Android SqlLite的简单实用
16lz
2021-01-23
1.先写一个MySqlHelper类,用于创建数据库
public class MySqlHelper extends SQLiteOpenHelper{ public MySqlHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { super(context, name, factory, version); } @Override public void onCreate(SQLiteDatabase db) { String sql = "create table if not exists user(_id Integer primary key autoincrement ,uname varchar(20),upass varchar(20))"; db.execSQL(sql); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }}2.写个Dialog的页面布局zhuce_item.xml
<?xml version="1.0" encoding="utf-8"?> 3.LoginActivity页面的代码：
public class LoginActivity extends AppCompatActivity { private EditText editName; private EditText editPass; private Button login; private Button zhuce; private Button update; private MySqlHelper helper; private SQLiteDatabase read; private SQLiteDatabase write; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); initView(); initData(); } /*获取控件，创建数据库对象*/ private void initView() { editName = (EditText) findViewById(R.id.name); editPass = (EditText) findViewById(R.id.pass); login = (Button) findViewById(R.id.login); zhuce = (Button) findViewById(R.id.zhuce); update = (Button) findViewById(R.id.update); //数据库helper对象 helper = new MySqlHelper(LoginActivity.this, "user", null, 2); //读取数据库数据的对象 read = helper.getReadableDatabase(); //写入数据库数据的对象 write = helper.getWritableDatabase(); } private void initData() { //登陆点击事件 login.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(LoginActivity.this,"登录",Toast.LENGTH_SHORT).show(); String name = editName.getText().toString(); String pass = editPass.getText().toString(); //查询语句 String sql = "select * from user where uname=? and upass=?"; Cursor query = read.rawQuery(sql,new String[]{name,pass}); if(query.moveToNext()==true){ Toast.makeText(LoginActivity.this,"登陆成功",Toast.LENGTH_SHORT).show(); }else{ Toast.makeText(LoginActivity.this,"账号或密码错误，请注册",Toast.LENGTH_SHORT).show(); } } }); zhuce.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(LoginActivity.this,"注册",Toast.LENGTH_SHORT).show(); AlertDialog.Builder dialog = new AlertDialog.Builder(LoginActivity.this); final View view1 = LayoutInflater.from(LoginActivity.this).inflate(R.layout.zhuce_item,null); dialog.setView(view1); dialog.setTitle("注册页面") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { EditText newname = (EditText) view1.findViewById(R.id.zhucename); EditText newpass = (EditText) view1.findViewById(R.id.zhucepass); String name = newname.getText().toString(); String pass = newpass.getText().toString(); //添加语句 String sql = "insert into user(uname,upass) values(?,?)"; write.execSQL(sql,new String[]{name,pass}); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { } }) .show(); } }); update.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Toast.makeText(LoginActivity.this,"忘记密码",Toast.LENGTH_SHORT).show(); AlertDialog.Builder dialog = new AlertDialog.Builder(LoginActivity.this); //引入Dialog的布局 final View view1 = LayoutInflater.from(LoginActivity.this).inflate(R.layout.zhuce_item,null); dialog.setView(view1); dialog.setTitle("修改密码") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { EditText newname = (EditText) view1.findViewById(R.id.zhucename); EditText newpass = (EditText) view1.findViewById(R.id.zhucepass); String name = newname.getText().toString(); String pass = newpass.getText().toString(); //修改语句 String sql1 = "update user set uname=?,upass=?where uname=?"; write.execSQL(sql1,new String[]{name,pass,name}); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { } }) .show(); } }); }}更多相关文章
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