Android font ttf or otf font displaying random characters / letters

Question

I have a custom Viewone in which I draw some text. I use various free otf / ttf font files that are available in the resources folder

public class ProjectView extends View {
    private final Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

    private void init(Context context) {
        textPaint.setStyle(Paint.Style.FILL);
        textPaint.setAntiAlias(true);

        typeface = Typeface.createFromAsset(context.getAssets(), "fonts" + File.separator + fontFileName);
        textPaint.setTypeface(typeface);
    }
}

Everything seems to work just fine, except for one thing: the words I draw are randomly mixed up, which means that the letters are accidentally replaced with other letters or characters.

Here is an example:

The correct word is in the left image, but sometimes it is drawn as in the correct image. The call invalidate()again, everything returns correctly, fixes the problem.

ListView, - , notifyDatasetChanged() . :

@Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View view = convertView;
        ViewHolder holder;
        if (convertView == null) {
            view = inflater.inflate(R.layout.list_item_fonts, null);

            holder = new ViewHolder();
            holder.txtFont = (TextView) view.findViewById(R.id.txtFont);
            view.setTag(holder);
        } else {
            holder = (ViewHolder) view.getTag();
        }

        //tried this two but no success
        holder.txtFont.setPaintFlags(holder.txtFont.getPaintFlags() | Paint.SUBPIXEL_TEXT_FLAG | Paint.DEV_KERN_TEXT_FLAG);
        holder.txtFont.getPaint().setSubpixelText(true);

        holder.txtFont.setTextSize(TypedValue.COMPLEX_UNIT_SP, fonts.get(position).getSize());

        holder.txtFont.setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts" + File.separator + font.getFileName()));
}

, , . !

Answer 1

, getView. .

.

Application, .

Answer 2

, -. . lru.

import android.content.Context;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.text.TextPaint;
import android.text.style.MetricAffectingSpan;
import android.util.LruCache;

public class TypefaceSpan extends MetricAffectingSpan {
    private static LruCache<String, Typeface> sTypefaceCache = new LruCache<>(12);
    private Typeface mTypeface;

    public TypefaceSpan(Context context, String typefaceName) {
        mTypeface = sTypefaceCache.get(typefaceName);

        if (mTypeface == null) {
            mTypeface = Typeface.createFromAsset(context.getApplicationContext().getAssets(),
                    String.format("fonts/%s", typefaceName));
            sTypefaceCache.put(typefaceName, mTypeface);
        }
    }

    @Override
    public void updateMeasureState(TextPaint p) {
        p.setTypeface(mTypeface);
        p.setFlags(p.getFlags() | Paint.SUBPIXEL_TEXT_FLAG);
    }

    @Override
    public void updateDrawState(TextPaint tp) {
        tp.setTypeface(mTypeface);
        tp.setFlags(tp.getFlags() | Paint.SUBPIXEL_TEXT_FLAG);
    }
}

:

private TypefaceSpan typefaceSpan;

:

typefaceSpan = new TypefaceSpan(context, "name_of_font.otf");

GetView:

typefaceSpan.updateDrawState(holder.title.getPaint());