Android 异步加载图片

1.运行后界面图：

2.主要代码

　　2.1 activity_main.xml 布局

 1 <LinearLayout

 2         android:layout_width="match_parent"

 3         android:layout_height="50dp"

 4         android:orientation="horizontal" >

 5 

 6         <EditText

 7             android:id="@+id/etUrl"

 8             android:layout_width="166dp"

 9             android:layout_height="wrap_content"

10             android:layout_weight="0.65"

11             android:text="http://img3.redocn.com/20100206/20100206_c3f11163684180e389c57LUEUjSMDaax.jpg"

12             android:ems="10" />

13 

14         <Button

15             android:id="@+id/btnLoad"

16             android:layout_width="wrap_content"

17             android:layout_height="wrap_content"

18             android:onClick="ShowImg"

19             android:text="加载" />

20     </LinearLayout>

21 

22     <ImageView

23         android:id="@+id/ivImg"

24         android:layout_width="match_parent"

25         android:layout_height="match_parent"

26         android:src="@drawable/ic_launcher" />

XML布局

　　2.2 MainActivity.java

 1     private Handler handler=new Handler(){  

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

 3             switch (msg.what) {  

 4             case 1:  

 5                 Bitmap bitmap=(Bitmap) msg.obj;  

 6                 ivImg.setImageBitmap(bitmap);  

 7                 break;  

 8             default:  

 9                 break;  

10             }  

11         }  

12     };  

13     //showImg

14     public void ShowImg(View view){

15         final String path = etUrl.getText().toString();

16         if(!TextUtils.isEmpty(path)){

17             new Thread(){

18                 public void run(){

19                     try{

20                         URL url = new URL(path);

21                         HttpURLConnection httpUrlConn = (HttpURLConnection)url.openConnection();

22                         httpUrlConn.setRequestMethod("GET");

23                         //超时

24                         httpUrlConn.setConnectTimeout(5000);

25                         int responseCode = httpUrlConn.getResponseCode();

26                         if(responseCode == 200){

27                             InputStream is = httpUrlConn.getInputStream();

28                             Bitmap bitmap = BitmapFactory.decodeStream(is);

29 

30                             Message msg = new Message();

31                             msg.what=1;

32                             msg.obj = bitmap;

33                             handler.sendMessage(msg);

34                         }

35 

36                     }catch(MalformedURLException e){

37                         e.printStackTrace();

38                     }catch(IOException e){

39                         e.printStackTrace();

40                     }

41                 }

42             }.start();

43         }else{

44             Toast.makeText(this, "图片路径不能为空", Toast.LENGTH_LONG).show();

45         }

46         

47     }

48     

View Code

　　2.3 同样 在XML布局中找到Button注册一个onclick事件  引用MainActivity中的ShowImg方法

3. AndroidManifest.xml 中注册联网权限

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

4. demo

https://github.com/cnfanhua/A-AsynLoadPic