StaticLayout too much time taking

问题:

I use StaticLayout to Paginate my Html Text. But when I use large text in StaticLayout Constructing process is very heavy and taking a lot of time. It's Just Happen in androids below android 5 How can I resolve this problem? this is my code

public class PageSplitter {
    private final int pageWidth;
    private final int pageHeight;
    private final float lineSpacingMultiplier;
    private final float lineSpacingExtra;
    private final List<CharSequence> pages = new ArrayList<CharSequence>();
    private SpannableStringBuilder mSpannableStringBuilder;

    public PageSplitter(int pageWidth, int pageHeight, float lineSpacingMultiplier, float lineSpacingExtra) {
        this.pageWidth = pageWidth;
        this.pageHeight = pageHeight;
        this.lineSpacingMultiplier = lineSpacingMultiplier;
        this.lineSpacingExtra = lineSpacingExtra;

    }

    public void append(CharSequence charSequence) {
        this.mSpannableStringBuilder.append(charSequence);
    }

    public void split(TextPaint textPaint) {
        StaticLayout staticLayout = new StaticLayout(
                mSpannableStringBuilder,
                textPaint,
                pageWidth,
                Layout.Alignment.ALIGN_NORMAL,
                lineSpacingMultiplier,
                lineSpacingExtra,
                false
        );
        int startLine = 0;
        while(startLine < staticLayout.getLineCount()) {
            int startLineTop = staticLayout.getLineTop(startLine);
            int endLine = staticLayout.getLineForVertical(startLineTop + pageHeight);
            int endLineBottom = staticLayout.getLineBottom(endLine);
            int lastFullyVisibleLine;
            if(endLineBottom > startLineTop + pageHeight)
                lastFullyVisibleLine = endLine - 1;
            else
                lastFullyVisibleLine = endLine;
            int startOffset = staticLayout.getLineStart(startLine);
            int endOffset = staticLayout.getLineEnd(lastFullyVisibleLine);
            pages.add(mSpannableStringBuilder.subSequence(startOffset, endOffset));
            startLine = lastFullyVisibleLine + 1;
        }
    }

    public List<CharSequence> getPages() {
        return pages;
    }
}

And I used it here

private void initialViewPager(float textSize, float lineSpace){
        TextPaint textPaint = new TextPaint();
        float textSizeInPx = UnitConverter.spToPixels(this, textSize);
        textPaint.setTextSize(textSizeInPx);
        ru.appheads.pagesplitterapp.garbage.PageSplitter splitter = new ru.appheads.pagesplitterapp.garbage.PageSplitter(pageWidth,pageHeight,1,0);

        for (String bookTopicText : bookTopicTexts) {
            splitter.append( bookTopicText);
        }
        splitter.split(textPaint);

        TextPagerAdapter textPagerAdapter = new TextPagerAdapter(getSupportFragmentManager(), splitter.getPages(), textSize, lineSpace,  pageHeight);
        pageSeekbar.setMax(textPagerAdapter.getCount()-1);
        pagesView.setAdapter(textPagerAdapter);
    }

I debug my code and I know this part of code is my problem :

StaticLayout staticLayout = new StaticLayout(
                mSpannableStringBuilder,
                textPaint,
                pageWidth,
                Layout.Alignment.ALIGN_NORMAL,
                lineSpacingMultiplier,
                lineSpacingExtra,
                false
        );