android音乐播放器拖放播放进度设计

android音乐播放器拖放播放进度设计

效果图：

[img]http://dl.iteye.com/upload/attachment/0066/5456/780b81ae-a6a5-3e0f-b87a-8d56401ee7d4.jpg[/img]

播放器设计中需要显示播放进度，并随着播放的进行，进度条要走动。当我们直接拖放播放进度条，也能调整播放进度。这里我们使用了SeekBar来完成这个任务。
下面直接上代码：

界面布局不多说
main.xml

    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >


            android:id="@+id/relativeLayout1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >


                    android:id="@+id/seekBar1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true" />

                    android:id="@+id/previous"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:text="前一个" />

                    android:id="@+id/next"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_alignParentRight="true"
            android:text="下一个" />

                    android:id="@+id/play"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_toLeftOf="@id/next"
            android:layout_toRightOf="@id/previous"
            android:text="播放" />


    

在前台的界面，只设置了播放操作，可以看到点击播放后，我们启动了service播放音乐，这里我们要注意看到SeekBarReceiver这个。我们是通过接收受service发过来的广播，并调整进度条的。还有这个SeekBarListener，我们通过它设置了SeekBar的拖放操作
MusicseekbarActivity.java

package org.hwq.music.seekbar;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class MusicseekbarActivity extends Activity implements OnClickListener{
	Button pre,play,next;
	SeekBar seekbar;
	SeekBarReceiver receiver;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        pre = (Button) findViewById(R.id.previous);
        play = (Button) findViewById(R.id.play);
        next = (Button) findViewById(R.id.next);
        seekbar = (SeekBar) findViewById(R.id.seekBar1);
        pre.setOnClickListener(this);
        play.setOnClickListener(this);
        next.setOnClickListener(this);
        seekbar.setOnSeekBarChangeListener(new SeekBarListener());
    }
    @Override
    protected void onStart() {
    	super.onStart();
    	//注册receiver接受service中发送过来的广播
    	receiver = new SeekBarReceiver();
    	this.registerReceiver(receiver, new IntentFilter("org.hwq.receiver.seekbar"));
    }
    @Override
    protected void onDestroy() {
    	super.onStop();
    	Intent intent = new Intent(this,PlayService.class);
    	stopService(intent);
    	PlayService.isrunning = false;
    	this.unregisterReceiver(receiver);
    	super.onDestroy();
    }
    //是否正在进行拖放（没设置这个的话，在拖放的过程中会出现点小小不爽的效果，自己可以测试下）
    boolean seekbarTrackTouch = false;
    //SeekBar拖放事件处理了
    class SeekBarListener implements OnSeekBarChangeListener{
		public void onProgressChanged(SeekBar seekBar, int progress,
				boolean fromUser) {

		}
		public void onStartTrackingTouch(SeekBar seekBar) {
			seekbarTrackTouch = true;
		}
		public void onStopTrackingTouch(SeekBar seekBar) {
			seekbarTrackTouch = false;
			int currentPosition = seekBar.getProgress();
			Intent intent = new Intent("org.hwq.music.seekbar.seekto");
			intent.putExtra("currentPosition", currentPosition);
			sendBroadcast(intent);
		}
    }
	public void onClick(View v) {
		switch(v.getId()){
		case R.id.previous:
			playPrevious();
			break;
		case R.id.play:
			play();
			break;
		case R.id.next:
			playNext();
			break;
		}
	}
	private void playNext() {

	}
	private void play() {
		System.out.println("play()被点击");
		Intent intent = new Intent(this,PlayService.class);
		intent.putExtra("op", "play");
		startService(intent);
	}
	private void playPrevious() {

	}
	class SeekBarReceiver extends BroadcastReceiver{
		@Override
		public void onReceive(Context context, Intent intent) {
			int currentPosition = intent.getIntExtra("currentPosition", 0);
			int duration = intent.getIntExtra("duration", 0);
			System.out.println("activity收到一个广播：currentPosition="+currentPosition+" duration="+duration);
			if(!seekbarTrackTouch){
				seekbar.setProgress(currentPosition*100/duration);
				seekbar.invalidate();
			}
		}
	}
}

播放service，播放过程中通过发出广播，影响前台的SeekBar的播放进度。并接收前台SeekBar的拖放事件广播，调整音乐播放进度。
PlayService.java

package org.hwq.music.seekbar;

import java.util.List;

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.net.Uri;
import android.os.Bundle;
import android.os.IBinder;

public class PlayService extends Service implements Runnable {
	private MediaPlayer player;
	private List musicList;
	private SeekbarReceiver receiver ;
	public static boolean isrunning = true;

	@Override
	public void onCreate() {
		player = new MediaPlayer();
		musicList = MusicList.getMusicData(this);
		new Thread(this).start();
		receiver = new SeekbarReceiver();
		registerReceiver(receiver, new IntentFilter("org.hwq.music.seekbar.seekto"));
	}
	@Override
	public IBinder onBind(Intent intent) {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public void onDestroy() {
		if(player != null){
			player.release();
			player = null;
		}
		unregisterReceiver(receiver);
		super.onDestroy();
	}

	@Override
	public void onStart(Intent intent, int startId) {
		Bundle extras = intent.getExtras();
		String op = extras.getString("op");
		if("play".equals(op)){
			play();
		}
	}

	private void play() {
		System.out.println("service中的play执行");
		Music m = musicList.get(0);
		Uri uri = Uri.parse(m.getUrl());
		try{
			player.setDataSource(this,uri);
			player.prepare();
			player.start();
		}catch (Exception e) {
			e.printStackTrace();
		}
	}
	public void run() {
		while(isrunning){
			try{
				Thread.sleep(100);
			}catch (Exception e) {

			}
			if(player!=null){
				int currentPosition = player.getCurrentPosition();
				int duration = player.getDuration();
				Intent intent = new Intent("org.hwq.receiver.seekbar");
				intent.putExtra("currentPosition", currentPosition);
				intent.putExtra("duration", duration);
				System.out.println("发出一个广播：currentPosition="+currentPosition);
				sendBroadcast(intent);
			}
		}
	}
	//接收前台拖放的进度，并调整歌曲的播放进度
	class SeekbarReceiver extends BroadcastReceiver{
		public void onReceive(Context context, Intent intent) {
			int currentPosition = intent.getIntExtra("currentPosition", 0);
			System.out.println("seekbar拖放了currentPosition="+currentPosition);
			player.seekTo(player.getDuration()*currentPosition/100);
			player.start();
		}
	}
}

大致就讲完。这里想起一个网上看到的题目，没有activity，能否启动一个运用。答案是可以的：首先，我们得添加权限 ，然后注册一个receiver侦听，并在receiver来启动一个service或一个activity就ok了。

下面是这个demo：