java为什么我的程序在按下后退按钮时崩溃
[这是sd卡中歌曲的列表视图][1]
![][1]](http://i.stack.imgur.com/hr3Ik.png){kind=link}
****这是我的主要活动代码****
package com.example.jawad.musicplayer;
import 安卓.content.Intent;
import 安卓.media.MediaPlayer;
import 安卓.os.Environment;
import 安卓.support.v7.app.AppCompatActivity;
import 安卓.os.Bundle;
import 安卓.view.View;
import 安卓.widget.AdapterView;
import 安卓.widget.ListView;
import 安卓.widget.Toast;
import java.io.File;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity implements View.OnClickListener
{
ListView musicListView;
ArrayList<File> musicFiles;
MediaPlayer mediaplayer;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
musicListView = (ListView) findViewById(R.id.musiclistviewId);
musicFiles = findSongs(Environment.getExternalStorageDirectory());
CustomListViewAdapter CLV = new CustomListViewAdapter(MainActivity.this,R.layout.list_row,musicFiles);
musicListView.setAdapter(CLV);
musicListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
startActivity(new Intent(MainActivity.this,PlayerActivity.class).putExtra("music",musicFiles).putExtra("pos",position));
}
});
/*for (int i =0 ;i < music.size();i++)
{
toast(music.get(i).getName().toString());
}*/
}
public ArrayList<File> findSongs(File root)
{
File[] files = root.listFiles();
ArrayList<File> tempSongs = new ArrayList<>();
for(File singlefile : files)
{
if(singlefile.isDirectory() && !singlefile.isHidden())
{
tempSongs.addAll(findSongs(singlefile));
}
else
{
if(singlefile.getName().endsWith(".mp3"))
{
tempSongs.add(singlefile);
}
}
}
return tempSongs;
}
public void toast(String text)
{
Toast.makeText(getApplicationContext(),text,Toast.LENGTH_LONG).show();
}
@Override
public void onClick(View v) {
}
}
这是“玩家活动”的代码
package com.example.jawad.musicplayer;
import 安卓.media.MediaPlayer;
import 安卓.net.Uri;
import 安卓.support.v7.app.AppCompatActivity;
import 安卓.os.Bundle;
import 安卓.view.View;
import 安卓.widget.Button;
import 安卓.widget.SeekBar;
import 安卓.widget.Toast;
import java.io.File;
import java.util.ArrayList;
public class PlayerActivity extends AppCompatActivity implements View.OnClickListener
{
Button playButton;
MediaPlayer mplayer;
private Button prevButton;
private Button nextButton;
SeekBar sb;
Thread updateThread;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player);
playButton = (Button) findViewById(R.id.playButtonId);
prevButton=(Button) findViewById(R.id.prevButtonId);
nextButton = (Button) findViewById(R.id.nextButtonId);
sb = (SeekBar) findViewById(R.id.seekbarId);
playButton.setOnClickListener(this);
nextButton.setOnClickListener(this);
prevButton.setOnClickListener(this);
Bundle extra = getIntent().getExtras();
if(extra!=null) {
ArrayList<File> list = (ArrayList) extra.getParcelableArrayList("music");
int pos = extra.getInt("pos");
File file = list.get(pos);
// Toast.makeText(getApplicationContext(),file.getName().toString(),Toast.LENGTH_LONG).show();
Uri URI = Uri.parse(file.toString());
mplayer=MediaPlayer.create(getApplicationContext(),URI);
}
}
@Override
public void onClick(View v) {
int id =v.getId();
switch(id)
{
case R.id.playButtonId:
if(mplayer.isPlaying())
pauseMusic();
else
playMusic();
break;
case R.id.prevButtonId:
break;
case R.id.nextButtonId:
break;
}
}
public void playMusic()
{
if(mplayer!= null) {
mplayer.start();
playButton.setBackgroundDrawable(getResources().getDrawable(安卓.R.drawable.ic_media_pause));
updateThread = new Thread() {
@Override
public void run()
{
sb.setMax(mplayer.getDuration());
int toatalduration = mplayer.getDuration();
int currentposition = 0;
while (currentposition < toatalduration && mplayer.isPlaying())
{
try
{
sleep(500);
currentposition = mplayer.getCurrentPosition();
sb.setProgress(currentposition);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
};
}
updateThread.start();
}
@Override
public void onBackPressed() {
updateThread.stop();
onDestroy();
}
public void pauseMusic()
{
if (mplayer!=null)
{
mplayer.pause();
playButton.setBackgroundDrawable(getResources().getDrawable(安卓.R.drawable.ic_media_play));
}
}
@Override
protected void onDestroy() {
if(mplayer!=null && mplayer.isPlaying())
{
mplayer.stop();
mplayer.release();
mplayer = null;
super.onDestroy();
}
}
}
基本上，我对安卓编程还不熟悉，并在安卓上练习制作媒体播放器。我对Java有很好的掌握，但仍然无法找到这个问题的解决方案，因此欢迎您的帮助。 我还重写了onBackPressed（）方法，在该方法中，我停止了线程并停止了音乐播放器，但安卓 studio仍然给出了错误
这是我的日志：
08-15 14:11:00.721 1429-1429/com.example.jawad.musicplayer E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.jawad.musicplayer, PID: 1429
安卓.util.SuperNotCalledException: Activity {com.example.jawad.musicplayer/com.example.jawad.musicplayer.PlayerActivity} did not call through to super.onDestroy()
at 安卓.app.ActivityThread.performDestroyActivity(ActivityThread.java:3472)
at 安卓.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3501)
at 安卓.app.ActivityThread.access$1400(ActivityThread.java:135)
at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:1249)
at 安卓.os.Handler.dispatchMessage(Handler.java:102)
at 安卓.os.Looper.loop(Looper.java:136)
at 安卓.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
08-15 14:11:00.721 534-760/system_process W/ActivityManager: Force finishing activity com.example.jawad.musicplayer/.MainActivity
[08-15 14:11:00.741 534: 760 D/] HostConnection::get() New Host Connection established 0xb7cbc840, tid 760
# 1 楼答案
请尝试以下代码：