将图像从 HTML 显示到 TextView - Android

Question

我正在使用 AsuncTask 从 Web 服务获取 JSON。从 JSON 我得到“标题”和“全文”。 “title”是简单文本，而“fulltext”是 HTML 文本。在这个 HTML 中，我有一些带有图像的文本和 URL。我想在 TextView 中显示整个 HTML。

我的代码：

    TextView tvArticleTitle = (TextView) findViewById(R.id.tvArticleTitle);
    TextView tvArticleText = (TextView) findViewById(R.id.tvArticleText);

public class GetArticleTask extends AsyncTask<String, Void, Boolean> {

        private String title;
        private String text;
        private ProgressDialog dialog;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            dialog = new ProgressDialog(context);
            dialog.setMessage("Please wait!");
            dialog.setCancelable(false);
            dialog.show();
        }

        @Override
        protected Boolean doInBackground(String... params) {

            try {
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(Variables.URL_ARTICLE);
                httpPost.setEntity(new UrlEncodedFormEntity(pair));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                String data = EntityUtils.toString(httpEntity);

                int status = httpResponse.getStatusLine().getStatusCode();

                if (status == HttpStatus.SC_OK) {

                    JSONObject jRealObject = new JSONObject(data);

                    title = jRealObject.getString("title").toString();
                    text = jRealObject.getString("fulltext").toString();

                    return true;
                }
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return false;
        }

        @Override
        protected void onPostExecute(Boolean result) {
            super.onPostExecute(result);

            if (result == false) {
                Toast.makeText(context, Variables.ERROR_MESSAGE, Toast.LENGTH_SHORT).show();
            } else {

                tvArticleTitle.setText(title);
                tvArticleText.setText(Html.fromHtml(text, new ImageGetter() {

                    @Override
                    public Drawable getDrawable(String source) {

                        Drawable drawable = null;
                        URL sourceURL;

                        try {
                            sourceURL = new URL(source);
                            URLConnection urlConnection = sourceURL.openConnection();
                            urlConnection.connect();
                            InputStream inputStream = urlConnection.getInputStream();
                            BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream);
                            Bitmap bm = BitmapFactory.decodeStream(bufferedInputStream);

                            // convert Bitmap to Drawable
                            drawable = new BitmapDrawable(getResources(), bm);

                            drawable.setBounds(0, 0, bm.getWidth(), bm.getHeight());
                        } catch (MalformedURLException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }

                        return drawable;
                    }

                }, null));

                if(dialog.isShowing()) {
                    dialog.dismiss();
                }
            }
        }
    }
}

它给了我错误：android.os.NetworkOnMainThreadException。我知道我需要再次在 AsyncTask 上进行此操作，但我不知道如何拆分代码。

Answer 1

如果你的 json 有点像这样：

{ 
  "text": "some text",
  "html1": "Hi, check out my fb profile picture at <img src = 'http:\/\/abc.com/image1.png'\/> ",
  "html2": "Hi, check out my whatsapp profile picture at <img src = 'http:\/\/abc.com\/image1.png'\/> ",
   .
   .
   .
}

然后 ：

public class MainActivity extends Activity implements ImageGetter {
    private final static String TAG = "MainActivity";
    private TextView mTv;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String source = <your source from json here>;

        Spanned spanned = Html.fromHtml(source, this, null);
        mTv = (TextView) findViewById(R.id.text);
        mTv.setText(spanned);
    }

    @Override
    public Drawable getDrawable(String source) {
        LevelListDrawable d = new LevelListDrawable();
        Drawable empty = getResources().getDrawable(R.drawable.ic_launcher);
        d.addLevel(0, 0, empty);
        d.setBounds(0, 0, empty.getIntrinsicWidth(), empty.getIntrinsicHeight());

        new LoadImage().execute(source, d);

        return d;
    }

    class LoadImage extends AsyncTask<Object, Void, Bitmap> {

        private LevelListDrawable mDrawable;

        @Override
        protected Bitmap doInBackground(Object... params) {
            String source = (String) params[0];
            mDrawable = (LevelListDrawable) params[1];
            Log.d(TAG, "doInBackground " + source);
            try {
                InputStream is = new URL(source).openStream();
                return BitmapFactory.decodeStream(is);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            Log.d(TAG, "onPostExecute drawable " + mDrawable);
            Log.d(TAG, "onPostExecute bitmap " + bitmap);
            if (bitmap != null) {
                BitmapDrawable d = new BitmapDrawable(bitmap);
                mDrawable.addLevel(1, 1, d);
                mDrawable.setBounds(0, 0, bitmap.getWidth(), bitmap.getHeight());
                mDrawable.setLevel(1);
                // i don't know yet a better way to refresh TextView
                // mTv.invalidate() doesn't work as expected
                CharSequence t = mTv.getText();
                mTv.setText(t);
            }
        }
    }
}