android中的db.execsql失败了，我已经筋疲力尽了

Question

我程序中的SQLite查询失败。我不知道为什么。更神秘的是，我设法导出数据库并尝试在我的计算机上运行相同的SQLite查询，并且工作正常。

这是我的计划中的SQLite数据库：https://www.dropbox.com/s/tvz14rrgzufu5fy/backupname.db?dl=0

以下是查询：

UPDATE Log SET Productivity = 5 WHERE Time = 2523;

这是Android程序的Java代码：

    import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RatingBar;

import org.joda.time.LocalDateTime;


public class TimeRecorder extends Activity {
    int Year, Month, Day, Hour;
    private SQLiteDatabase db;
    private DatabaseHelper dbh;
    Intent mIntent;
    RatingBar bar1;
    RatingBar bar2;
    EditText tag1;
    EditText tag2;
    EditText tag3;
    EditText tag4;
    EditText description;
    int Time;
    LocalDateTime rightNow;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_time_recorder);
        mIntent = getIntent();
        dbh = new DatabaseHelper(this);
        db = dbh.getWritableDatabase();
        dbh.fill(db);
        rightNow = LocalDateTime.now();
        int Year = mIntent.getIntExtra("Year",rightNow.getYear());
        int Month = mIntent.getIntExtra("Month",rightNow.getMonthOfYear());
        int Day = mIntent.getIntExtra("Day",rightNow.getDayOfMonth());
        int Hour = mIntent.getIntExtra("Hour",rightNow.getHourOfDay());
        String query = "SELECT Productivity, Energy, Long, Lat, Tag1, Tag2, Tag3, Tag4, Description, Time FROM Log " +
                "WHERE Year = ? AND Month = ? AND Day = ? AND Hour = ?";
        String[] theArgs = {Integer.toString(Year), Integer.toString(Month), Integer.toString(Day), Integer.toString(Hour)};
        Cursor tmp = db.rawQuery(query, theArgs);
        tmp.moveToFirst();
        bar1 = (RatingBar) findViewById(R.id.ratingBar);
        bar2 = (RatingBar) findViewById(R.id.ratingBar2);
        tag1 = (EditText) findViewById(R.id.tag1);
        tag2 = (EditText) findViewById(R.id.tag2);
        tag3 = (EditText) findViewById(R.id.tag3);
        tag4 = (EditText) findViewById(R.id.tag4);
        bar1.setNumStars(tmp.getInt(0));
        bar2.setNumStars(tmp.getInt(1));
        String tmp2 = tmp.getString(4);
        if (tmp2 != null){
            tag1.setText(tmp2);
        }
        tmp2 = tmp.getString(5);
        if (tmp2 != null){
            tag2.setText(tmp2);
        }
        tmp2 = tmp.getString(6);
        if (tmp2 != null){
            tag3.setText(tmp2);
        }
        tmp2 = tmp.getString(7);
        if (tmp2 != null){
            tag4.setText(tmp2);
        }
        tmp2 = tmp.getString(8);
        if (tmp2 != null){
            description.setText(tmp2);
        }
        Time = tmp.getInt(9);
        tmp.close();
        Button submit = (Button) findViewById(R.id.submit);
        submit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                //String query2 = "UPDATE Log SET Productivity = " + Integer.toString(bar1.getNumStars()) + ", Energy = " +
                //        Integer.toString(bar2.getNumStars()) +" WHERE Time = " + Integer.toString(Time) +";";
                String query2 = "UPDATE Log SET Productivity = " + Integer.toString(bar1.getNumStars()) + " WHERE Time = " + Integer.toString(Time) +";";
                Log.i("TAG", query2);
                db.execSQL(query2);
                db.close();
                finish();

            }
        });




        db.close();
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_time_recorder, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

这是我收到的错误消息：

4560-4560/apps.abcd.jj.recordtimeeveryhour I/TAG﹕ UPDATE Log SET Productivity = 5 WHERE Time = 2523;
12-05 21:52:02.083    4560-4560/apps.abcd.jj.recordtimeeveryhour D/AndroidRuntime﹕ Shutting down VM
12-05 21:52:02.083    4560-4560/apps.abcd.jj.recordtimeeveryhour W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40abe228)
12-05 21:52:02.093    4560-4560/apps.abcd.jj.recordtimeeveryhour E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at android.database.sqlite.SQLiteStatement.releaseAndUnlock(SQLiteStatement.java:302)
            at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:99)
            at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:2031)
            at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1971)
            at apps.abcd.jj.recordtimeeveryhour.TimeRecorder$1.onClick(TimeRecorder.java:93)

第93行是：db.execSQL（query2）;

任何想法是怎么回事？ Logcat报告了正在执行的查询。尝试在我在Dropbox链接中附加的完全相同的数据库上执行该查询..它工作正常！那么为什么它在我的Android程序中不起作用呢？