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修改mainactivity.java- package com.example.xinwei.databasetest;
- import android.support.v7.app.AlertDialog;
- import android.support.v7.app.AppCompatActivity;
- import android.os.Bundle;
- import android.view.View;
- import android.widget.Button;
- public class MainActivity extends AppCompatActivity {
- private MyDatabaseHelper dbHelper;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- dbHelper = new MyDatabaseHelper(this,"BookStore.db",null,2);
- Button createDatabase = (Button)findViewById(R.id.create_database);
- createDatabase.setOnClickListener(new View.OnClickListener() {
- @Override
- public void onClick(View view) {
- dbHelper.getWritableDatabase();
- }
- });
- }
- }
复制代码
修改mydatabasehelper.java- package com.example.xinwei.databasetest;
- import android.content.Context;
- import android.database.sqlite.SQLiteDatabase;
- import android.database.sqlite.SQLiteOpenHelper;
- import android.widget.Toast;
- /**
- * Created by xinwei on 2017/10/16.
- */
- public class MyDatabaseHelper extends SQLiteOpenHelper {
- public static final String CREATE_BOOK = "create table book("
- +"id integer primary key autoincrement,"
- +"author text,"
- +"price real,"
- +"pages integer,"
- +"name text)";
- public static final String CREATE_CATEGORY = "create table Category("
- +"id integer primary key autoincrement,"
- +"category_name text,"
- +"category_code integer)";
- private Context mContext;
- public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
- super(context, name, factory, version);
- mContext=context;
- }
- @Override
- public void onCreate(SQLiteDatabase sqLiteDatabase) {
- sqLiteDatabase.execSQL(CREATE_BOOK);
- sqLiteDatabase.execSQL(CREATE_CATEGORY);
- Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
- }
- @Override
- public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
- sqLiteDatabase.execSQL("drop table if exists book");
- sqLiteDatabase.execSQL("drop table if exists Category");
- onCreate(sqLiteDatabase);
- }
- }
复制代码
这样就成功对数据库进行了更新 |
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