java - 自己制作一个视频播放器，遇到问题，用的是内置surfaceview类，具体看代码！

问题描述

public class Main_activity extends AppCompatActivity { private ImageButton button; @Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);button=(ImageButton) findViewById(R.id.imageButton);button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {Intent intent=new Intent(Main_activity.this,MyListView.class);startActivity(intent); }}); }}

public class MyListView extends AppCompatActivity { private ListView listView; private List<String> data = new ArrayList<String>(); @Override public void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);listView = new ListView(this);data=getData();listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,data));setContentView(listView);listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) {Intent intent=new Intent(MyListView.this,Surfaceview.class);intent.putExtra('datap',data.get(position));startActivity(intent);finish(); }}); } private List<String> getData(){List<String> data = new ArrayList<String>();ContentResolver c=getContentResolver();Cursor cur = c.query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, null,null, null,null);int num=cur.getCount();cur.moveToFirst();for (int i=0;i<num;i++){ String datapath=cur.getString(cur.getColumnIndex(MediaStore.Video.Media.DATA)); data.add(datapath); cur.moveToNext();}return data; }}

public class Surfaceview extends AppCompatActivity { MediaPlayer mp; SurfaceView sv; Handler mHandler; Runnable mRunnable; @Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.surfacexml);Intent intent=this.getIntent();final String datapath=intent.getStringExtra('datap');sv=(SurfaceView)findViewById(R.id.surfaceView2);final LinearLayout linearLayout=(LinearLayout)findViewById(R.id.test);mp=new MediaPlayer();final Button bplay=(Button)findViewById(R.id.play);Button bbefore=(Button)findViewById(R.id.before);Button bnext=(Button)findViewById(R.id.next);final SeekBar seekbar=(SeekBar)findViewById(R.id.seekbar); sv.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { mHandler.removeCallbacks(mRunnable); linearLayout.setVisibility(View.VISIBLE); mHandler.postDelayed(mRunnable,4000); return false; } });mHandler= new Handler();mRunnable = new Runnable() { @Override public void run() {linearLayout.setVisibility(View.INVISIBLE); }};try { mp.setDataSource(datapath);} catch (IOException e) { e.printStackTrace();}mp.setDisplay(sv.getHolder());try { mp.prepare();} catch (IOException e) { e.printStackTrace();}mp.start();Timer timer=new Timer();timer.schedule(new TimerTask() { @Override public void run() {float x=mp.getDuration();float i=mp.getCurrentPosition();float p=i/x*100;int g=(int)p; seekbar.setProgress(g); }},0, 500);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) { float x=seekBar.getProgress();float a=mp.getDuration();float i=x/100*a;int j=(int)i;mp.pause();mp.seekTo(j);mp.start(); }});bplay.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (mp.isPlaying()) { mp.pause(); bplay.setText('play'); } else { mp.start(); bplay.setText('pause'); } }}); }}

以上是3个主类，我的思路是主页面一个按钮，然后点击就进入MyListView，就是用list类现实本机里所有视频文件，然后点击一个item，在进入Surfaceview，这是主播放的界面，但是前面都还好，就是最后这个surface进不去，我在努力思考原因，各种调试，但是还是没找出原因，错误如下：

E/AndroidRuntime: FATAL EXCEPTION: main Process: yuyu.mymedia, PID: 2524 java.lang.RuntimeException: Unable to start activity ComponentInfo{yuyu.mymedia/yuyu.mymedia.Surfaceview}: java.lang.IllegalArgumentException: The surface has been released at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2947) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3008) at android.app.ActivityThread.-wrap14(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6688) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) Caused by: java.lang.IllegalArgumentException: The surface has been released at android.media.MediaPlayer._setVideoSurface(Native Method) at android.media.MediaPlayer.setDisplay(MediaPlayer.java:795) at yuyu.mymedia.Surfaceview.onCreate(Surfaceview.java:66) at android.app.Activity.performCreate(Activity.java:6912) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1126) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2900) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3008) at android.app.ActivityThread.-wrap14(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1650) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6688)

然后调试的时候，当运行到sv.setOnTouchListener(new View.OnTouchListener()这句以及后面的mp,handle等，会出现没有sv,mp,这些的实例，十分不理解，怎么会没有实例？

问题解答

会不会是surfaceHolder还没准备好的时候，就调用了MediaPlayer的start()方法。

自己顶一下，怎么没有人。。。