android - Android ExceptionInitializerError

Question

我在以下代码行中收到“ExceptionInitializerError”：

（活动一）

Activity2.selection = AudioColumns.ARTIST + "=?";

（活动二）

static String selection;

有人可以告诉我我做错了什么吗？

有关完整代码，请参见下文。

（活动一）

package awesome.music.player;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.BaseColumns;
import android.provider.MediaStore;
import android.provider.MediaStore.Audio.AlbumColumns;
import android.provider.MediaStore.Audio.ArtistColumns;
import android.provider.MediaStore.Audio.AudioColumns;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class ArtistsActivity extends Activity implements OnItemClickListener {

    private Cursor artistCursor;

    @SuppressWarnings("deprecation")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.artistsview);

        String[] artistColumns = { BaseColumns._ID, ArtistColumns.ARTIST };
        // The columns to return for each row.

        artistCursor = managedQuery(
                MediaStore.Audio.Artists.EXTERNAL_CONTENT_URI, artistColumns,
                null, null, null);

        ListView listView = (ListView) findViewById(R.id.listViewArtists);
        listView.setOnItemClickListener(this);
        // set an on item click listener to the first list view in this activity

        String[] displayFields = new String[] { ArtistColumns.ARTIST };
        // set all the artist names to the array "displayfields"
        int[] displayViews = new int[] { R.id.artistTitle };
        // number of rows to display and where to bind them

        SimpleCursorAdapter artistAdapter = new SimpleCursorAdapter(this,
                R.layout.artistitem, artistCursor, displayFields, displayViews);
        listView.setAdapter(artistAdapter);
    }

    // Take the display fields array, and bind to the matching display row

    public void onItemClick(AdapterView<?> a, View v, int position, long id) {
        if (artistCursor.moveToPosition(position)) {

            Playlist.selection = AudioColumns.ARTIST + "=?";

            Playlist.selectionArgs = new String[] { artistCursor
                    .getString(artistCursor.getColumnIndex(AlbumColumns.ARTIST)) };

            Playlist.artist = artistCursor.getString(artistCursor
                    .getColumnIndex(ArtistColumns.ARTIST));

            Intent intent = new Intent(ArtistsActivity.this,
                    ArtistAlbumsActivity.class);

            startActivity(intent);

        }
    }

}

（活动二）

package awesome.music.player;

import java.util.ArrayList;

import android.content.ContentUris;
import android.net.Uri;

public class Playlist {

    static ArrayList<String> pathList = new ArrayList<String>();
    static ArrayList<String> artistList = new ArrayList<String>();
    static ArrayList<String> albumList = new ArrayList<String>();
    static ArrayList<String> titleList = new ArrayList<String>();
    static ArrayList<String> idList = new ArrayList<String>();
    static ArrayList<String> durationList = new ArrayList<String>();

    static int currentSongIndex;
    static String currentSongPath;
    static String artist;
    static String album;
    static String albumId;
    static String numSongs;
    static String selection;
    static String[] selectionArgs;
    static String totalSongduration; // Set

    static String songDuration = durationList.get(currentSongIndex);

    static String currentAlbumId = Playlist.idList
            .get(Playlist.currentSongIndex);

    static Integer currentAlbumIdLong = Integer.parseInt(currentAlbumId);

    static Uri artworkUri = Uri
            .parse("content://media/external/audio/albumart");

    static Uri currentSongUri = ContentUris.withAppendedId(artworkUri,
            currentAlbumIdLong);;

    static int totalSongDuration = Integer.parseInt(songDuration);

}

谢谢你的帮助。

score 1 · Accepted Answer

抛出 ExceptionInInitializerError 以指示在评估静态初始化程序或静态变量的初始化程序期间发生异常。检查您的代码是否有任何静态初始化逻辑。

score 0 · Accepted Answer

不要使用Static它是一个坏习惯，而是使用“静态”使一个对象成为类并使用它。

public class Playlist {

    ArrayList<String> pathList = new ArrayList<String>();
....
...
}

实施。

public class ArtistsActivity extends Activity implements OnItemClickListener {

    private Playlist mPlaylist;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.artistsview);
        mPlaylist= new Playlist();
     }
}

score 0 · Accepted Answer

检查处的静态初始化Playlist，就像Integer.parseInt(currentAlbumId);在初始化处currentAlbumId有null值一样。

android - Android ExceptionInitializerError

3 回答 3

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