Android 实现记住账号密码

清疚 2022-01-23 11:35 335阅读 0赞

首先创建一个界面

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout 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=".LoginActivity"
        android:orientation="vertical">
        <EditText
            android:id="@+id/loginEdt"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入用户名"/>
        <EditText
            android:id="@+id/passwordEdt"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入密码"/>
        <Button
            android:id="@+id/loginBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="登录"/>
        <CheckBox
            android:id="@+id/saveChb"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="save"/>
    
    </LinearLayout>

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先附上源代码

package com.example.administrator.ch05_2;
    
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.CheckBox;
    import android.widget.EditText;
    import android.widget.Toast;
    
    public class LoginActivity extends AppCompatActivity implements View.OnClickListener{
    
        private Button loginBtn;
        private EditText loginEdt;
        private EditText passwordEdt;
        private CheckBox saveChb;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_login);
    
            loginEdt = findViewById(R.id.loginEdt);
            passwordEdt = findViewById(R.id.passwordEdt);
            loginBtn = findViewById(R.id.loginBtn);
            saveChb = findViewById(R.id.saveChb);
            loginBtn.setOnClickListener(this);
            SharedPreferences sp2=getSharedPreferences("Logindb",MODE_PRIVATE);
            if(sp2.getBoolean("save",false)==true  ){    //判断是否写入了数值save==true
                getDB();
            }
        }
    
        @Override
        public void onClick(View v) {
            switch (v.getId()){
                case R.id.loginBtn:
                    if(saveChb.isChecked()){                    //当多选按钮按下时执行报损数据
                        saveDB();
                    }
                    else {
                        clearDB();
                    }
                    if(loginEdt.getText().toString().trim().length()==0){
                        Toast.makeText(LoginActivity.this,"用户名密码不能为空",Toast.LENGTH_LONG).show();
                    }
                    else {
                        Intent intent=new Intent(LoginActivity.this,MainActivity.class);
                        startActivity(intent);
                    }
                    finish();
                    break;
            }
        }
        //清除
        private void clearDB(){
            SharedPreferences sp=getSharedPreferences("Logindb",MODE_PRIVATE);
            SharedPreferences.Editor editor=sp.edit();
            editor.clear();
            editor.commit();
        }
        //保存数据
        private void saveDB(){
            SharedPreferences sp=getSharedPreferences("Logindb",MODE_PRIVATE);
            SharedPreferences.Editor editor=sp.edit();
            editor.putString("loginEdt",loginEdt.getText().toString());
            editor.putString("passwordEdt",passwordEdt.getText().toString());
            editor.putBoolean("save",true);
            editor.commit();            //写入数据
            Toast.makeText(LoginActivity.this,"sd",Toast.LENGTH_LONG).show();
        }
        //读取数据
        private void getDB(){
            SharedPreferences sp=getSharedPreferences("Logindb",MODE_PRIVATE);
            String name= sp.getString("loginEdt","");
            String password=sp.getString("passwordEdt","");
            loginEdt.setText(name);
            passwordEdt.setText(password);
        }
    }

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1kxMTcyMjE1Nzg0_size_16_color_FFFFFF_t_70]: /images/20220123/96af319af7784e54ab7a769e48851a72.png