Android(安卓)SqlLite的简单实用

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();            }        });    }}

1.先写一个MySqlHelper类,用于创建数据库

2.写个Dialog的页面布局zhuce_item.xml

3.LoginActivity页面的代码：

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