Question

我的音乐播放器应用程序是为Android 2.3.3制作的。这是很久以前的事了，所以我的掌握现在已经生疏了。当我尝试在新的OS 4.4.4上运行时，它会崩溃。

这是我的logcat：

09-05 01:44:39.460: E/AndroidRuntime(10855): FATAL EXCEPTION: main
09-05 01:44:39.460: E/AndroidRuntime(10855): Process: com.android.finalmediaplayer, PID: 10855
09-05 01:44:39.460: E/AndroidRuntime(10855): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.finalmediaplayer/com.android.finalmediaplayer.MusicPlayer}: java.lang.NullPointerException
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread.access$800(ActivityThread.java:135)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.os.Handler.dispatchMessage(Handler.java:102)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.os.Looper.loop(Looper.java:136)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread.main(ActivityThread.java:5001)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at java.lang.reflect.Method.invokeNative(Native Method)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at java.lang.reflect.Method.invoke(Method.java:515)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at dalvik.system.NativeStart.main(Native Method)
09-05 01:44:39.460: E/AndroidRuntime(10855): Caused by: java.lang.NullPointerException
09-05 01:44:39.460: E/AndroidRuntime(10855):    at com.android.finalmediaplayer.MusicPlayer.updateSongList(MusicPlayer.java:48)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at com.android.finalmediaplayer.MusicPlayer.onCreate(MusicPlayer.java:43)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.Activity.performCreate(Activity.java:5231)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
09-05 01:44:39.460: E/AndroidRuntime(10855):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
09-05 01:44:39.460: E/AndroidRuntime(10855):    ... 11 more

这是MusicPlayer.java的代码

package com.android.finalmediaplayer;

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.app.ListActivity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.DeadObjectException;
import android.os.IBinder;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;

class Mp3Filter implements FilenameFilter {
    public boolean accept(File dir, String name) {
        return (name.endsWith(".mp3"));
    }
}

public class MusicPlayer extends ListActivity {

    public static final String MEDIA_PATH = new String("/sdcard/");
    public List<String> songs = new ArrayList<String>();
    public MediaPlayer mp = new MediaPlayer();
    public String selectd;



    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.songlist);
            updateSongList();
            }

    public void updateSongList() {
        File home = new File(MEDIA_PATH);
        if (home.listFiles(new Mp3Filter()).length > 0) {
                for (File file : home.listFiles(new Mp3Filter())) {
                        songs.add(file.getName());
                }

                ArrayAdapter<String> songList = new ArrayAdapter<String>(this,
                                R.layout.song_item, songs);

                setListAdapter(songList);

        }
}

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {

            selectd = MEDIA_PATH + songs.get(position);    

            Intent nwIntent = new Intent (this, NowMusicPlay.class);
            nwIntent.putExtra("ComingFrom", selectd);
            nwIntent.putStringArrayListExtra("allSongs",(ArrayList<String>) songs);
            nwIntent.putExtra("pos", position);
            startActivityForResult(nwIntent, 0);




}
}

此代码用于扫描SD卡上的文件并列出它们。很简单，但现在它不适用于最新的Android版本。是否与新API有关？

请帮忙！如果需要，我可以提供更多代码片段。感谢。

我的android应用程序在kitkat上崩溃了

0 个答案: