直接显示网络图片的工具

package com.example.dell.myapplication;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.widget.ImageView;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * Created by dell on 2017/8/3.
 */

public class MyImageView extends ImageView {
    //子线程不能操作UI，通过Handler设置图片
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            Bitmap bitmap = (Bitmap) msg.obj;
            setImageBitmap(bitmap);
        }
    };

    public MyImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public MyImageView(Context context) {
        super(context);
    }

    public MyImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setImageURL(final String path){
        //开启一个线程用于联网
        new Thread(){
            @Override
            public void run() {
                try {
                    //把传过来的路径转成URL
                    URL url = new URL(path);
                    //获取连接
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    //使用GET方法访问网络
                    connection.setRequestMethod("GET");
                    //超时时间为10秒
                    connection.setConnectTimeout(10000);
                    //获取返回码
                    int code = connection.getResponseCode();
                    if (code == 200){
                        InputStream inputStream = connection.getInputStream();
                        //使用工厂把网络的输入流生产Bitmap
                        Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                        //利用Message把图片发给Handler
                        Message msg = Message.obtain();
                        msg.obj = bitmap;
                        handler.sendMessage(msg);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

}

<Button
        android:text="Button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/button" />

    <com.example.dell.myapplication.MyImageView
        android:id="@+id/image_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

final MyImageView myImageView = (MyImageView) findViewById(R.id.image_view);
        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myImageView.setImageURL("https://pic.cnblogs.com/avatar/1142647/20170416093225.png");
            }
        });

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