android - 在 Android 上使用 TextView 和 Html.ImageGetter 异步显示图像？

Question

我想用 SpannableString 设置一个 TextView，它来自下面的方法:

Html.fromHtml(String source, Html.ImageGetter imageGetter, 
   Html.TagHandler tagHandler)

但是这里的ImageGetter需要重写下面的方法:

public abstract Drawable getDrawable(String source)

因为我需要从互联网上获取 drawable，所以我必须异步执行它，但似乎不是。

如何让它发挥作用？谢谢。

Answer 1

这些人做得很好，这是我使用 Square 的 Picasso 库的解决方案:

//...
final TextView textView = (TextView) findViewById(R.id.description);
        Spanned spanned = Html.fromHtml(getIntent().getStringExtra(EXTRA_DESCRIPTION),
                new Html.ImageGetter() {
                    @Override
                    public Drawable getDrawable(String source) {
                        LevelListDrawable d = new LevelListDrawable();
                        Drawable empty = getResources().getDrawable(R.drawable.abc_btn_check_material);;
                        d.addLevel(0, 0, empty);
                        d.setBounds(0, 0, empty.getIntrinsicWidth(), empty.getIntrinsicHeight());
                        new ImageGetterAsyncTask(DetailActivity.this, source, d).execute(textView);

                        return d;
                    }
                }, null);
        textView.setText(spanned);
//...


class ImageGetterAsyncTask extends AsyncTask<TextView, Void, Bitmap> {


    private LevelListDrawable levelListDrawable;
    private Context context;
    private String source;
    private TextView t;

    public ImageGetterAsyncTask(Context context, String source, LevelListDrawable levelListDrawable) {
        this.context = context;
        this.source = source;
        this.levelListDrawable = levelListDrawable;
    }

    @Override
    protected Bitmap doInBackground(TextView... params) {
        t = params[0];
        try {
            Log.d(LOG_CAT, "Downloading the image from: " + source);
            return Picasso.with(context).load(source).get();
        } catch (Exception e) {
            return null;
        }
    }

    @Override
    protected void onPostExecute(final Bitmap bitmap) {
        try {
            Drawable d = new BitmapDrawable(context.getResources(), bitmap);
            Point size = new Point();
            ((Activity) context).getWindowManager().getDefaultDisplay().getSize(size);
            // Lets calculate the ratio according to the screen width in px
            int multiplier = size.x / bitmap.getWidth();
            Log.d(LOG_CAT, "multiplier: " + multiplier);
            levelListDrawable.addLevel(1, 1, d);
            // Set bounds width  and height according to the bitmap resized size
            levelListDrawable.setBounds(0, 0, bitmap.getWidth() * multiplier, bitmap.getHeight() * multiplier);
            levelListDrawable.setLevel(1);
            t.setText(t.getText()); // invalidate() doesn't work correctly...
        } catch (Exception e) { /* Like a null bitmap, etc. */ }
    }
}

我的 2 美分...和平!