改变值，可显示zai在

在theves下面的两个value都要增加名字代码

       <item name="windowActionBar">false</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowFullscreen">true</item>

设置背景图片 在avtivity里面添加background

<androidx.constraintlayout.widget.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"
    android:background="@drawable/splash"
    tools:context=".SplashActivity">

并且在AndroidMainifest里面用iintent

建立一个新的activity,添加背景图，定时器

添加控件，并且设置名字，hint隐藏密码

inputtype输入密码类型

判断用户名和密码

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.QuickContactBadge;
import android.widget.Toast;

public class LoginActivity extends AppCompatActivity {

    private EditText dtName,dtPasswd;
    private Button btnLogin,btnPasswd;

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

    private void initView(){
        dtName=findViewById(R.id.dtLoginName);
        dtPasswd=findViewById(R.id.dtLoginPasswd);
        btnLogin=findViewById(R.id.btnLogin);
        btnPasswd=findViewById(R.id.btnPasswd);

        btnPasswd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String sName=dtName.getText().toString();
                String sPasswd=dtPasswd.getText().toString();
                if((!sName.equals("admin"))||(!sPasswd.equals("123456"))){
                    Toast.makeText(LoginActivity.this,"用户名或者密码错错误",Toast.LENGTH_SHORT).show();
                    return;
                }
                Toast.makeText(LoginActivity.this,"登陆成功",Toast.LENGTH_SHORT).show();
            }
        });
    }

}

跳转到主窗口 startactivity

btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String sName=dtName.getText().toString();
                String sPasswd=dtPasswd.getText().toString();
                if((!sName.equals("admin"))||(!sPasswd.equals("123456"))){
                    Toast.makeText(LoginActivity.this,"用户名或者密码错错误",Toast.LENGTH_SHORT).show();
                    return;
                }
                Toast.makeText(LoginActivity.this,"登陆成功",Toast.LENGTH_SHORT).show();
        
                Intent intent=new Intent(LoginActivity.this,MainActivity.class);
                startActivity(intent);
            }
        });

启动web服务器

要打开文件，bin目录下，一直挂着

创建线程

 private void checkWebServe(){
        String sUrl="http://10.107.24.12:8080/newsIndex.json";

        Thread t=new Thread(new Runnable() {
            @Override
            public void run() {
               try {
                   URL url=new URL(sUrl);
                   HttpURLConnection urlConn=(HttpURLConnection) url.openConnection();
                    urlConn.setRequestMethod("GET");
                   InputStream ins=urlConn.getInputStream();
                   if(null==ins){
                       
                       
                   }else {
                       byte[] date=new byte[1000];
                       int ret=ins.read(date,0, date.length);
                       String s=new String(date,0,ret);
                       Log.d("test",s);
                       ins.close();
                   }
                   
               }
               catch (Exception e){
                   e.printStackTrace();
               }
            }
        });
    }

需调用

    <uses-permission android:name="android.permission.INTERNET"/>

明文传输

  android:usesCleartextTraffic="true"

调用checkWebServe

等待一秒

     t.start();
        try {
            t.join(1000);

        }
        catch (Exception e){
            
        }