android富文本append网络图片的加载方案

先占位，加载完之后重绘view

val builder = SpannableStringBuilder()
val width = DpUtil.dp2px(35)
val height = DpUtil.dp2px(30)
val drawable = URLImageSpanParser(context, view).getDrawable(bean.url_img, width, height)
val imgSpan = CenterAlignImageSpan(drawable)
val spannableString = SpannableString("aaaa")
spannableString.setSpan(
    imgSpan,
    0,
    spannableString.length,
    Spanned.SPAN_EXCLUSIVE_EXCLUSIVE
)
builder.append(spannableString)
builder.append(" ")
textView.setText(builder)

用到的工具类

class URLImageSpanParser(val context : Context?, val tv: TextView?) {
    fun getDrawable(url:String?, width:Int, height:Int): Drawable {
        var urlDrawable = UikitURLDrawable()
        if(width == 0){

        }else{
            urlDrawable.setBounds(0, 0,width, height)
        }
        loadDrawableAsync(urlDrawable, url, width, height)
        return urlDrawable
    }

    private fun loadDrawableAsync(urlDrawable : UikitURLDrawable, url:String?, width: Int, height: Int){
        ImgLoader.displayDrawable(context, url, object : DrawableCallback {
            override fun onLoadSuccess(drawable: Drawable) {
                drawable.setBounds(0, 0, width, height)
                urlDrawable.drawable = drawable
                urlDrawable.invalidateSelf()
                tv?.postInvalidate()
            }

            override fun onLoadFailed() {

            }
        })
    }
}

class UikitURLDrawable:BitmapDrawable(){
    var drawable:Drawable? = null
    override fun draw(canvas: Canvas) {
        if(drawable != null){
            drawable?.draw(canvas)
        }
    }
}

public class CenterAlignImageSpan extends ImageSpan {

    public CenterAlignImageSpan(Drawable drawable) {
        super(drawable);

    }

    public CenterAlignImageSpan(Bitmap b) {
        super(b);
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom,
                     Paint paint) {

        Drawable b = getDrawable();
        Paint.FontMetricsInt fm = paint.getFontMetricsInt();
        int transY = (y + fm.descent + y + fm.ascent) / 2 - b.getBounds().bottom / 2;//计算y方向的位移
        canvas.save();
        canvas.translate(x, transY);//绘制图片位移一段距离
        b.draw(canvas);
        canvas.restore();
    }


}

public static void displayDrawable(Context context, String url, final DrawableCallback callback) {
    if (context == null || TextUtils.isEmpty(url)) {
        return;
    }
    try {
        Glide.with(context).asDrawable().load(new GlideUrl(url, sHeaders)).skipMemoryCache(SKIP_MEMORY_CACHE).into(new SimpleTarget<Drawable>() {
            @Override
            public void onResourceReady(@NonNull Drawable resource, @Nullable Transition<? super Drawable> transition) {
                if (callback != null) {
                    callback.onLoadSuccess(resource);
                }
            }

            @Override
            public void onLoadFailed(@Nullable Drawable errorDrawable) {
                if (callback != null) {
                    callback.onLoadFailed();
                }
            }

        });
    } catch (Exception e) {
        e.printStackTrace();
    }
}

参考文章：Android 使用ImageSpan加载网络图片-CSDN博客