Android本地音乐播放器

一，需要知识点：

1，Drawerlayout侧滑菜单实现。

2，ListView的使用及其点击事件的监听。

3，如何打开文件管理器选择特定文件，并获取被选文件的路径。

4，Service服务的使用。

5，如何使用新线程动态给UI线程发送消息更新Seekbar进度。

6，MediaPlayer的使用。

二，写代码时遇到的坑。

1，在新开的线程中是不能修改UI组件的，否则程序会崩溃，写的时候因为这个程序一直崩溃我也很绝望。

2，找如何打开系统浏览器找了半天。

布局文件（线性布局）：

<?xml version="1.0" encoding="utf-8"?>

<android.support.v4.widget.DrawerLayout 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:id="@+id/drawerlayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/bg3"
    >
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    >
    <TextView
        android:id="@+id/imageview"
        android:layout_width="match_parent"
        android:layout_height="300dp"
         />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="当前正在播放：无歌曲"
        android:textSize="25sp"
        android:id="@+id/nowplayText"
        android:lines="2"
        />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:orientation="horizontal"
        android:layout_marginTop="10dp"
        >
        <TextView
            android:id="@+id/leftText"
            android:text="00:00"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center"
            android:layout_marginLeft="5dp"
            />
        <SeekBar
            android:id="@+id/seekbar"
            android:layout_width="272dp"
            android:layout_height="match_parent"

            />
        <TextView
            android:id="@+id/rightText"
            android:text="99:99"
            android:gravity="center"
            android:layout_width="wrap_content"
            android:layout_height="match_parent" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:orientation="horizontal"
        android:gravity="center"
        >
        <Button
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:id="@+id/open_btn"
            android:text="打开"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:id="@+id/stop_btn"
            android:text="停止"
            />
        <ImageButton
            android:id="@+id/imagebutton_exit"
            android:layout_width="50dp"
            android:layout_height="match_parent"
            android:background="@drawable/exit_btn"
            />


    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:orientation="horizontal"
        >
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/pre_btn"
            android:text="上一曲"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/start_btn"
            android:text="播放"
            />
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/next_btn"
            android:text="下一曲"
            />
        <Button
            android:id="@+id/menu_btn"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="菜单" />

    </LinearLayout>


</LinearLayout>
<LinearLayout
    android:layout_width="200dp"
    android:layout_height="match_parent"
    android:layout_gravity="end"
    android:id="@+id/leftview"
    >
    <ListView
        android:id="@+id/listview"
        android:layout_width="200dp"
        android:layout_height="match_parent"
        android:layout_gravity="end"
        android:choiceMode="singleChoice"
        android:divider="@android:color/transparent"
        android:dividerHeight="0dp"
        android:background="@drawable/bg4"

        >
    </ListView>


</LinearLayout>

</android.support.v4.widget.DrawerLayout>

MainActivity文件：

package com.example.my.musicplayer;

import android.Manifest;
import android.animation.ObjectAnimator;
import android.app.Activity;
import android.app.Notification;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.provider.MediaStore;
import android.support.annotation.RequiresApi;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.animation.Interpolator;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;
import java.sql.Time;
import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity implements View.OnClickListener,SeekBar.OnSeekBarChangeListener,AdapterView.OnItemClickListener {
    private Button start_btn,pre_btn,next_btn,open_btn,stop_btn,menu_btn;
    private TextView nowText,leftText,rightText,imageview;
    public SeekBar seekBar;
    private ListView listView=null;
    private ArrayAdapter<String>adapter;
    private MediaPlayer mediaPlayer;
    private MusicService musicService;
    private String path;
    public Handler handler;
    private ImageButton exit_btn;
    private int second;
    private int nowsecond;
    private CFilelist musicfile=new CFilelist();
    private int nowindex=0;
    private LinearLayout left_view=null;
    private DrawerLayout mDrawerLayout=null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        menu_btn= (Button) findViewById(R.id.menu_btn);
        menu_btn.setOnClickListener(this);
        start_btn= (Button) findViewById(R.id.start_btn);
        start_btn.setOnClickListener(this);
        pre_btn= (Button) findViewById(R.id.pre_btn);
        pre_btn.setOnClickListener(this);
        next_btn= (Button) findViewById(R.id.next_btn);
        next_btn.setOnClickListener(this);
        open_btn= (Button) findViewById(R.id.open_btn);
        open_btn.setOnClickListener(this);
        stop_btn= (Button) findViewById(R.id.stop_btn);
        stop_btn.setOnClickListener(this);
        seekBar= (SeekBar) findViewById(R.id.seekbar);
        seekBar.setOnSeekBarChangeListener(this);
        nowText= (TextView) findViewById(R.id.nowplayText);
        leftText= (TextView) findViewById(R.id.leftText);
        rightText= (TextView) findViewById(R.id.rightText);
        exit_btn= (ImageButton) findViewById(R.id.imagebutton_exit);
        exit_btn.setOnClickListener(this);
        listView= (ListView) findViewById(R.id.listview);
        adapter=new ArrayAdapter<String>(this,R.layout.support_simple_spinner_dropdown_item,musicfile.listname);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(this);
        imageview= (TextView) findViewById(R.id.imageview);
        listView.getBackground().setAlpha(150);
        left_view= (LinearLayout) findViewById(R.id.leftview);
        mDrawerLayout= (DrawerLayout) findViewById(R.id.drawerlayout);

        isGrantExternalRW(this);
        //通过绑定方式启动Service
        bindMusicService();
        handler=new Handler() {
            @Override
            public void handleMessage(Message msg) {
                if (msg.what == 0x123) {
                    if(mediaPlayer.isPlaying()) {
                        seekBar.setMax(second);
                        seekBar.setProgress(nowsecond);
                        leftText.setText(change(nowsecond));
                        rightText.setText(change(second));
                    }
                }
            }
        };
        new Timer().schedule(new TimerTask() {
            @Override
            public void run() {
                if(mediaPlayer!=null) {
                    second = musicService.mediaPlayer.getDuration();
                    nowsecond = musicService.mediaPlayer.getCurrentPosition();
                    //Toast.makeText(MainActivity.this,second+"",Toast.LENGTH_SHORT).show();
                    handler.sendEmptyMessage(0x123);
                }
            }
        },0,1000);
    }
    private void bindMusicService()
    {
        Intent intent=new Intent(this,MusicService.class);
        //启动服务
        startService(intent);
        //绑定服务
        bindService(intent,serviceConnection,this.BIND_AUTO_CREATE);
    }
private ServiceConnection serviceConnection=new ServiceConnection() {
    //回调函数；1，连接服务时调用2，取消服务连接
    //连接服务时调用
    @Override
    public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
       //获取service服务
        musicService=((MusicService.MyBinder)iBinder).getService();
        //获取mediaplayer
        mediaPlayer=musicService.mediaPlayer;

        path=musicService.path;
        //初始化进度条总时间
        int second=musicService.mediaPlayer.getDuration();
        second/=1000;
        rightText.setText("0"+second/60+":"+second%60);
    }
    //取消服务连接时调用
    @Override
    public void onServiceDisconnected(ComponentName componentName) {
        musicService=null;
    }
};

    //安卓6.0以上读取内存文件需要手动请求权限
    public static boolean isGrantExternalRW(Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && activity.checkSelfPermission(
                Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            activity.requestPermissions(new String[]{
                    //内存卡读写
                    Manifest.permission.READ_EXTERNAL_STORAGE,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            }, 1);
            return false;
        }
        return true;
    }
    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 1) {
            for (int i = 0; i < permissions.length; i++) {
                String permission = permissions[i];
                int grantResult = grantResults[i];
                if (permission.equals(Manifest.permission.READ_EXTERNAL_STORAGE)) {
                    if (grantResult == PackageManager.PERMISSION_GRANTED) {
                        //授权成功后的逻辑
                    } else {
                        requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
                    }
                }
            }
        }
    }



    @Override
    public void onClick(View view) {
        switch (view.getId())
        {
            case R.id.start_btn: {
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.pause();
                    //mediaPlayer.prepareAsync();
                    start_btn.setText("播放");
                    //objectAnimator.pause();
                } else {
                    mediaPlayer.start();
                    start_btn.setText("暂停");
                }
                break;
            }
            case R.id.stop_btn:
            {
                if(mediaPlayer!=null) {
                    musicService.tag = false;
                    mediaPlayer.stop();
                    mediaPlayer.prepareAsync();
                    start_btn.setText("播放");
                }
                    mediaPlayer.seekTo(0);
                    seekBar.setProgress(0);
                break;
            }
            case R.id.imagebutton_exit:
            {
                unbindService(serviceConnection);
                Intent intent=new Intent(this,MusicService.class);
                stopService(intent);
                try {
                    MainActivity.this.finish();
                }catch (Exception e)
                {
                    e.printStackTrace();
                }
                break;
            }
            case R.id.pre_btn:
            {
                if(musicfile.pathlist.size()==0)
                {
                    Toast.makeText(this, "文件为空不能播放，请点击打开添加歌曲再进行播放", Toast.LENGTH_SHORT).show();
                    break;
                }
                nowindex--;
                if(nowindex<0)
                {
                    if(musicfile.pathlist.size()!=0)
                   nowindex=musicfile.pathlist.size()-1;
                }
                if(mediaPlayer!=null) {
                    mediaPlayer.stop();
                    mediaPlayer.reset();
                    seekBar.setProgress(0);
                    start_btn.setText("播放");
                    //Toast.makeText(this, "当前播放路径为："+musicfile.pathlist.get(nowindex), Toast.LENGTH_SHORT).show();
                    try {
                        mediaPlayer.setDataSource(musicfile.pathlist.get(nowindex));
                        mediaPlayer.prepareAsync();
                        nowText.setText("当前正在播放："+musicfile.listname.get(nowindex));
                        //mediaPlayer.start();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                break;
            }
            case R.id.next_btn:
            {
                if(musicfile.pathlist.size()==0)
                {
                    Toast.makeText(this, "文件为空不能播放，请点击打开添加歌曲再进行播放", Toast.LENGTH_SHORT).show();
                    break;
                }
                nowindex++;
                if(nowindex>=musicfile.pathlist.size())
                {
                    if(musicfile.pathlist.size()!=0)
                        nowindex=0;
                }
                if(mediaPlayer!=null) {
                    mediaPlayer.stop();
                    mediaPlayer.reset();
                    seekBar.setProgress(0);
                    start_btn.setText("播放");
                    //Toast.makeText(this, "当前播放路径为："+musicfile.pathlist.get(nowindex), Toast.LENGTH_SHORT).show();
                    try {
                        mediaPlayer.setDataSource(musicfile.pathlist.get(nowindex));
                        mediaPlayer.prepareAsync();
                        nowText.setText("当前正在播放："+musicfile.listname.get(nowindex));
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                break;
            }
            case R.id.open_btn:
            {
                //打开系统自带文件浏览器
                Intent i=new Intent(Intent.ACTION_GET_CONTENT);
                i.setType("audio/*");
                i.addCategory(Intent.CATEGORY_OPENABLE);
                this.startActivityForResult(i,1);
                break;
            }
            case R.id.menu_btn:
            {
                if(!mDrawerLayout.isDrawerOpen(left_view))
                {
                    mDrawerLayout.openDrawer(left_view);
                }
                break;
            }

        }
    }
    //重写返回键的功能
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        //设置后台继续播放音乐
        if(keyCode==KeyEvent.KEYCODE_BACK)
        {
            moveTaskToBack(false);
        }
        return super.onKeyDown(keyCode, event);
    }

    private String change(int xx)
    {
        xx/=1000;
        String arg=new String();
        int t=xx/60;
        if(t<10){
            arg+="0";
        }
        arg+=t;
        t=xx%60;
        arg+=":";
        if(t<10){
            arg+="0";
        }
        arg+=t;
        return arg;
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
        leftText.setText(change(seekBar.getProgress()));
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        if(mediaPlayer!=null)
        {
            //如果音乐正在播放才更新播放进度
            if(mediaPlayer.isPlaying()) {
                mediaPlayer.seekTo(seekBar.getProgress());
            }
            else
            {
                seekBar.setProgress(0);
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(requestCode==1)
        {
            //将Url转换成真实路径
            Uri uri = data.getData();
            String[] proj = { MediaStore.Images.Media.DATA };
            Cursor actualimagecursor = getContentResolver().query(uri,proj,null,null,null);
            int actual_image_column_index = actualimagecursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            actualimagecursor.moveToFirst();
            String img_path = actualimagecursor.getString(actual_image_column_index);
            //Toast.makeText(this, img_path, Toast.LENGTH_LONG).show();
            musicfile.pathlist.add(img_path);
            //从文件末尾提取歌名
            String[] st=img_path.split("/");
            musicfile.listname.add(st[st.length-1]);
            Toast.makeText(this, "歌曲添加成功，点击下一首即可播放", Toast.LENGTH_SHORT).show();
            //更改ListView信息
            adapter.notifyDataSetChanged();
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        mediaPlayer.stop();
        mediaPlayer.reset();
        try {
            mediaPlayer.setDataSource(musicfile.pathlist.get(i));
            mediaPlayer.prepareAsync();
            nowText.setText("当前正在播放："+musicfile.listname.get(i));
            start_btn.setText("播放");
            mDrawerLayout.closeDrawer(left_view);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
class CFilelist
{
    public List<String>pathlist=new ArrayList<String>();
    public List<String>listname=new ArrayList<String>();
}

MusicService文件：

package com.example.my.musicplayer;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.Bundle;
import android.os.Environment;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
import android.widget.Toast;

import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

public class MusicService extends Service {
    public MediaPlayer mediaPlayer;
    public boolean tag=false;
    public MyBinder binder=new MyBinder();
    //内部储存卡路径
    public String path= Environment.getExternalStorageDirectory().getPath();
    public MusicService() {

        mediaPlayer=new MediaPlayer();
        try
        {
            mediaPlayer.setDataSource(path+"/music.mp3");
            mediaPlayer.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        return binder;
        //throw new UnsupportedOperationException("Not yet implemented");
    }

    public class MyBinder extends Binder
    {
        MusicService getService()
        {
            return MusicService.this;
        }
    }
}

播放器功能：

可以添加本地歌曲进行播放，添加的歌曲再右边侧滑栏显示，点击即可播放。

实现效果：