添加代碼以從sqlite數據庫加載座標後，無法讀取行0，col -1從CursorWindow錯誤

Question

我正在創建一個具有imageButton建築物的用戶可以購買的應用程序。購買時，將它們放到用戶佈局中，然後進行拖放。當用戶移動建築物時，座標在被放下時會自動保存。我的問題是，在加載函數來加載座標後，我得到了我在我的logcat中發佈的錯誤。我已經多次看到這個問題，並嘗試過所有我沒有看到過的運氣。請幫助傢伙。謝謝。

這裏是我的列名：

public static final String KEY_ROWID = "_id"; 
public static final String KEY_ROCK = "amount_of_rock"; 
public static final String KEY_METEORROCK = "amount_of_meteor_rock"; 
public static final String KEY_WATER = "amount_of_water"; 
public static final String KEY_SHOVEL = "shovel_level"; 
public static final String KEY_SHOVELEXP = "shovel_experience"; 
public static final String KEY_BUCKET = "bucket_level"; 
public static final String KEY_BUCKETEXP = "bucket_experience"; 
public static final String KEY_PICKAXE = "pickaxe_level"; 
public static final String KEY_PICKAXEEXP = "pickaxe_experience"; 
public static final String KEY_POPULATION = "population"; 
public static final String KEY_MAINHUTLEVEL = "main_hut_level"; 
public static final String KEY_MAINHUTHEALTH = "main_hut_health"; 
public static final String KEY_MAINHUTX = "main_hut_x_coord"; 
public static final String KEY_MAINHUTY = "main_hut_y_ coord"; 

private static final String DATABASE_NAME = "2023db"; 
private static final String DATABASE_TABLE = "maintable"; 
private static final int DATABASE_VERSION = 1; 

這裏是我得到mainHut（發生的錯誤上的getMainHutY功能旁邊有一個註釋行）的保存座標代碼：

public float getMainHutX() 
{ 
    float mainHutX = 0; 
    int iMainHutX = 0; 
    String[] columns = new String[] {KEY_ROWID, KEY_ROCK, KEY_METEORROCK, KEY_WATER, 
      KEY_POPULATION, KEY_SHOVEL, KEY_BUCKET, KEY_PICKAXE, KEY_SHOVELEXP, 
      KEY_BUCKETEXP, KEY_PICKAXEEXP, KEY_MAINHUTLEVEL, KEY_MAINHUTHEALTH, 
      KEY_MAINHUTX, KEY_MAINHUTY}; 
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null); 

    if (c != null && c.getCount() > 0) 
    { 
     if (c.moveToFirst()) 
     { 
      iMainHutX = c.getColumnIndex(KEY_MAINHUTX); 
      mainHutX = c.getFloat(iMainHutX); 
     }//end if 
     c.close(); 
     return mainHutX; 
    }//end if 
    return 0; 
}//end getMainHutX function 

public float getMainHutY() 
{ 
    float mainHutY = 0; 
    int iMainHutY = 0; 
    String[] columns = new String[] {KEY_ROWID, KEY_ROCK, KEY_METEORROCK, KEY_WATER, 
      KEY_POPULATION, KEY_SHOVEL, KEY_BUCKET, KEY_PICKAXE, KEY_SHOVELEXP, 
      KEY_BUCKETEXP, KEY_PICKAXEEXP, KEY_MAINHUTLEVEL, KEY_MAINHUTHEALTH, 
      KEY_MAINHUTX, KEY_MAINHUTY}; 
    Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null); 

    if (c != null && c.getCount() > 0) 
    { 
     if (c.moveToFirst()) 
     { 
      iMainHutY = c.getColumnIndex(KEY_MAINHUTY); 
      mainHutY = c.getFloat(iMainHutY); //error occurs here 
     }//end if 
     c.close(); 
     return mainHutY; 
    }//end if 
    return 0; 
}//end getMainHutY function 

這裏是我的logcat：

10-02 22:32:18.036: E/CursorWindow(561): Failed to read row 0, column -1 from a CursorWindow which has 1 rows, 15 columns. 
10-02 22:32:18.036: E/AndroidRuntime(561): FATAL EXCEPTION: main 
10-02 22:32:18.036: E/AndroidRuntime(561): Process: com.twentytwentythree.sab, PID: 561 
10-02 22:32:18.036: E/AndroidRuntime(561): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.twentytwentythree.sab/com.project.llb.runGraphics}: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it. 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2596) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2653) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread.access$800(ActivityThread.java:156) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1355) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.os.Handler.dispatchMessage(Handler.java:102) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.os.Looper.loop(Looper.java:157) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread.main(ActivityThread.java:5872) 
10-02 22:32:18.036: E/AndroidRuntime(561): at java.lang.reflect.Method.invoke(Native Method) 
10-02 22:32:18.036: E/AndroidRuntime(561): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:852) 
10-02 22:32:18.036: E/AndroidRuntime(561): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:668) 
10-02 22:32:18.036: E/AndroidRuntime(561): 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. 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.database.CursorWindow.nativeGetDouble(Native Method) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.database.CursorWindow.getDouble(CursorWindow.java:597) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.database.CursorWindow.getFloat(CursorWindow.java:648) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.database.AbstractWindowedCursor.getFloat(AbstractWindowedCursor.java:81) 
10-02 22:32:18.036: E/AndroidRuntime(561): at com.twentytwentythree.sab.Database.getMainHutY(Database.java:228) 
10-02 22:32:18.036: E/AndroidRuntime(561): at com.twentytwentythree.sab.runGraphics.onCreate(runGraphics.java:142) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.Activity.performCreate(Activity.java:5312) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111) 
10-02 22:32:18.036: E/AndroidRuntime(561): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2552) 
10-02 22:32:18.036: E/AndroidRuntime(561): ... 9 more 

Answer 1

這將有助於如果你能證明什麼日e列名常量是（特別是對於KEY_MAINHUTY）。

在任何情況下，在查看完這些之後，唯一可以得出結論的是您正在查詢的表沒有具有由KEY_MAINHUTY指定的名稱的列。

你可以驗證你的表確實有一個由KEY_MAINHUTY指定的名稱的列嗎？

對c.getColumnIndex（KEY_MAINHUTY）的調用;正在返回-1，但該列名在您的列數組中明確指定。