app的简单创建：

新建虚拟手机:

效果：

res->layout->activity_main.xml:

点击code：

<?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=".MainActivity">


    <LinearLayout
        android:layout_height="200dp"
        android:layout_width="match_parent"
        android:layout_marginTop="150dp"
        android:background="#dddddd"
        android:orientation="vertical">


        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:text="用户登录"
            android:textAlignment="center"
            android:textSize="20dp" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:paddingLeft="50dp"
            android:paddingRight="50dp">

            <TextView
                android:layout_width="60dp"
                android:layout_height="match_parent"
                android:gravity="center"
                android:text="用户名" />

            <EditText
                android:id="@+id/txt_user"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:inputType="text"
                android:singleLine="true"
                android:textSize="14dp" />


        </LinearLayout>


        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:paddingLeft="50dp"
            android:paddingRight="50dp">

            <TextView
                android:layout_width="60dp"
                android:layout_height="match_parent"
                android:gravity="center"
                android:text="密码" />

            <EditText
                android:id="@+id/txt_pwd"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:inputType="textPassword"
                android:singleLine="true"
                android:textSize="14dp" />


        </LinearLayout>


        <LinearLayout
            android:gravity="center"
            android:layout_width="match_parent"
            android:layout_height="50dp">

            <Button
                android:id="@+id/btn_login"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginRight="10dp"
                android:text="登录"/>

            <Button
                android:id="@+id/btn_reset"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="10dp"
                android:text="重置"/>

        </LinearLayout>

    </LinearLayout>

</LinearLayout>

Logcat:

package com.example.demo;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    public   Button btnLogin;
    public Button btnReset;
    public TextView txtUser, txtPwd;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

       initView();
       //绑定事件
        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.e("事件", "点击登录");
            }
        });

        btnReset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.e("事件", "点击登录");
            }
        });


    }
    public void initView(){
        btnLogin = findViewById(R.id.btn_login);
        btnReset = findViewById(R.id.btn_reset);

        txtUser = findViewById(R.id.txt_user);
        txtPwd = findViewById(R.id.txt_pwd);
    }
}

简单功能：

重置：

 public void doReset(){
        //清空输入框
        txtUser.setText("");
        txtPwd.setText("");
    }

登录功能：

引入模块:

implementation ("com.squareup.okhttp3:okhttp:4.9.1")

这里：

记得要下载：

给权限：

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

这里我搞了一个flask项目，不能用127.0.0.1

from flask import Flask, request

app = Flask(__name__)


@app.route("/login", methods=['GET', 'POST'])
def login():
    print(request.form)
    user = request.form.get('user')
    pwd = request.form.get('pwd')
    return "OOOK"


if __name__ == '__main__':
    app.run(host="0.0.0.0", port=8000)

    

https://blog.csdn.net/lw_zhaoritian/article/details/121291067

报错：

not permitted by network security policy

https://blog.csdn.net/qq_33401954/article/details/102617018

效果：