Android入门之网络图片查看器

package com.xsx.image;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.net.URL;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.text.TextUtils;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.EditText;

import android.widget.ImageView;

import android.widget.Toast;

public class MainActivity extends Activity {

protected static final int CHANGE_UI = 1;

protected static final int ERROR = 2;

private EditText et_address;

private ImageView iv_show;

//1、在主线程建立消息处理器

private Handler handler = new Handler(){

public void
handleMessage(android.os.Message msg){

if(msg.what==CHANGE_UI){

Bitmap
bitmap = (Bitmap) msg.obj;

iv_show.setImageBitmap(bitmap);

}else
if(msg.what==ERROR){

Toast.makeText(MainActivity.this,
"显示图片失败", 0).show();

}

};

};

@Override

protected
void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

et_address = (EditText) findViewById(R.id.et_address);

iv_show = (ImageView) findViewById(R.id.iv_image);

}

public void
click(View view){

final String path =
et_address.getText().toString().trim();

if(TextUtils.isEmpty(path)){

Toast.makeText(this,
"图片地址不能为空", 0).show();

}else{

new Thread(){

public void
run(){

//链接服务器get请求获取图片

try{

URL url = new
URL(path);

//根据url发送http请求

HttpURLConnection
conn = (HttpURLConnection) url.openConnection();

conn.setRequestMethod("GET");//设置请求方式

conn.setConnectTimeout(5000);

//

conn.setReadTimeout(10000);

//

conn.setRequestProperty(field,
newValue);

//得到服务器返回的响应码

int code =
conn.getResponseCode();

if(code==200){

InputStream
is = conn.getInputStream();

Bitmap
bitmap = BitmapFactory.decodeStream(is);

//

iv_show.setImageBitmap(bitmap);

Message
msg = new Message();

msg.what
= CHANGE_UI;

msg.obj
= bitmap;

handler.sendMessage(msg);

}else{

Message
msg = new Message();

msg.what
= ERROR;

handler.sendMessage(msg);

}

}catch (Exception e){

e.printStackTrace();

Message msg =
new Message();

msg.what
= ERROR;

handler.sendMessage(msg);

}

}

}.start();

}

}

}