安卓开发之图片查看器

package com.lidaochen.test;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;

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


public class MainActivity extends AppCompatActivity {
    private EditText et_path;
    private ImageView iv_pic;

    // 创建handler对象
    public Handler handler = new Handler()
    {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            Bitmap bitmap = (Bitmap)msg.obj;
            // 设置图片到ImageView
            iv_pic.setImageBitmap(bitmap);
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 找到  ImageView 和 EditText控件
        et_path = (EditText)findViewById(R.id.et_path);
        iv_pic = (ImageView)findViewById(R.id.iv_pic);
    }
    public void click(View v)
    {
        new Thread()
        {
            public void run()
            {
                try
                {
                    // 获取图片路径
                    String path = et_path.getText().toString().trim();
                    // 创建url对象
                    URL url = new URL(path);
                    //  获取HttpURLConnection对象
                    HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                    // 设置请求方式
                    httpURLConnection.setRequestMethod("GET");
                    // 设置超时时间
                    httpURLConnection.setReadTimeout(5000);
                    // 获取服务器返回的状态码
                    int code = httpURLConnection.getResponseCode();
                    if (code == 200)
                    {
                        // 获取图片数据，不管什么数据，都是以流的形式返回
                        InputStream in = httpURLConnection.getInputStream();
                        // 通过位图工厂，获取位图
                        final Bitmap bitmap = BitmapFactory.decodeStream(in);
                        // 创建MSG 对象
                        Message msg = new Message();
                        msg.obj = bitmap;
                        handler.sendMessage(msg);
                    }
                }
                catch (Exception e)
                {
                    e.printStackTrace();
                }
            }
        }.start();
    }
}