get请求方式获取网络图片

 

package com.example.testapplication;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.ImageView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

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

public class GetpngActivity extends AppCompatActivity {
    // 第二步 主线程接收到子线程发送过来的消息进行处理显示
    private ImageView main_iv_show;
    private Handler handler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(@NonNull Message message) {
            if(message.what == 0x001){
                Bitmap bm = (Bitmap) message.obj;
                // ??
                main_iv_show.setImageBitmap(bm);
            }
            return false;
        }
    });
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_getpng);
       main_iv_show = (ImageView) findViewById(R.id.main_image_show);

    }

    // button 点击事件
    public void getPic(View view){
        String path = "https://img2.mukewang.com/5adfee7f0001cbb906000338-240-135.jpg";
        // 创建一个线程对象
        GetPicThread gpt = new GetPicThread(path,handler);
        Thread t = new Thread(gpt);
        t.start();
    }

    // 第一步 子线程去请求获取网络图片
    // 获取网络的线程，耗时操作需要再子线程操作

    public class GetPicThread implements Runnable{
        private String path = null;
        // handler 用于将数据送到主线程中
        private Handler handler = null;

        public GetPicThread(String path, Handler handler) {
            this.path = path;
            this.handler = handler;
        }

        @Override
        public void run() {
            HttpURLConnection conn = null;
            InputStream is = null;
            InputStreamReader istr = null;
            BufferedReader br = null;
            try {
                // 1.定义艺哥URL对象
                URL url = new URL(path);
                // 2.通过url获取一个HttpURLConnerction();
                conn = (HttpURLConnection) url.openConnection();
                // 3.设置请求方式
                conn.setRequestMethod("GET");
                // 4.设置超时时间
                conn.setConnectTimeout(5000);
                conn.setReadTimeout(5000);
                if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){
                    // 获取到网络输入的字符流
                    is = conn.getInputStream();
                    // 借助位图工厂类的方法，将流转换为tu
                    Bitmap bm = BitmapFactory.decodeStream(is);
                    // 将获取的数据发送给主线程中去
                    Message message = handler.obtainMessage();
                    message.what = 0x0001;
                    message.obj = bm;
                    handler.sendMessage(message);
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:id="@+id/main_btn"
        android:onClick="getPic"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="获取网络图片"/>
    <ImageView
        android:id="@+id/main_image_show"
        android:layout_width="150dp"
        android:layout_height="150dp" />

</LinearLayout>