Question

嗨，我正在尝试在这里建立一个大学项目，以及一个提取和存款和账户的跟踪器。我试图添加一个整数到这个Android数据库，但每次我尝试这样做程序崩溃。数据库只包含1列，看起来像这样。

总

10

14

25

-24

50

package com.example.app;



import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

public class MainActivity extends Activity {
    String total;
    SQLiteDatabase db;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        db=openOrCreateDatabase("MyDB1",MODE_PRIVATE, null);
        db.execSQL("CREATE TABLE IF NOT EXISTS DepWith(total VARCHAR);");
    }
    public void data(View view)
    {
        EditText edittext1;
        edittext1 = (EditText)findViewById(R.id.Deposit);
        total=edittext1.getText().toString();

        db.execSQL("INSERT INTO DepWith VALUES('"+total+"');");


    }
    public void showdata(View view)
    {
        Cursor c=db.rawQuery("SELECT * from DepWith", null);
        int count= c.getCount();
        c.moveToFirst();
        TableLayout tableLayout = new TableLayout(getApplicationContext());
        tableLayout.setVerticalScrollBarEnabled(true);
        TableRow tableRow;
        TextView textView,textView1,textView2,textView3,textView4,textView5;
        tableRow = new TableRow(getApplicationContext());
        textView=new TextView(getApplicationContext());
        textView.setText("Total");
        textView.setTextColor(Color.RED);
        textView.setTypeface(null, Typeface.BOLD);
        textView.setPadding(20, 20, 20, 20);
        tableRow.addView(textView);
        tableLayout.addView(tableRow);
        for (Integer j = 0; j < count; j++)
        {
            tableRow = new TableRow(getApplicationContext());
            textView1 = new TextView(getApplicationContext());
            textView1.setText(c.getString(c.getColumnIndex("total")));

            textView1.setPadding(20, 20, 20, 20);

            tableRow.addView(textView1);

            tableLayout.addView(tableRow);
            c.moveToNext() ;
        }
        setContentView(tableLayout);
        db.close();
    }
    public void close(View view)
    {
        System.exit(0);
    }
}

继承我得到的错误

java.lang.IllegalStateException: Could not execute method of the activity
            at android.view.View$1.onClick(View.java:3823)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.reflect.InvocationTargetException
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at android.view.View$1.onClick(View.java:3818)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)
     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.
            at android.database.CursorWindow.nativeGetString(Native Method)
            at android.database.CursorWindow.getString(CursorWindow.java:434)
            at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
            at com.example.app.MainActivity.showdata(MainActivity.java:60)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at android.view.View$1.onClick(View.java:3818)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

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.
        at android.database.CursorWindow.nativeGetString(Native Method)
        at android.database.CursorWindow.getString(CursorWindow.java:434)
        at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
        at com.example.app.MainActivity.showdata(MainActivity.java:60)

这来自这里：

textView1.setText(c.getString(c.getColumnIndex("total")));

光标没有列total，getColumnIndex()返回-1。尝试获取第-1列值会导致此异常。

查看您的CREATE TABLE，您似乎在那里有列名，因此SELECT *应该返回它。如果您最近更改了列名称，请卸载您的应用程序，以便删除任何旧的数据库文件。如果已存在具有给定名称的表，则IF NOT EXISTS会使表创建成为无操作。

插入到Android数据库中

1 个答案: