package com.aimee.android.play.qqlogin;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.CheckBox;

import android.widget.EditText;

import android.widget.Toast;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.InputStreamReader;

import static android.text.TextUtils.isEmpty;

public class MainActivity extends AppCompatActivity {

    private EditText mEtnumber;

    private EditText mEtPasswd;

    private CheckBox mCbRemember;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        mEtnumber = findViewById(R.id.et_qq);

        mEtPasswd = findViewById(R.id.et_password);

        mCbRemember = findViewById(R.id.cb_remember);

        //1.找到界面上的控件

        //2.点击按钮，将用户输入的用户名和密码保存到文件当中

        //3.如果说下次启动app，那么就从文件当中读取出来显示到编辑框

        restoreInfo();

    }

    /**

     * 根据原来保存的文件信息，把QQ号码和密码信息显示到界面

     * */

    private void restoreInfo() {

        File file = new File(this.getFilesDir(), "info.txt");

        //如果文件存在并且有内容就读取出来

        if (file.exists() && file.length() > 0){

            try {

                FileInputStream fis = new FileInputStream(file);

                BufferedReader br = new BufferedReader(new InputStreamReader(fis));

                String info = br.readLine();

                String qq = info.split("##")[0];

                String pwd = info.split("##")[1];

                mEtnumber.setText(qq);

                mEtPasswd.setText(pwd);

            } catch (Exception e) {

                e.printStackTrace();

            }

        }

    }

    /**

     * 登录按钮的点击事件

     *

     * @param view

     * */

    public void login(View view) {

        String qq = mEtnumber.getText().toString().trim();

        String password = mEtPasswd.getText().toString().trim();

        if (isEmpty(qq) || isEmpty(password)){

            Toast.makeText(this,"用户名和密码不能为空",Toast.LENGTH_SHORT).show();

            return;

        }else {

            //判断是否需要记录用户名和密码

            if (mCbRemember.isChecked()){

//                Toast.makeText(this,this.getExternalFilesDir(null).getAbsolutePath(),Toast.LENGTH_SHORT).show();

                //被选中的状态，需要记录用户名和密码

                File file = new File(this.getFilesDir(),"info.txt");

                try {

                    FileOutputStream fos = new FileOutputStream(file);

                    String info = qq + "##" + password;

                    fos.write(info.getBytes());

                    fos.close();

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

            //模拟登录，当前输入的用户名和密码联网操作对比云端数据库是否匹配

            if ("10000".equals(qq) && "123456".equals(password)){

                Toast.makeText(this,"登录成功",Toast.LENGTH_SHORT).show();

            }

            else {

                Toast.makeText(this,"登录失败",Toast.LENGTH_SHORT).show();

            }

        }

    }

}

<?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"

    tools:context=".MainActivity">

    <ImageView

        android:id="@+id/imageView"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginStart="8dp"

        android:layout_marginTop="108dp"

        android:layout_marginEnd="8dp"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toTopOf="parent"

        app:srcCompat="@mipmap/qq" />

    <EditText

        android:id="@+id/et_qq"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginStart="8dp"

        android:layout_marginTop="32dp"

        android:layout_marginEnd="8dp"

        android:ems="10"

        android:hint="请输入QQ号码"

        android:gravity="center"

        android:inputType="textPersonName"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/imageView" />

    <EditText

        android:id="@+id/et_password"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginStart="8dp"

        android:layout_marginTop="30dp"

        android:layout_marginEnd="8dp"

        android:ems="10"

        android:hint="请输入密码"

        android:gravity="center"

        android:inputType="textPassword"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/et_qq" />

    <Button

        android:id="@+id/button"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginStart="8dp"

        android:layout_marginTop="88dp"

        android:layout_marginEnd="8dp"

        android:onClick="login"

        android:text="登录"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/et_password" />

    <CheckBox

        android:id="@+id/cb_remember"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginStart="8dp"

        android:layout_marginTop="16dp"

        android:layout_marginEnd="8dp"

        android:text="记住密码"

        app:layout_constraintEnd_toEndOf="parent"

        app:layout_constraintStart_toStartOf="parent"

        app:layout_constraintTop_toBottomOf="@+id/et_password" />

</android.support.constraint.ConstraintLayout>