新的开始

Android音乐播放器的实现-Service 与 MediaP

2017-03-17  本文已影响11659人  minminaya

Android学习整理 - 系列

Android学习整理 - 6 -Service

Android学习整理- 8 -MediaPlayer 放歌

为了实现后台放歌，可以转移到Service中，具体的逻辑和在Activity中是差不多的

功能需求：

实现过程

下载4首歌曲改名a1,a2,a3,a4放进sd卡目录下Sounds文件夹

新建服务MediaService

    private static final String TAG = "MediaService";
    private MyBinder mBinder = new MyBinder();
    //标记当前歌曲的序号
    private int i = 0;
    //歌曲路径
    private String[] musicPath = new String[]{
            Environment.getExternalStorageDirectory() + "/Sounds/a1.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a2.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a3.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a4.mp3"
    };
  //这里要是路径有问题，就加上getAbsolutePath()，像下面这样
  //Environment.getExternalStorageDirectory().getAbsolutePath() + "/Sounds/a1.mp3",

    //初始化MediaPlayer
    public MediaPlayer mMediaPlayer = new MediaPlayer();



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

    public class MyBinder extends Binder {
     
    }

在MyBinder类里面添加逻辑功能暂停，播放，下一首，上一首，等

 /**
         * 播放音乐
         */
        public void playMusic() {
            if (!mMediaPlayer.isPlaying()) {
                //如果还没开始播放，就开始
                mMediaPlayer.start();
            }
        }

        /**
         * 暂停播放
         */
        public void pauseMusic() {
            if (mMediaPlayer.isPlaying()) {
                //如果还没开始播放，就开始
                mMediaPlayer.pause();
            }
        }

         /**
         * 下一首
         */
        public void nextMusic() {
            if (mMediaPlayer != null && i < 4 && i >= 0) {
                //切换歌曲reset()很重要很重要很重要，没有会报IllegalStateException
                mMediaPlayer.reset();
                iniMediaPlayerFile(i + 1);
                //这里的if只要是为了不让歌曲的序号越界，因为只有4首歌
                if (i == 2) {

                } else {
                    i = i + 1;
                }
                playMusic();
            }
        }

        /**
         * 上一首
         */
        public void preciousMusic() {
            if (mMediaPlayer != null && i < 4 && i > 0) {
                mMediaPlayer.reset();
                iniMediaPlayerFile(i - 1);
                if (i == 1) {

                } else {

                    i = i - 1;
                }
                playMusic();
            }
        }
  

        /**
         * 关闭播放器
         */
        public void closeMedia() {
            if (mMediaPlayer != null) {
                mMediaPlayer.stop();
                mMediaPlayer.release();
            }
        }

注意

在下一首和上一首的功能里重新调用 setDataSource时，要先reset再重新加载资源，不然会爆java.lang.IllegalStateException错误，

下面这段有点多余，也是MyBinder里面的，因为可以在Activity中直接获取到MediaPlayer的对象而不用像下面这样拐弯，嗯，暂时先这样写了

 /**
         * 获取歌曲长度
         **/
        public int getProgress() {

            return mMediaPlayer.getDuration();
        }

        /**
         * 获取播放位置
         */
        public int getPlayPosition() {

            return mMediaPlayer.getCurrentPosition();
        }
        /**
         * 播放指定位置
         */
        public void seekToPositon(int msec) {
            mMediaPlayer.seekTo(msec);
        }

接着载服务中MediaService中

/**
     * 添加file文件到MediaPlayer对象并且准备播放音频
     */
    private void iniMediaPlayerFile(int dex) {
        //获取文件路径
        try {
            //此处的两个方法需要捕获IO异常
            //设置音频文件到MediaPlayer对象中
            mMediaPlayer.setDataSource(musicPath[dex]);
            //让MediaPlayer对象准备
            mMediaPlayer.prepare();
        } catch (IOException e) {
            Log.d(TAG, "设置资源，准备阶段出错");
            e.printStackTrace();
        }
    }

加入权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

注册服务

<service android:name=".service.MediaService"/>

布局文件如下

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    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.minminaya.mediaservice.MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/play"
            android:layout_width="0dp"
            android:layout_height="50dp"
            android:layout_weight="1"
            android:text="paly"/>

        <Button
            android:id="@+id/pause"
            android:layout_width="0dp"
            android:layout_height="50dp"
            android:layout_weight="1"
            android:text="pause"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">


        <Button
            android:id="@+id/precious"
            android:layout_width="0dp"
            android:layout_height="50dp"
            android:layout_weight="1"
            android:text="precious"/>

        <Button
            android:id="@+id/next"
            android:layout_width="0dp"
            android:layout_height="50dp"
            android:layout_weight="1"
            android:text="next"/>


    </LinearLayout>

    <SeekBar
        android:layout_marginTop="20dp"
        android:id="@+id/seekbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <TextView
        android:text="当前进度："
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</LinearLayout>
预览

Activity中，首先先实现播放的4大功能，声明

    private MediaService.MyBinder mMyBinder;
    private Button playButton;
    private Button pauseButton;
    private Button nextButton;
    private Button preciousButton;
    //“绑定”服务的intent
    Intent MediaServiceIntent;

服务与活动的纽带ServiceConnection

 private ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            mMyBinder = (MediaService.MyBinder) service;
             Log.d(TAG, "Service与Activity已连接");
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
  
        }
    };

绑定id，这里所有view都绑了，button事件

private void iniView() {
        playButton = (Button) findViewById(R.id.play);
        pauseButton = (Button) findViewById(R.id.pause);
        nextButton = (Button) findViewById(R.id.next);
        preciousButton = (Button) findViewById(R.id.precious);
        mSeekBar = (SeekBar) findViewById(R.id.seekbar);
        mTextView = (TextView) findViewById(R.id.text1);
        playButton.setOnClickListener(this);
        pauseButton.setOnClickListener(this);
        nextButton.setOnClickListener(this);
        preciousButton.setOnClickListener(this);
    }

button事件详细

 @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.play:
                mMyBinder.playMusic();
                break;
            case R.id.pause:
                mMyBinder.pauseMusic();
                break;
            case R.id.next:
                mMyBinder.nextMusic();
                break;
            case R.id.precious:
                mMyBinder.preciousMusic();
                break;
        }
    }

接下来是onCreate方法，针对Android6.0以上的运行时权限，动态申请权限

      iniView();
        MediaServiceIntent = new Intent(this, MediaService.class);


        //判断权限够不够，不够就给
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            }, 1);
        } else {
            //够了绑定播放音乐的服务
            bindService(MediaServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
        }

运行时权限的回调，在Activity中的

//获取到权限回调方法
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull  String[]permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    bindService(MediaServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
                } else {
                    Toast.makeText(this, "权限不够获取不到音乐，程序将退出", Toast.LENGTH_SHORT).show();
                    finish();
                }
                break;
            default:
                break;
        }
    }

onDestroy方法种添加

        mMyBinder.closeMedia();
        unbindService(mServiceConnection);

这个时候可以播放了，进度条当然没有动

效果图

接下来实现进度条的功能

在Activity中实例化handler

    private Handler mHandler = new Handler();

    private SeekBar mSeekBar;
    private TextView mTextView;
    //进度条下面的当前进度文字，将毫秒化为m:ss格式
    private SimpleDateFormat time = new SimpleDateFormat("m:ss");

在ServiceConnection中添加

 mSeekBar.setMax(mMyBinder.getProgress());

            mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
                @Override
                public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                    //这里很重要，如果不判断是否来自用户操作进度条，会不断执行下面语句块里面的逻辑，然后就会卡顿卡顿
                    if(fromUser){
                        mMyBinder.seekToPositon(seekBar.getProgress());
//                    mMediaService.mMediaPlayer.seekTo(seekBar.getProgress());
                    }
                }

                @Override
                public void onStartTrackingTouch(SeekBar seekBar) {

                }

                @Override
                public void onStopTrackingTouch(SeekBar seekBar) {

                }
            });

            mHandler.post(mRunnable);

注意

还有一个runnable

 /**
     * 更新ui的runnable
     */
    private Runnable mRunnable = new Runnable() {
        @Override
        public void run() {
            mSeekBar.setProgress(mMyBinder.getPlayPosition());
            mTextView.setText(time.format(mMyBinder.getPlayPosition()) + "s");
            mHandler.postDelayed(mRunnable, 1000);
        }
    };

onDestroy中 mMyBinder.closeMedia();前添加

//我们的handler发送是定时1000s发送的，如果不关闭，MediaPlayer release掉了还在获取getCurrentPosition就会爆IllegalStateException错误
        mHandler.removeCallbacks(mRunnable);

注意关闭handle的队列，不然，转入后台播放时程序崩溃

1.gif

贴全部代码环节

全部Activity代码如下

package com.minminaya.mediaservice;

import android.Manifest;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.format.Time;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

import com.minminaya.mediaservice.service.MediaService;

import java.text.SimpleDateFormat;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Handler mHandler = new Handler();

    private static final String TAG = "MainActivity";
    private MediaService.MyBinder mMyBinder;
//    private MediaService mMediaService;

    private Button playButton;
    private Button pauseButton;
    private Button nextButton;
    private Button preciousButton;
    private SeekBar mSeekBar;
    private TextView mTextView;
    //进度条下面的当前进度文字，将毫秒化为m:ss格式
    private SimpleDateFormat time = new SimpleDateFormat("m:ss");
    //“绑定”服务的intent
    Intent MediaServiceIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iniView();
        MediaServiceIntent = new Intent(this, MediaService.class);


        //判断权限够不够，不够就给
        if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(MainActivity.this, new String[]{
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            }, 1);
        } else {
            //够了就设置路径等，准备播放
            bindService(MediaServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
        }
    }

    //获取到权限回调方法
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull  String[]permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    bindService(MediaServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
                } else {
                    Toast.makeText(this, "权限不够获取不到音乐，程序将退出", Toast.LENGTH_SHORT).show();
                    finish();
                }
                break;
            default:
                break;
        }
    }


    private ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            mMyBinder = (MediaService.MyBinder) service;
//            mMediaService = ((MediaService.MyBinder) service).getInstance();
            mSeekBar.setMax(mMyBinder.getProgress());

            mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
                @Override
                public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                    //这里很重要，如果不判断是否来自用户操作进度条，会不断执行下面语句块里面的逻辑，然后就会卡顿卡顿
                    if(fromUser){
                        mMyBinder.seekToPositon(seekBar.getProgress());
//                    mMediaService.mMediaPlayer.seekTo(seekBar.getProgress());
                    }
                }

                @Override
                public void onStartTrackingTouch(SeekBar seekBar) {

                }

                @Override
                public void onStopTrackingTouch(SeekBar seekBar) {

                }
            });

            mHandler.post(mRunnable);

            Log.d(TAG, "Service与Activity已连接");
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };


    private void iniView() {
        playButton = (Button) findViewById(R.id.play);
        pauseButton = (Button) findViewById(R.id.pause);
        nextButton = (Button) findViewById(R.id.next);
        preciousButton = (Button) findViewById(R.id.precious);
        mSeekBar = (SeekBar) findViewById(R.id.seekbar);
        mTextView = (TextView) findViewById(R.id.text1);
        playButton.setOnClickListener(this);
        pauseButton.setOnClickListener(this);
        nextButton.setOnClickListener(this);
        preciousButton.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.play:
                mMyBinder.playMusic();
                break;
            case R.id.pause:
                mMyBinder.pauseMusic();
                break;
            case R.id.next:
                mMyBinder.nextMusic();
                break;
            case R.id.precious:
                mMyBinder.preciousMusic();
                break;
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        //我们的handler发送是定时1000s发送的，如果不关闭，MediaPlayer release掉了还在获取getCurrentPosition就会爆IllegalStateException错误
        mHandler.removeCallbacks(mRunnable);

        mMyBinder.closeMedia();
        unbindService(mServiceConnection);
    }

    /**
     * 更新ui的runnable
     */
    private Runnable mRunnable = new Runnable() {
        @Override
        public void run() {
            mSeekBar.setProgress(mMyBinder.getPlayPosition());
            mTextView.setText(time.format(mMyBinder.getPlayPosition()) + "s");
            mHandler.postDelayed(mRunnable, 1000);
        }
    };

}

服务的

package com.minminaya.mediaservice.service;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.Environment;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;

import java.io.IOException;

/**
 * Created by NIWA on 2017/3/17.
 */

public class MediaService extends Service {

    private static final String TAG = "MediaService";
    private MyBinder mBinder = new MyBinder();
    //标记当前歌曲的序号
    private int i = 0;
    //歌曲路径
    private String[] musicPath = new String[]{
            Environment.getExternalStorageDirectory() + "/Sounds/a1.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a2.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a3.mp3",
            Environment.getExternalStorageDirectory() + "/Sounds/a4.mp3"
    };
    //初始化MediaPlayer
    public MediaPlayer mMediaPlayer = new MediaPlayer();


    public MediaService() {
        iniMediaPlayerFile(i);
    }


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

    public class MyBinder extends Binder {

//        /**
//         *  获取MediaService.this（方便在ServiceConnection中）
//         *
//         * *//*
//        public MediaService getInstance() {
//            return MediaService.this;
//        }*/
        /**
         * 播放音乐
         */
        public void playMusic() {
            if (!mMediaPlayer.isPlaying()) {
                //如果还没开始播放，就开始
                mMediaPlayer.start();
            }
        }

        /**
         * 暂停播放
         */
        public void pauseMusic() {
            if (mMediaPlayer.isPlaying()) {
                //如果还没开始播放，就开始
                mMediaPlayer.pause();
            }
        }

        /**
         * reset
         */
        public void resetMusic() {
            if (!mMediaPlayer.isPlaying()) {
                //如果还没开始播放，就开始
                mMediaPlayer.reset();
                iniMediaPlayerFile(i);
            }
        }

        /**
         * 关闭播放器
         */
        public void closeMedia() {
            if (mMediaPlayer != null) {
                mMediaPlayer.stop();
                mMediaPlayer.release();
            }
        }

        /**
         * 下一首
         */
        public void nextMusic() {
            if (mMediaPlayer != null && i < 4 && i >= 0) {
                //切换歌曲reset()很重要很重要很重要，没有会报IllegalStateException
                mMediaPlayer.reset();
                iniMediaPlayerFile(i + 1);
                //这里的if只要是为了不让歌曲的序号越界，因为只有4首歌
                if (i == 2) {

                } else {
                    i = i + 1;
                }
                playMusic();
            }
        }

        /**
         * 上一首
         */
        public void preciousMusic() {
            if (mMediaPlayer != null && i < 4 && i > 0) {
                mMediaPlayer.reset();
                iniMediaPlayerFile(i - 1);
                if (i == 1) {

                } else {

                    i = i - 1;
                }
                playMusic();
            }
        }

        /**
         * 获取歌曲长度
         **/
        public int getProgress() {

            return mMediaPlayer.getDuration();
        }

        /**
         * 获取播放位置
         */
        public int getPlayPosition() {

            return mMediaPlayer.getCurrentPosition();
        }
        /**
         * 播放指定位置
         */
        public void seekToPositon(int msec) {
            mMediaPlayer.seekTo(msec);
        }




    }


    /**
     * 添加file文件到MediaPlayer对象并且准备播放音频
     */
    private void iniMediaPlayerFile(int dex) {
        //获取文件路径
        try {
            //此处的两个方法需要捕获IO异常
            //设置音频文件到MediaPlayer对象中
            mMediaPlayer.setDataSource(musicPath[dex]);
            //让MediaPlayer对象准备
            mMediaPlayer.prepare();
        } catch (IOException e) {
            Log.d(TAG, "设置资源，准备阶段出错");
            e.printStackTrace();
        }
    }
}

Github源代码：MediaService

高级播放器。。。人类用的

上面的播放是固有的几个文件（连音频文件名都订好了，真坑）

有个博主，做的毕业项目，是一系列文章，感觉不错，
Android开源音乐播放器之播放器基本功能

注意事项，

几个注意点在上面了

上一篇下一篇

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