TextView显示HTML文本时<IMG>标签指定图片的显示处理

TextView显示文本时是支持一些HTML标签的（具体支持那些标签会在下面附录列出），不会需要先用HTML的static方法fromHtml来转换一下。

Spanned text = Html.fromHtml(htmlString);
textView.setText(text);

这样，TextView就会把支持的一些HTML标签以HTML的形式显示出来。不过，如果htmlString中含有<img>标签，并需要在TextView中正确显示的话就必须做进一步的处理了。

Spanned text = Html.fromHtml(htmlString, imageGetter, null);
textView.setText(text);

通过Html的另一个重载的fromHtml方法，指定ImageGetter，来获取网络图片，异步加载的方式来显示图片。

下面给出ImageGetter的一个实现类，大部分代码来自网络，只针对关键部分做了完善，先看代码，后面详细说明。

 1 public class URLImageGetter implements ImageGetter {
 2     Context context;
 3     TextView textView;
 4 
 5     public URLImageGetter(Context context, TextView textView) {
 6         this.context = context;
 7         this.textView = textView;
 8     }
 9     
10     @Override
11     public Drawable getDrawable(String paramString) {
12         final URLDrawable urlDrawable = new URLDrawable(context);
13         
14         ImageGetterAsyncTask getterTask = new ImageGetterAsyncTask(urlDrawable);
15         getterTask.execute(paramString);
16         return urlDrawable;
17     }
18     
19     public class ImageGetterAsyncTask extends AsyncTask<String, Void, Drawable> {
20         URLDrawable urlDrawable;
21         
22         public ImageGetterAsyncTask(URLDrawable drawable) {
23             this.urlDrawable = drawable;
24         }
25         
26         @Override
27         protected void onPostExecute(Drawable result) {
28             if (result != null) {
29                 urlDrawable.drawable = result;
30                 
31                 URLImageGetter.this.textView.requestLayout();
32             }
33         }
34         
35         @Override
36         protected Drawable doInBackground(String... params) {
37             String source = params[0];
38             return fetchDrawable(source);
39         }
40         
41         public Drawable fetchDrawable(String url) {
42             try {
43                 InputStream is = fetch(url);
44                 
45                 Rect bounds = SystemInfoUtils.getDefaultImageBounds(context);
46                 Bitmap bitmapOrg = BitmapFactory.decodeStream(is);
47                 Bitmap bitmap = Bitmap.createScaledBitmap(bitmapOrg, bounds.right, bounds.bottom, true);
48                 
49                 BitmapDrawable drawable = new BitmapDrawable(bitmap);
50                 drawable.setBounds(bounds);
51                 
52                 return drawable;
53             } catch (ClientProtocolException e) {
54                 e.printStackTrace();
55             } catch (IOException e) {
56                 e.printStackTrace();
57             }
58             
59             return null;
60         }
61         
62         private InputStream fetch(String url) throws ClientProtocolException, IOException {
63             DefaultHttpClient client = new DefaultHttpClient();
64             HttpGet request = new HttpGet(url);
65             
66             HttpResponse response = client.execute(request);
67             return response.getEntity().getContent();
68         }
69     }
70     
71 }

URLImageGetter

1 public class URLDrawable extends BitmapDrawable { 2 protected Drawable drawable; 3 4 public URLDrawable(Context context) { 5 this.setBounds(SystemInfoUtils.getDefaultImageBounds(context)); 6 7 drawable = context.getResources().getDrawable(R.drawable.default_image_min); 8 drawable.setBounds(SystemInfoUtils.getDefaultImageBounds(context)); 9 } 10 11 @Override 12 public void draw(Canvas canvas) { 13 Log.d("test", "this=" + this.getBounds()); 14 if (drawable != null) { 15 Log.d("test", "draw=" + drawable.getBounds()); 16 drawable.draw(canvas); 17 } 18 } 19 20 }

1 public static Rect getDefaultImageBounds(Context context) { 2 Display display = ((Activity)context).getWindowManager().getDefaultDisplay(); 3 int width = display.getWidth(); 4 int height = (int) (width * 9 / 16); 5 6 Rect bounds = new Rect(0, 0, width, height); 7 return bounds; 8 }

TextView显示HTML文本时标签指定图片的显示处理

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