Android制作登录页面并且记住账号密码功能的实现代码

<?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>

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(\"data/data/com.hiscene.test/usre.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(\"data/data/com.hiscene.test/usre.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();
      }
    }
  }
}