Android登录页面制作并且记住账号密码

一、页面搭建

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    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">

    <EditText
        android:id="@+id/et_UserName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:ems="10"
        android:hint="请输入账号"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/et_Password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:ems="10"
        android:hint="请输入密码"
        android:inputType="textPassword"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/et_UserName" />

    <CheckBox
        android:id="@+id/checkBox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="记住密码"
        app:layout_constraintStart_toStartOf="@+id/et_Password"
        app:layout_constraintTop_toBottomOf="@+id/et_Password" />

    <Button
        android:id="@+id/button"
        android:onClick="Login"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="24dp"
        android:layout_marginLeft="24dp"
        android:layout_marginEnd="24dp"
        android:layout_marginRight="24dp"
        android:text="安全登录"
        app:layout_constraintBottom_toBottomOf="@+id/checkBox"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/checkBox"
        app:layout_constraintTop_toTopOf="@+id/checkBox" />


</android.support.constraint.ConstraintLayout>

二、代码实现

package com.hiscene.test;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

public class MainActivity extends AppCompatActivity {

    EditText et_userName;
    EditText et_password;
    CheckBox checkBox;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.login_layout);

        et_userName = findViewById(R.id.et_UserName);
        et_password = findViewById(R.id.et_Password);
        checkBox = findViewById(R.id.checkBox);

        LoadInfo();
    }

    private void LoadInfo()
    {
        File file=new File(MainActivity.this.getFilesDir(),"data.txt");
        if (!file.exists()) return;

        try {
            FileReader reader = new FileReader(file);
            BufferedReader br=new BufferedReader(reader);
            String text=br.readLine();
            String[] arr=text.split("#");
            et_userName.setText(arr[0]);
            et_password.setText(arr[1]);
            checkBox.setChecked(true);
            br.close();

        }catch (Exception e) {
            e.printStackTrace();
        }

    }

    public void Login(View view) {

        String userName=et_userName.getText().toString().trim();
        String password= et_password.getText().toString().trim();

        if (TextUtils.isEmpty(userName)|| TextUtils.isEmpty(password))
        {
            Toast.makeText(MainActivity.this, "用户名或密码不能为空！", Toast.LENGTH_SHORT).show();
            return;
        }

        if (checkBox.isChecked())
        {
            File file=new File(MainActivity.this.getFilesDir(),"data.txt");
            try {

                OutputStream out=new FileOutputStream(file);
                OutputStreamWriter osw=new OutputStreamWriter(out,"UTF-8");
                BufferedWriter writer=new BufferedWriter(osw);
                writer.write(userName+"#"+password);
                writer.flush();
                writer.close();

            } catch (Exception e) {
                e.printStackTrace();
            }

        }

    }
}