麻烦帮我找一下错，我真的无能无力了，谢谢。

Question

 这是Java文件，类名是DatabaseHelpe

package com.example.database;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.view.Menu;

public class DatabaseHelper extends SQLiteOpenHelper{
private static final int VERSION=1;
public  DatabaseHelper(Context context,String name,CursorFactory factory,int version){
 super(context,name,factory,version);
 
}
public  DatabaseHelper(Context context,String name){
 this(context,name,VERSION);
 
}
public  DatabaseHelper(Context context,String name,int version){
 this(context,name,null,version);
 
}
   public void onCreate(SQLiteDatabase db) {
   System.out.println("create a Database");
   db.execSQL("create table user(id int,name varchar(20))");
    }

   public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion) {
    System.out.println("update a Database");
     }
}

这是另一个Java文件，类名是SQLiteActivity

package com.example.database;

import android.app.Activity;
import android.content.ContentValues;
import android.content.DialogInterface.OnClickListener;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class SQLiteActivity extends Activity{
private Button  button1;
private Button  button2;
private Button  button3;
private Button  button4;
private Button  button5;
protected void onCreate(Bundle saveInstanceState){
 super.onCreate(saveInstanceState);
 setContentView(R.layout.main);
 button1=(Button) findViewById(R.id.button1);
 button2=(Button) findViewById(R.id.button2);
 button3=(Button) findViewById(R.id.button3);
 button4=(Button) findViewById(R.id.button4);
 button5=(Button) findViewById(R.id.button5);
 button1.setOnClickListener(new CreatdbOnClickListener());
 button2.setOnClickListener(new UpdatedbOnClickListener());
 button3.setOnClickListener(new InsertOnClickListener());
 button4.setOnClickListener(new UpdatedbOnClickListener());
 button5.setOnClickListener(new QuerryOnClickListener());
}
class CreatdbOnClickListener implements OnClickListener{
 public void onClick(View v){
  DatabaseHelper dbHelper=new DatabaseHelper(SQLiteActivity.this,"test.db");
  SQLiteDatabase db=dbHelper.getReadableDatabase();
 }
 
}
class UpdateOnClickListener implements OnClickListener{
 public void onClick(View v){
  DatabaseHelper dbHelper=new DatabaseHelper(SQLiteActivity.this,"test.db",2);
  SQLiteDatabase db=dbHelper.getReadableDatabase();
 }
}
class InsertOnClickListener implements OnClickListener{
 public void onClick(View v){
  ContentValues cv=new ContentValues();
  cv.put("id", 1);
  cv.put("name", "hyl");
  DatabaseHelper dbHelper=new DatabaseHelper(SQLiteActivity.this,"test.db",2);
  SQLiteDatabase db=dbHelper.getReadableDatabase();
  db.insert("user",null,cv);
 }
 
}
class UpdatOnClickListener implements OnClickListener{
 public void onClick(View v){
  DatabaseHelper dbHelper=new DatabaseHelper(SQLiteActivity.this,"test.db",2);
  SQLiteDatabase db=dbHelper.getWritableDatabase();
  ContentValues values=new ContentValues();
  values.put("name","heyulu");
  db.update("user",values,"id=?",new String[] {"1"});
  System.out.println("----------------update------------");
 }
 }
class QuerryOnClickListener implements OnClickListener{
 public void onClick(View v){
  DatabaseHelper dbHelper=new DatabaseHelper(SQLiteActivity.this,"test.db",2);
  SQLiteDatabase db=dbHelper.getWritableDatabase();
  Cursor cursor=db.query("user",new String[]{"id","name"},"id=?",new String[]{"1"},null,null,null);
  while(cursor.moveToNext()){
   String name=cursor.getString(cursor.getColumnIndex("name"));
   System.out.println("query--->"+name);
  }
 }
}

}
还有一个xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
     android:layout_height="match_parent"
      android:orientation="vertical">
<Button
     android:id="@+id/button1"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/creatdb"
    />
<Button
     android:id="@+id/button2"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/updatedb"
    />
<Button
     android:id="@+id/button3"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/ins"
    />
<Button
     android:id="@+id/button4"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/upd"
    />
<Button
     android:id="@+id/button5"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/que"
    />
</LinearLayout>

Answer 1

错误log也贴上来啊