前面文章已经详细介绍了Android界面的入门技术,相信大家在看完和跟着练习之后,会对于常用的Layout和View都会有一定的了解了,接下来就不再强调介绍界面了,而是针对具体的常见功能而展开。
本文将介绍MediaPlayer的使用。MediaPlayer可以播放音频和视频,另外也可以通过VideoView来播放视频,
虽然VideoView比MediaPlayer简单易用,但定制性不如用MediaPlayer,这需要视情况选择。MediaPlayer播放音频比较简单,但是要播放视频就需要SurfaceView。SurfaceView比普通的自定义View更有绘图上的优势,它支持完全的OpenGL ES库。
先贴出本文程序运行结果的截图,上面是播放/停止音频,可用SeekBar来调进度,下面是播放/停止视频,也是用SeekBar来调进度:
main.xml的源码如下:
<?xml version="1.0" encoding="utf-8"?><LinearLayout android:id="@+id/LinearLayout01" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical"> <SeekBar android:id="@+id/SeekBar01" android:layout_height="wrap_content" android:layout_width="fill_parent"></SeekBar> <LinearLayout android:id="@+id/LinearLayout02" android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:id="@+id/Button01" android:layout_width="wrap_content"android:layout_height="wrap_content" android:text="播放音频"></Button> <Button android:id="@+id/Button02" android:layout_width="wrap_content"android:layout_height="wrap_content" android:text="停止播放"></Button> </LinearLayout> <SeekBar android:id="@+id/SeekBar02" android:layout_height="wrap_content" android:layout_width="fill_parent"></SeekBar> <SurfaceView android:id="@+id/SurfaceView01" android:layout_width="fill_parent" android:layout_height="250px"></SurfaceView> <LinearLayout android:id="@+id/LinearLayout02" android:layout_width="wrap_content" android:layout_height="wrap_content"> <Button android:layout_width="wrap_content"android:layout_height="wrap_content" android:id="@+id/Button03"android:text="播放视频"></Button> <Button android:layout_width="wrap_content"android:layout_height="wrap_content" android:text="停止播放" android:id="@+id/Button04"></Button> </LinearLayout></LinearLayout>
Java部分源码有点长,需要大家耐心解读,详细程序如下:
package com.testMedia;import java.io.IOException; import java.util.Timer;import java.util.TimerTask;import android.app.Activity; import android.media.AudioManager;import android.media.MediaPlayer;import android.os.Bundle; import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.View; import android.widget.Button; import android.widget.SeekBar;import android.widget.Toast; public class testMedia extends Activity {/** Called when the activity is first created. */private SeekBar skb_audio=null;private Button btn_start_audio = null; private Button btn_stop_audio = null;private SeekBar skb_video=null;private Button btn_start_video = null; private Button btn_stop_video = null;private SurfaceView surfaceView; private SurfaceHolder surfaceHolder; private MediaPlayer m = null; private Timer mTimer;private TimerTask mTimerTask;private boolean isChanging=false;//互斥变量,防止定时器与SeekBar拖动时进度冲突 @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //----------Media控件设置---------//m=new MediaPlayer();//播放结束之后弹出提示m.setOnCompletionListener(new MediaPlayer.OnCompletionListener(){@Overridepublic void onCompletion(MediaPlayer arg0) {Toast.makeText(testMedia.this, "结束", 1000).show();m.release();}}); //----------定时器记录播放进度---------//mTimer = new Timer();mTimerTask = new TimerTask() {@Overridepublic void run() {if(isChanging==true) return;if(m.getVideoHeight()==0) skb_audio.setProgress(m.getCurrentPosition()); elseskb_video.setProgress(m.getCurrentPosition());}};mTimer.schedule(mTimerTask, 0, 10); btn_start_audio = (Button) this.findViewById(R.id.Button01); btn_stop_audio = (Button) this.findViewById(R.id.Button02); btn_start_audio.setOnClickListener(new ClickEvent());btn_stop_audio.setOnClickListener(new ClickEvent());skb_audio=(SeekBar)this.findViewById(R.id.SeekBar01);skb_audio.setOnSeekBarChangeListener(new SeekBarChangeEvent());btn_start_video = (Button) this.findViewById(R.id.Button03); btn_stop_video = (Button) this.findViewById(R.id.Button04); btn_start_video.setOnClickListener(new ClickEvent());btn_stop_video.setOnClickListener(new ClickEvent());skb_video=(SeekBar)this.findViewById(R.id.SeekBar02);skb_video.setOnSeekBarChangeListener(new SeekBarChangeEvent());surfaceView = (SurfaceView) findViewById(R.id.SurfaceView01);surfaceHolder = surfaceView.getHolder();surfaceHolder.setFixedSize(100, 100);surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);}/** 按键事件处理*/ class ClickEvent implements View.OnClickListener{ @Override public void onClick(View v) { if(v==btn_start_audio) {m.reset();//恢复到未初始化的状态m=MediaPlayer.create(testMedia.this, R.raw.big);//读取音频skb_audio.setMax(m.getDuration());//设置SeekBar的长度try { m.prepare(); //准备} catch (IllegalStateException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} m.start(); //播放 } else if(v==btn_stop_audio || v==btn_stop_video) {m.stop(); } else if(v==btn_start_video) {m.reset();//恢复到未初始化的状态m=MediaPlayer.create(testMedia.this, R.raw.test);//读取视频skb_video.setMax(m.getDuration());//设置SeekBar的长度m.setAudioStreamType(AudioManager.STREAM_MUSIC);m.setDisplay(surfaceHolder);//设置屏幕try {m.prepare();} catch (IllegalArgumentException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalStateException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}m.start(); } } } /** SeekBar进度改变事件*/ class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener{ @Override public void onProgressChanged(SeekBar seekBar, int progress,boolean fromUser) { // TODO Auto-generated method stub } @Override public void onStartTrackingTouch(SeekBar seekBar) { isChanging=true; } @Override public void onStopTrackingTouch(SeekBar seekBar) { m.seekTo(seekBar.getProgress()); isChanging=false;} }}
希望本文所述关于MediaPlayer的使用能对大家有所帮助。