从表中获取数据的麻烦

Question

当用户添加相册时，它会显示在ListView。假设你选择了用户写的情歌专辑

歌曲名称和标题并保存到歌曲表(songid,albumid,songname,songtitle)。

从我使用的歌曲表中获取歌曲

public ArrayList<Alldata> getMyData(long id)    
{    
    ArrayList<Alldata> arrayList=new ArrayList<Alldata>();    
    Cursor c=db.query(DATABASE_TABLE_SONG, new String[]{KEY_SONG_ID,KEY_ALBUM_ID,KEY_SONG_NAME,KEY_SONG_TITEL}, KEY_ALBUM_ID+"="+id, null,null,null,null);    
    Alldata myDatas;

    while(c.moveToNext())
    {
        myDatas=new Alldata();
        myDatas.song_id=c.getLong(c.getColumnIndex(KEY_SONG_ID));           
        myDatas.album_id=c.getInt(c.getColumnIndex(KEY_ALBUM_ID));          
        myDatas.song_name=c.getString(c.getColumnIndex(KEY_SONG_NAME)).trim();          
        myDatas.song_title=c.getString(c.getColumnIndex(KEY_SONG_TITEL)).trim();            

        arrayList.add(myDatas);
    }
    c.close();      
    return arrayList;       
}    

public void onClick(View v)    
{
   Alldata data=new Alldata();    
   AlbumDAO albumDAO=new AlbumDAO(SongActivity.this);    
   albumDAO.open();    
   ArrayList<Alldata> mydata=albumDAO.getMyData(albumid);    
   data=mydata.get(albumid);    
   Log.v("data.getAlbum_id()",data.getAlbum_id()+"");               

    albumDAO.close();
    }
});

//////////////////////////////////////////////////////////////////////////

02-06 18:07:37.948: ERROR/AndroidRuntime(27144): Uncaught handler: thread main exiting due to uncaught exception
02-06 18:07:38.069: ERROR/AndroidRuntime(27144): java.lang.IndexOutOfBoundsException: Invalid location 1, size is 0
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at java.util.ArrayList.get(ArrayList.java:341)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at krishna.ActionClass.SongActivity$2.onClick(SongActivity.java:79)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.View.performClick(View.java:2364)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.View.onTouchEvent(View.java:4179)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.widget.TextView.onTouchEvent(TextView.java:6541)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.View.dispatchTouchEvent(View.java:3709)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.app.Activity.dispatchTouchEvent(Activity.java:2061)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1691)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.os.Looper.loop(Looper.java:123)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at android.app.ActivityThread.main(ActivityThread.java:4363)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at java.lang.reflect.Method.invokeNative(Native Method)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at java.lang.reflect.Method.invoke(Method.java:521)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
02-06 18:07:38.069: ERROR/AndroidRuntime(27144):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您的数据库似乎返回 0 行，请尝试将您的 while 循环包装在 if(c.moveToFirst()) 中

if(c.moveToFirst())
{
while(c.moveToNext())
    {
        myDatas=new Alldata();
        myDatas.song_id=c.getLong(c.getColumnIndex(KEY_SONG_ID));           
        myDatas.album_id=c.getInt(c.getColumnIndex(KEY_ALBUM_ID));          
        myDatas.song_name=c.getString(c.getColumnIndex(KEY_SONG_NAME)).trim();          
        myDatas.song_title=c.getString(c.getColumnIndex(KEY_SONG_TITEL)).trim();            
        arrayList.add(myDatas);
    }
}