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

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/activity_main"android:layout_width="match_parent"android:layout_height="match_parent"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"android:orientation="vertical"tools:context="com.example.administrator.eschool.MainActivity"><TextViewandroid:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center"android:textSize="25dp"android:text="ESchool 大学生校园交易平台" /><EditTextandroid:id="@+id/username"android:layout_width="match_parent"android:hint="请输入您的用户名"android:layout_height="wrap_content" /><EditTextandroid:layout_width="match_parent"android:layout_height="wrap_content"android:inputType="textPassword"android:hint="请输入您的密码"android:ems="10"android:id="@+id/password" /><!--点击button来获取百度主页源代码--><Buttonandroid:id="@+id/login"android:layout_width="wrap_content"android:layout_gravity="center"android:text="确认登录"android:layout_height="wrap_content" /><!--用来展示获取到的源码--><TextViewandroid:text="TextView"android:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/textView" /></LinearLayout>

package com.example.administrator.eschool;import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;

// 这几个要自己导入
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;public class MainActivity extends AppCompatActivity implements View.OnClickListener {private EditText username;private EditText password;private Button login;private HttpGet httpGet = null;HttpClient httpClient = null;private Handler mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);textView.setText(msg.obj.toString());}};private TextView textView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initView();}private void initView() {username = (EditText) findViewById(R.id.username);password = (EditText) findViewById(R.id.password);login = (Button) findViewById(R.id.login);login.setOnClickListener(this);textView = (TextView) findViewById(R.id.textView);textView.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.login:submit();break;}}private void submit() {// validateString usernameString = username.getText().toString().trim();if (TextUtils.isEmpty(usernameString)) {Toast.makeText(this, "请输入您的用户名", Toast.LENGTH_SHORT).show();return;}String passwordString = password.getText().toString().trim();if (TextUtils.isEmpty(passwordString)) {Toast.makeText(this, "请输入您的密码", Toast.LENGTH_SHORT).show();return;}// TODO validate success, do somethingnew Thread(new Runnable() {@Overridepublic void run() {// 生成一个请求对象httpGet = new HttpGet("https://www.baidu.com");// 生成一个http客户端对象httpClient = new DefaultHttpClient();// 用客户端发送请求对象try {HttpResponse httpResponse = httpClient.execute(httpGet);// 接收http返回的响应HttpEntity httpEntity = httpResponse.getEntity();// 获得http响应的内容InputStream inputStream = httpEntity.getContent();BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));String result = "";String line = "";while ((line = reader.readLine()) != null) {result += line;}Message msg = new Message();msg.obj = result;mHandler.sendMessage(msg);} catch (IOException e) {e.printStackTrace();}}}).start();}
}