Android基于Sqlite怎么实现注册和登录功能

本篇内容主要讲解"Android基于Sqlite怎么实现注册和登录功能"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"Android基于Sqlite怎么实现注册和登录功能"吧!

实现逻辑

项目的图片结构图如下

代码

user class

public class User {    private String name;    //用户名    private String password;     //密码    public User(String name, String password) {        this.name = name;        this.password = password;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

DBOpenHelper class

import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import java.util.ArrayList;public class DBOpenHelper extends SQLiteOpenHelper {    private SQLiteDatabase db;    public DBOpenHelper(Context context){//打开数据库        super(context,"db_test",null,1);//1：上下文，2：数据库名，3：允许我们查询数据时返回一个Cursor，4：当前数据库的版本号        db = getReadableDatabase();    }    @Override    public void onCreate(SQLiteDatabase db){//建表（user）语句        db.execSQL("CREATE TABLE IF NOT EXISTS user(" +//PRIMARY key 将id设为主键 ，AUTOINCREMENT 设置id列自为增长                "_id INTEGER PRIMARY KEY AUTOINCREMENT," +                "name TEXT," +                       //text 文本类型                "password TEXT)");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){//重写升级        db.execSQL("DROP TABLE IF EXISTS user");        onCreate(db);    }    public void add(String name,String password){//重写添加        db.execSQL("INSERT INTO user (name,password) VALUES(?,?)",new Object[]{name,password});    }    public void delete(String name,String password){//重写删除        db.execSQL("DELETE FROM user WHERE name = AND password ="+name+password);    }    public void updata(String password){//重写更新        db.execSQL("UPDATE user SET password = ?",new Object[]{password});    }    public ArrayList getAllData(){//将表内信息返回成一个list        ArrayList list = new ArrayList();        Cursor cursor = db.query("user",null,null,null,null,null,"name DESC");//1表名，2列，3行，4行，5指定列进行过滤，6进一步过滤。7得到的信息进行排序（desc逆序）        while(cursor.moveToNext()){//一行一行遍历            String name = cursor.getString(cursor.getColumnIndex("name"));//移动到name列，读取出来            String password = cursor.getString(cursor.getColumnIndex("password"));            list.add(new User(name,password));//添加到user 的list中        }        return list;//把list返回    }}

activity_login.xml

LoginActivity

import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.content.Intent;import android.text.TextUtils;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;import java.util.ArrayList;public class LoginActivity extends AppCompatActivity implements View.OnClickListener {    private DBOpenHelper mDBOpenHelper;    private EditText mEtLoginactivityUsername;    private EditText mEtLoginactivityPassword;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_login);        initView();        mDBOpenHelper = new DBOpenHelper(this);    }    private void initView() {        // 初始化控件        mEtLoginactivityUsername = findViewById(R.id.et_loginactivity_username);        mEtLoginactivityPassword = findViewById(R.id.et_loginactivity_password);        // 设置点击事件监听器    }    public void onClick(View view) {        switch (view.getId()) {            // 跳转到注册界面            case R.id.tv_loginactivity_register:                startActivity(new Intent(this, RegisterActivity.class));                finish();                break;            case R.id.bt_loginactivity_login:                String name = mEtLoginactivityUsername.getText().toString().trim();//.trim（）删除两边的空格                String password = mEtLoginactivityPassword.getText().toString().trim();                if (!TextUtils.isEmpty(name) && !TextUtils.isEmpty(password)) {//TextUtils.isEmpty（）输入框是空值或者你就敲了几下空格键该方法都会返回true                    ArrayList data = mDBOpenHelper.getAllData();//data为获取的user表内的user信息                    boolean match = false;                    for (int i = 0; i < data.size(); i++) {//遍历比较                        User user = data.get(i);//获取data里的第i个user信息                        if (name.equals(user.getName()) && password.equals(user.getPassword())) {//将信息与输入的信息进行对比                            match = true;                            break;                        } else {                            match = false;                        }                    }                    if (match) {                        Toast.makeText(this, "登录成功", Toast.LENGTH_SHORT).show();                        Intent intent = new Intent(this, MainActivity.class);                        startActivity(intent);                        finish();//销毁此Activity                    } else {                        Toast.makeText(this, "用户名或密码不正确，请重新输入", Toast.LENGTH_SHORT).show();                    }                } else {                    Toast.makeText(this, "请输入你的用户名或密码", Toast.LENGTH_SHORT).show();                }                break;        }    }}

activity_register.xml

RegisterActivity

import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.RelativeLayout;import android.widget.Toast;import androidx.appcompat.app.AppCompatActivity;public class RegisterActivity extends AppCompatActivity implements View.OnClickListener {    private DBOpenHelper mDBOpenHelper;    private Button mBtRegisteractivityRegister;    private ImageView mIvRegisteractivityBack;    private EditText mEtRegisteractivityUsername;    private EditText mEtRegisteractivityPassword;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_register);        initView();        mDBOpenHelper = new DBOpenHelper(this);    }    private void initView(){        mEtRegisteractivityUsername = findViewById(R.id.et_registeractivity_username);        mEtRegisteractivityPassword = findViewById(R.id.et_registeractivity_password);}    public void onClick(View view) {        switch (view.getId()) {            case R.id.iv_registeractivity_back: //返回登录页面                Intent intent1 = new Intent(this, LoginActivity.class);                startActivity(intent1);                finish();                break;            case R.id.bt_registeractivity_register:    //注册按钮                //获取用户输入的用户名、密码、验证码                String username = mEtRegisteractivityUsername.getText().toString().trim();                String password = mEtRegisteractivityPassword.getText().toString().trim();                //注册验证                if (!TextUtils.isEmpty(username) && !TextUtils.isEmpty(password)) {                    mDBOpenHelper.add(username, password);//将用户名和密码加入到数据库的表内中                    Intent intent2 = new Intent(this, LoginActivity.class);                    startActivity(intent2);                    finish();                    Toast.makeText(this, "验证通过，注册成功", Toast.LENGTH_SHORT).show();                } else {                    Toast.makeText(this, "未完善信息，注册失败", Toast.LENGTH_SHORT).show();                }                break;        }    }}

实现效果

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