网络图片查看器

MainActivity.java

package com.itheima.pictureviewer; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import android.support.v7.app.ActionBarActivity; import android.text.TextUtils; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.EditText; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends ActionBarActivity { protected static final int CHANGE_UI = 1; protected static final int Error = 2; private EditText et_path; private ImageView iv; //1.主线程创建消息处理器 private Handler handler = new Handler(){ public void handleMessage(android.os.Message msg){ if(msg.what == CHANGE_UI){ Bitmap bitmap =(Bitmap)msg.obj; iv.setImageBitmap(bitmap); }else if(msg.what == Error){ Toast.makeText(MainActivity.this, "显示图片失败", 0).show(); } }; }; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); et_path = (EditText)findViewById(R.id.et_path); iv = (ImageView)findViewById(R.id.iv); } public void click(View view){ final String path = et_path.getText().toString().trim(); if(TextUtils.isEmpty(path)){ Toast.makeText(this, "图片路径不能为空", 0).show(); }else{ new Thread(){ public void run() { //连接服务器get 请求获取图片 try { URL url = new URL(path); //根据url发送http的请求 HttpURLConnection conn = (HttpURLConnection)url.openConnection(); //设置请求方式 conn.setRequestMethod("GET"); conn.setConnectTimeout(5000);//5秒钟 conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; MyIE2; .NET CLR 1.1.4322) "); //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.setImageBitmap(bitmap); //告诉主线程一个消息 帮我更改一下界面 内容：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) { // TODO Auto-generated catch block e.printStackTrace(); Message msg = new Message(); msg.what = Error; handler.sendMessage(msg); } }; }.start(); } }}

res/layout/activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="com.itheima.pictureviewer.MainActivity" > <ImageView android:id="@+id/iv" android:layout_weight="1000" android:layout_width="match_parent" android:layout_height="match_parent" /> <EditText android:singleLine="true" android:text="http://e.hiphotos.baidu.com/album/w=230/sign=5405f4414d086e066aa8384832097b5a/f7246b600c3387440764470c500fd9f9d72aa019.jpg" android:id="@+id/et_path" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入图片路径" /> <Button android:onClick="click" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="浏览" /> </LinearLayout>