SQLite高分数据库，illegalStateException - Android（java）

我做了一个SQLite高分，有3列; id（int - autoincrement），分数（long）和百分比（int）。我试图从列中提取所有数据，并将它们与用户刚刚看到的分数进行比较，看看他们的新分数是否成为排名前十的高分榜。SQLite高分数据库，illegalStateException - Android（java）

我想按百分比优先考虑高分首先，然后打分打破任何关系。下面是我开始这样做的地方。我甚至从来没有在Java之外使用过SQLite，所以这对我来说都是全新的。我收到一个错误。 LogCat在下面。

非常感谢您的帮助。

//Check if new record makes the top 10. 
public boolean check(long score, int percentage) { 
    Cursor c1 = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + " WHERE " + PERCENTAGE + "= percentage;", null); 
    Cursor c2 = db.rawQuery("SELECT " + SCORE + " FROM " + TABLE + ";", null); 
    if(c1.getCount() > 0) {    
     c2.moveToFirst(); 
     int i = 0; 
     do { 
      i++; 
      long x = c2.getLong(c2.getColumnIndex("SCORE")); //Line 39 
      if(x < percentage) { 
       if(c2.getCount() == 9) { 
        //Delete last record in high score and insert at index. 
        db.rawQuery("DELETE FROM " + TABLE + " WHERE " + ID + " = 10;", null); 
        db.rawQuery("INSERT INTO " + TABLE + "VALUES (" + i + ", " + score + ", " + percentage + ");", null); 
        return true; 
       } else { 
        //No deletion - just insert. 
        db.rawQuery("INSERT INTO " + TABLE + "VALUES (" + i + ", " + score + ", " + percentage + ");", null); 
        return true; 
       } 
      } else { 
       return false; 
      } 
     } while (c2.moveToNext()); 
    } else { 
     return false; 
    } 
}

logcat的输出

12-19 02:26:45.270: E/AndroidRuntime(24809): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.Results}: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it. 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread.access$600(ActivityThread.java:130) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.os.Handler.dispatchMessage(Handler.java:99) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.os.Looper.loop(Looper.java:137) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread.main(ActivityThread.java:4745) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at java.lang.reflect.Method.invokeNative(Native Method) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at java.lang.reflect.Method.invoke(Method.java:511) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at dalvik.system.NativeStart.main(Native Method) 
12-19 02:26:45.270: E/AndroidRuntime(24809): Caused by: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it. 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.database.CursorWindow.nativeGetLong(Native Method) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.database.CursorWindow.getLong(CursorWindow.java:507) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.database.AbstractWindowedCursor.getLong(AbstractWindowedCursor.java:75) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at com.example.test.DatabaseHelper.check(DatabaseHelper.java:39) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at com.example.test.Results.showResults(Results.java:102) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at com.example.test.Results.onCreate(Results.java:51) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.Activity.performCreate(Activity.java:5008) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
12-19 02:26:45.270: E/AndroidRuntime(24809): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)

如果你看到，一旦问题得到解决的算法可能会无法正常工作，我就明白，是指出了！先进的谢谢你。

来源

2012-12-27 Matt

您的光标1查询是不正确，请尝试以下，

Cursor c1 = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + " WHERE " + PERCENTAGE + "=" + percentage, null);

你也应该做一个空检查你的光标在使用前，以及关闭它们当你完成：

if (c1 != null && c2 != null) 
{ 
    // Do your thing 
    /* Stuff */ 

    // Now close the cursors 
    c1.close(); 
    c2.close(); 
}

来源

2012-12-27 19:43:25 Ralgha

一切工作，并感谢您的建议将光标空校验。我已经实现了。 – Matt

变化

Cursor c1 = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + 
           " WHERE " + PERCENTAGE + "= percentage;", null);

到

Cursor c1 = db.rawQuery("SELECT " + PERCENTAGE + " FROM " + TABLE + 
           " WHERE " + PERCENTAGE + "="+ percentage, null);

目前你不及格百分比WHERE子句

来源

2012-12-27 19:43:30

您得到异常的原因是要检查如果c1有内部因素（c1.getCount（）> 0），然后使用C2可能为空并且不检查c2.moveToFirst（）是否不返回false。

http://developer.android.com/reference/android/database/Cursor.html#moveToFirst（）

来源

2012-12-27 19:44:11 Raanan

SQLite高分数据库，illegalStateException - Android（java）

回答

相关问题