Android利用SeekBar实现简单音乐播放器

一.demo简介 

利用aidl为activity绑定服务，利用handler机制，发送消息更新seekbar的ui，利用计时器定时更新seekbar的进度。实现对音乐的开始播放，到暂停，继续，以及停止播放的功能。以及实现拖动进度条播放音乐的功能。 

二.aidl接口 

利用aidl机制提供给mainactivity访问mymusicservice的方法，实现播放暂停等功能。

三.主要类代码

1.mymusicservice 

package my.com.mymusicp;

import android.app.service;
import android.content.intent;
import android.media.mediaplayer;
import android.os.bundle;
import android.os.ibinder;
import android.os.message;
import android.os.remoteexception;
import android.support.annotation.nullable;
import android.util.log;

import java.io.ioexception;
import java.util.timer;
import java.util.timertask;

/**
 * created by c_ljf on 16-12-26.
 */
public class mymusicservice extends service {
  private string tag="mymusicservice";
  private mediaplayer mediaplayer;

  @override
  public void oncreate() {
    super.oncreate();
    mediaplayer = new mediaplayer();
  }

  @nullable
  @override
  public ibinder onbind(intent intent) {
    return new mymusicbinder();
  }
  class mymusicbinder extends imymusicservice.stub{

    @override
    public void play() throws remoteexception {
      playmusic();
    }

    @override
    public void pause() throws remoteexception {
     pausemusic();
    }

    @override
    public void stop() throws remoteexception {
      stopmusic();
    }

    @override
    public void continueplay() throws remoteexception {
      replaymusic();
    }

    @override
    public void seekplayprogress(int position) throws remoteexception {
      seekplaypositiom(position);
    }

  }
  //播放音乐
  public void playmusic(){
    mediaplayer.reset();
    string url = "sdcard/music/fade.mp3";
    log.i(tag,url);
    try {
      mediaplayer.setdatasource(url);
      mediaplayer.prepare();
    } catch (ioexception e) {
      e.printstacktrace();
    }
     // might take long! (for buffering, etc)
    mediaplayer.start();
    //更新播放进度条
    seekplayprogress();
  }
  public void pausemusic(){
    mediaplayer.pause();
    log.i(tag,"暂停播放");

  }

  public void stopmusic(){
    mediaplayer.reset();
    log.i(tag,"停止播放");
    mediaplayer.stop();
  }

  @override
  public void ondestroy() {
    super.ondestroy();
  }
  public void seekplaypositiom(int positon){
    log.i(tag,"设置播放位置");
    mediaplayer.seekto(positon);
  }


  public void seekplayprogress(){
     /*1.获取当前歌曲的总时长*/
    final int duration=mediaplayer.getduration();

    //计时器对象
    final timer timer=new timer();
    final timertask task=new timertask() {
      @override
      public void run() {
        //开启线程定时获取当前播放进度
        int currentposition=mediaplayer.getcurrentposition();
        //利用message给主线程发消息更新seekbar进度
        message ms=message.obtain();
        bundle bundle=new bundle();
        bundle.putint("duration",duration);
        log.i(tag,"歌曲总长度"+duration);
        bundle.putint("currentposition",currentposition);
        log.i(tag,"当前长度"+currentposition);
        //设置发送的消息内容
        ms.setdata(bundle);
        //发送消息
        mainactivity.handler.sendmessage(ms);
      }
    };
     timer.schedule(task,300,500);
    //当播放结束时停止播放
    mediaplayer.setoncompletionlistener(new mediaplayer.oncompletionlistener() {
      @override
      public void oncompletion(mediaplayer mp) {
        log.i(tag,"取消计时任务");
        timer.cancel();
        task.cancel();
      }
    });

  }
  public void replaymusic() {
    log.i(tag, "继续播放音乐");
    mediaplayer.start();
  }
}

2.mainactivity 

package my.com.mymusicp;

import android.manifest;
import android.app.activity;
import android.content.componentname;
import android.content.intent;
import android.content.serviceconnection;
import android.content.pm.packagemanager;
import android.os.bundle;
import android.os.handler;
import android.os.ibinder;
import android.os.message;
import android.os.remoteexception;
import android.support.v4.app.activitycompat;
import android.support.v7.app.appcompatactivity;
import android.view.view;
import android.widget.button;
import android.widget.seekbar;

public class mainactivity extends appcompatactivity {
  private imymusicservice imymusicservice;
  private static seekbar seekbar;
  private button btpause_play;
  private boolean b=true;//判断暂停和继续播放
  public static handler handler=new handler(){
    @override
    public void handlemessage(message msg) {
      //处理消息
      bundle bundle=msg.getdata();
      //获取歌曲长度和当前播放位置，并设置到进度条上
      int duration=bundle.getint("duration");
      int currentposition=bundle.getint("currentposition");
      seekbar.setmax(duration);
      seekbar.setprogress(currentposition);
    }
  };

  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    verifystoragepermissions(mainactivity.this);
    //获取播放暂停按钮
    btpause_play=(button) findviewbyid(r.id.bt_pause);
    intent intent=new intent(mainactivity.this,mymusicservice.class);
    bindservice(intent,new myconn(),bind_auto_create);
    seekbar=(seekbar) findviewbyid(r.id.seekbar);
    seekbar.setonseekbarchangelistener(new seekbar.onseekbarchangelistener() {
      @override
      public void onprogresschanged(seekbar seekbar, int progress, boolean fromuser) {
      }
      @override
      public void onstarttrackingtouch(seekbar seekbar) {
      }
      @override
      public void onstoptrackingtouch(seekbar seekbar) {
        try {
          imymusicservice.seekplayprogress(seekbar.getprogress());
        } catch (remoteexception e) {
          e.printstacktrace();
        }
      }
    });
  }
   //定义服务连接类
  class myconn implements serviceconnection{

    @override
    public void onserviceconnected(componentname name, ibinder service) {
      imymusicservice=imymusicservice.stub.asinterface(service);
    }
    @override
    public void onservicedisconnected(componentname name) {

    }
  }
  public void play(view v){
    try {
      imymusicservice.play();

    } catch (remoteexception e) {
      e.printstacktrace();
    }
  }

  public void pause(view v){
    try {
      if(b)
      {
       imymusicservice.pause();
        b=false;
        btpause_play.settext("继续播放");
      }
      else{
         b=true;
        imymusicservice.continueplay();
        btpause_play.settext("暂停播放");

      }

    } catch (remoteexception e) {
      e.printstacktrace();
    }
  }

  public void stop(view v){
    try {
        imymusicservice.stop();
    } catch (remoteexception e) {
      e.printstacktrace();
    }
  }
  // storage permissions
  private static final int request_external_storage = 1;
  private static string[] permissions_storage = {
      manifest.permission.read_external_storage,
      manifest.permission.write_external_storage,
  };

  /**
   * checks if the app has permission to write to device storage
   *
   * if the app does not has permission then the user will be prompted to grant permissions
   *
   * @param activity
   */
  public static void verifystoragepermissions(activity activity) {
    // check if we have write permission
    int permission = activitycompat.checkselfpermission(activity, manifest.permission.write_external_storage);

    if (permission != packagemanager.permission_granted) {
      // we don't have permission so prompt the user
      activitycompat.requestpermissions(
          activity,
          permissions_storage,
          request_external_storage
      );
    }
  }
} 

四.布局文件 

<?xml version="1.0" encoding="utf-8"?>
<relativelayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingleft="@dimen/activity_horizontal_margin"
  android:paddingright="@dimen/activity_horizontal_margin"
  android:paddingtop="@dimen/activity_vertical_margin"
  android:paddingbottom="@dimen/activity_vertical_margin"
  tools:context="my.com.mymusicp.mainactivity">

  <linearlayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignparenttop="true"
    android:layout_alignparentleft="true"
    android:layout_alignparentstart="true"
    android:id="@+id/linearlayout">

    <button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="开始播放"
      android:onclick="play"
      android:id="@+id/bt_start"/>

    <button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="暂停播放"
      android:layout_weight="1"
      android:onclick="pause"
      android:id="@+id/bt_pause"/>

    <button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="停止播放"
      android:onclick="stop"
      android:id="@+id/bt_stop"/>
  </linearlayout>

  <seekbar
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/seekbar"
    android:layout_below="@+id/linearlayout"
    android:layout_alignparentleft="true"
    android:layout_alignparentstart="true"/>

</relativelayout> 

五.注册服务 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="my.com.mymusicp">
<uses-permission android:name="android.permission.read_external_storage"/>
  <uses-permission android:name="android.permission.write_external_storage"/>
  <application
    android:allowbackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    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=".mymusicservice"/>
  </application>

</manifest>

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