Android中基于Sqlite实现注册和登录功能

前言

写这篇博客主要是为了巩固一下学的Sqlite知识以及梳理一下这个项目的逻辑

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<User> getAllData(){//将表内信息返回成一个list

        ArrayList<User> list = new ArrayList<User>();
        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

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#eeeeee"
    tools:context=".LoginActivity">

    <RelativeLayout
        android:id="@+id/rl_loginactivity_top"
        android:layout_width="match_parent"
        android:layout_height="70dp"
  >

        <ImageView
            android:id="@+id/iv_loginactivity_back"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignParentTop="true"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="20dp"

            android:clickable="true" />

        <TextView
            android:id="@+id/tv_loginactivity_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="登录"
            android:textColor="#3A5FCD"
            android:textSize="20dp"
            android:layout_toRightOf="@+id/iv_loginactivity_back"
            android:layout_centerVertical="true"
            android:layout_alignParentLeft="true"
            android:layout_marginLeft="30dp"
            />
        <TextView
            android:id="@+id/tv_loginactivity_register"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="注册"
            android:textColor="#3A5FCD"
            android:textSize="20dp"

            android:layout_centerVertical="true"
            android:layout_alignParentRight="true"
            android:layout_marginRight="30dp"
            android:clickable="true"
            android:onClick="onClick"
            />
    </RelativeLayout>

    <LinearLayout
        android:id="@+id/ll_loginactivity_two"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_below="@+id/rl_loginactivity_top"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        >
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/tv_loginactivity_username"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="用户名："/>
            <EditText
                android:id="@+id/et_loginactivity_username"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="手机号/邮箱/用户名"/>
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/tv_loginactivity_password"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="密    码："/>
            <EditText
                android:id="@+id/et_loginactivity_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="登录密码"
                android:inputType="textPassword"/>
        </LinearLayout>
    </LinearLayout>
    <Button
        android:id="@+id/bt_loginactivity_login"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/ll_loginactivity_two"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:text="登录"
        android:textColor="#3A5FCD"
        android:gravity="center"
        android:onClick="onClick"
        />

</RelativeLayout>

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<User> 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

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#eeeeee"
    tools:context=".RegisterActivity">

    <RelativeLayout
        android:id="@+id/rl_registeractivity_top"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        >
        <ImageView
            android:id="@+id/iv_registeractivity_back"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_centerVertical="true"
            android:layout_marginLeft="10dp"
            android:clickable="true"
            />

        <TextView
            android:id="@+id/tv_registeractivity_register"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="注册"
            android:textColor="#3A5FCD"
            android:textSize="20dp"

            android:layout_centerVertical="true"
            android:layout_marginLeft="20dp"
            />
    </RelativeLayout>

    <LinearLayout
        android:id="@+id/ll_registeractivity_body"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_below="@+id/rl_registeractivity_top"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        >
        <!-- 第一个文本编辑框  输入用户名 -->
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/tv_registeractivity_username"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="用户名："/>
            <EditText
                android:id="@+id/et_registeractivity_username"
                android:layout_width="match_parent"
                android:layout_height="50dp"
                android:hint="请输入用户名"
                android:gravity="center_vertical"
                android:layout_marginLeft="10dp"
                />
        </LinearLayout>
        <!-- 第二个文本编辑框  输入密码 -->
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/tv_registeractivity_password1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="密    码："/>
            <EditText
                android:id="@+id/et_registeractivity_password"
                android:layout_width="match_parent"
                android:layout_height="50dp"
                android:gravity="center_vertical"
                android:layout_marginLeft="10dp"
                android:inputType="textPassword"
                android:hint="请输入密码" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginRight="15dp"
            android:layout_marginTop="10dp"
            android:orientation="horizontal" />
        <!-- 注册按钮 -->
        <Button
            android:id="@+id/bt_registeractivity_register"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:layout_marginLeft="5dp"
            android:textColor="#3A5FCD"
            android:text="注册"
            android:layout_marginTop="40dp"
            android:onClick="onClick"
            />

    </LinearLayout>
</RelativeLayout>

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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