(View v) {
    int type = 0;
    switch (v.getId()) {
    case R.id.play:
        type = MyMediaService.PLAY;
        break;
    case R.id.pause:
        type = MyMediaService.PAUSE;
        break;
    case R.id.stop:
        type = MyMediaService.STOP;
        break;
    case R.id.forward:
        type = MyMediaService.FORWARD;
        break;
    case R.id.backward:
        type = MyMediaService.BACKWARD;
        break;
    }
    sendBroadcastData(type);
}

private void sendBroadcastData(int type) {
    Intent intent = new Intent();
    intent.putExtra("type", type);
    intent.setAction("flag");
    sendBroadcast(intent);
}

}

在主activity我们主要实现广播的发送命令,控件的初始化和绑定监听事件,广播信号源我们采取自定义的信号源,利用intent把我们的发送命令传递到音乐服务类中去,在音乐服务类中,在接收方法中,利用广播接收到带有操作命令的intent,通intent.getIntExtra(“type”, -1);得到我们要操作的命令值,去执行音乐的播放-暂停-停止-快进-后退等服务.

以上就是所有的代码,布局没有贴上,很丑陋的布局,大家自己去建一个布局,相信你们会实现想要的效果的.