为啥当我按下返回按钮时我的程序崩溃

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【中文标题】为啥当我按下返回按钮时我的程序崩溃【英文标题】:Why my program crash when i press back Button为什么当我按下返回按钮时我的程序崩溃 【发布时间】:2016-12-21 23:39:30 【问题描述】:

[这是sd卡中歌曲的列表视图][1]

****这是我的 MainActivity 代码****

package com.example.jawad.musicplayer;

import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.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 android.media.MediaPlayer;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.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(android.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(android.R.drawable.ic_media_play));
         
    

    @Override
    protected void onDestroy() 
        if(mplayer!=null && mplayer.isPlaying())
        
            mplayer.stop();
            mplayer.release();
            mplayer = null;
            super.onDestroy();
        
    

基本上我是 android 编程的新手,并练习在 android 中构建媒体播放器。我对 Java 有很好的掌握,但我仍然无法找到这个问题的解决方案,所以欢迎你的帮助。 我还重写了 onBackPressed() 方法,在该方法中我停止线程并停止音乐播放器,但仍然 android studio 给我错误。

这是我的 LogCat:

08-15 14:11:00.721 1429-1429/com.example.jawad.musicplayer E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.jawad.musicplayer, PID: 1429
android.util.SuperNotCalledException: Activity com.example.jawad.musicplayer/com.example.jawad.musicplayer.PlayerActivity did not call through to super.onDestroy()
 at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3472)
 at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3501)
 at android.app.ActivityThread.access$1400(ActivityThread.java:135)
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1249)
 at android.os.Handler.dispatchMessage(Handler.java:102)
 at android.os.Looper.loop(Looper.java:136)
 at android.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.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
 at com.android.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

【问题讨论】:

你读过错误吗? “android.util.SuperNotCalledException: Activity com.example.jawad.musicplayer/com.example.jawad.musicplayer.PlayerActivity 没有调用 super.onDestroy() 我真的建议您(和其他新用户)首先使用调试器并尝试逐步找出您的问题并查看具体内容,而不是来到这里并进行大量代码/logcat 转储 永远不要打电话给Thread.stop() 【参考方案1】:

试试下面的代码:

@Override
protected void onDestroy() 
    if(mplayer!=null && mplayer.isPlaying())
    
        mplayer.stop();
        mplayer.release();
        mplayer = null;
    
    super.onDestroy();

【讨论】:

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