Question

我无法获得我的SQLite列的总和。该应用程序不断崩溃。任何帮助将不胜感激，谢谢=）。这是我在DatabaseHelper和Main Activity中的代码：

public class DatabaseOperator {
    private DataManager dataManager;
...
    public int getTotalExpenses()
{
    SQLiteDatabase database = dataManager.getReadableDatabase();
    Cursor cursor = database.rawQuery("SELECT SUM(" + Integer.valueOf(Expenses.C_TOTAL_PRICE) + ") FROM " + Expenses.TABLE, null);
    cursor.moveToFirst();
    int i = cursor.getInt(0);
    cursor.close();
    return i;
}

//MainActivity.class
TextView textTotalExpenses;
int totalExpenses;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

DatabaseOperator databaseOperator = new DatabaseOperator(this);
textTotalExpenses = (TextView) findViewById(R.id.textTotalExpenses);
totalExpenses = databaseOperator.getTotalExpenses();
textTotalExpenses.setText(totalExpenses);

03-26 09:31:23.483 5818-5818 / com.example.everydaybudgeting20 E / AndroidRuntime：FATAL EXCEPTION：main 处理：com.example.everydaybudgeting20，PID：5818 java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.everydaybudgeting20 / com.example.everydaybudgeting20.MainActivity}：java.lang.NumberFormatException：对于输入字符串：“totalPrice” 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2665）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2726）在android.app.ActivityThread.-wrap12（ActivityThread.java）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1477）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:154）在android.app.ActivityThread.main（ActivityThread.java:6119） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:886）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:776）引起：java.lang.NumberFormatException：对于输入字符串：“totalPrice” 在java.lang.Integer.parseInt（Integer.java:521）在java.lang.Integer.valueOf（Integer.java:611） at com.example.everydaybudgeting20.DatabaseOperator.getTotalExpenses（DatabaseOperator.java:229）在com.example.everydaybudgeting20.MainActivity.onCreate（MainActivity.java:76）在android.app.Activity.performCreate（Activity.java:6679）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1118）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2618）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2726）在android.app.ActivityThread.-wrap12（ActivityThread.java）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1477）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:154）在android.app.ActivityThread.main（ActivityThread.java:6119） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:886）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:776）

Answer 1

我自己修好了。谢谢你的帮助！

    public int getTotalExpenses()
{
    int total = 0;
    SQLiteDatabase database = dataManager.getReadableDatabase();
    Cursor cursor = database.rawQuery("SELECT SUM("+ Expenses.C_TOTAL_PRICE + ") FROM " + Expenses.TABLE, null);
    if (cursor.moveToFirst())
    {
        total = cursor.getInt(0);
    }
    while (cursor.moveToNext());
    return total;
}

Android SQLite列总和

1 个答案: