获取网络请求

package com.example.lvxinxin.androidzxdayone;

import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * 今天的内容很重要
 * 1：JSON解析
 * 2：Handler Looper MessageQueue Message
 * 

 * HTTPURLConnection+URL（获取网址里面的数据）
 * 1：有网络就得加权限  android.permission.INTERNET
 * 2：我们自己分析代码应该怎么写？
 * 1：有效网址  http://api.expoon.com/AppNews/getNewsList/type/1/p/1
 * 2：
 */
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private String mUrl = "http://api.expoon.com/AppNews/getNewsList/type/1/p/1";
    private String mImageUrl = "https://img-my.csdn.net/uploads/201407/26/1406383265_8550.jpg";
    private String mPostUrl = "http://tcc.taobao.com/cc/json/mobile_tel_segment.htm";
    private Button mSendBtn,mSendImage,mPostBtn;
    private TextView mGetText;
    private ImageView mImage;
    @SuppressLint("HandlerLeak")
    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            int what = msg.what;
            switch (what) {
                case 1:
                    String string = msg.obj.toString();
                    mGetText.setText(string);
                    break;
                case 2:
                    Bitmap bt = (Bitmap) msg.obj;
                    mImage.setImageBitmap(bt);
                    break;
                case 3:
                    String string1 = msg.obj.toString();
                    mGetText.setText(string1);
                    break;
            }
        }
    };

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

    //初始化组件
    private void initViews() {
        mSendBtn = findViewById(R.id.Send_Btn);
        mSendBtn.setOnClickListener(this);
        mGetText = findViewById(R.id.Get_Text);
        mSendImage = findViewById(R.id.Send_Image_Btn);
        mSendImage.setOnClickListener(this);
        mImage = findViewById(R.id.Get_Image);
        mPostBtn = findViewById(R.id.Send_Post_Btn);
        mPostBtn.setOnClickListener(this);
    }

    private void getNetData() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    //定位一个网址服务
                    URL url = new URL(mUrl);
                    //由一个有效的网址服务返回这个对象
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    //设置请求方式
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5000);
                    InputStream stream = connection.getInputStream();
                    String inputStr = getInputStr(stream);
                    Message msg = new Message();
                    //这个what是标记的意思  Handler对象只能有一个  Message是有多个的
                    msg.what = 1;
                    msg.obj = inputStr;
                    mHandler.sendMessage(msg);
                    Log.e("网络字符串", inputStr);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();

    }

    //把流转成字符串
    private String getInputStr(InputStream stream) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(stream));
        StringBuffer sb = new StringBuffer();
        String str = null;
        while ((str = br.readLine()) != null) {
            sb.append(str);
        }
        return sb.toString();
    }


    private void getImageData(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    URL url = new URL(mImageUrl);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    if (connection.getResponseCode() ==200){
                        InputStream stream = connection.getInputStream();
                        Bitmap bitmap = BitmapFactory.decodeStream(stream);
                        Message msg = new Message();
                        msg.what = 2;
                        msg.obj = bitmap;
                        mHandler.sendMessage(msg);
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.Send_Btn:
                getNetData();
                break;
            case R.id.Send_Image_Btn:
                getImageData();
                break;
            case R.id.Send_Post_Btn:
                getPostData();
                break;
        }
    }
    //Post请求方式
    private void getPostData(){
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    URL url = new URL(mPostUrl);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("POST");
                    //开启可以想外输出的权限
                    connection.setDoOutput(true);
                    OutputStream outputStream = connection.getOutputStream();
                    String canshu = "tel=15850781443";
                    //把字符串转换成字节
                    outputStream.write(canshu.getBytes());
                    if (connection.getResponseCode() ==200){
                        InputStream stream = connection.getInputStream();
                        String inputStr = getInputStr(stream);
                        Message msg = new Message();
                        //这个what是标记的意思  Handler对象只能有一个  Message是有多个的
                        msg.what = 3;
                        msg.obj = inputStr;
                        mHandler.sendMessage(msg);
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

}