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DatabaseHelpepackage 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SQLiteActivitypackage 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