在滚动期间使用画布滞后

Question

我正在尝试在android中的文本上创建大纲/笔划。由于没有“简单的方法”来创建笔画，我尝试用画布实现它。我尝试了这个Textview扩展类（OutlineTextView.java）：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface; 
import android.text.Layout;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.widget.TextView;


public class OutlineTextView extends TextView {
    public OutlineTextView(Context context) {
            super(context);
            initPaint();
    }

    public OutlineTextView(Context context, AttributeSet attrs) {
            super(context, attrs);
            initPaint();
    }

    public OutlineTextView(Context context, AttributeSet attrs, int defStyle) {
            super(context, attrs, defStyle);
            initPaint();
    }

    private void initPaint() {
            mTextPaint = new TextPaint();
            mTextPaint.setAntiAlias(true);
            mTextPaint.setTextSize(getTextSize());
            mTextPaint.setColor(mColor);
            mTextPaint.setStyle(Paint.Style.FILL);
            mTextPaint.setTypeface(getTypeface());

            mTextPaintOutline = new TextPaint();
            mTextPaintOutline.setAntiAlias(true);
            mTextPaintOutline.setTextSize(getTextSize());
            mTextPaintOutline.setColor(mBorderColor);
            mTextPaintOutline.setStyle(Paint.Style.STROKE);
            mTextPaintOutline.setTypeface(getTypeface());
            mTextPaintOutline.setStrokeWidth(mBorderSize);
    }

    public void setText(String text) {
            super.setText(text);
            mText = text.toString();
            requestLayout();
            invalidate();
    }

    public void setTextSize(float size) {
            super.setTextSize(size);
            requestLayout();
            invalidate();
            initPaint();
    }

    public void setTextColor(int color) {
            super.setTextColor(color);
            mColor = color;
            invalidate();
            initPaint();
    }

    public void setShadowLayer(float radius, float dx, float dy, int color) {
            super.setShadowLayer(radius, dx, dy, color);
            mBorderSize = radius;
            mBorderColor = color;
            requestLayout();
            invalidate();
            initPaint();
    }

    public void setTypeface(Typeface tf, int style) {
            super.setTypeface(tf, style);
            requestLayout();
            invalidate();
            initPaint();
    }

    public void setTypeface(Typeface tf) {
            super.setTypeface(tf);
            requestLayout();
            invalidate();
            initPaint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
            Layout layout = new StaticLayout(getText(), mTextPaintOutline, getWidth(), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
            layout.draw(canvas);
            layout = new StaticLayout(getText(), mTextPaint, getWidth(), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
            layout.draw(canvas);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            Layout layout = new StaticLayout(getText(), mTextPaintOutline, measureWidth(widthMeasureSpec), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
            int ex = (int) (mBorderSize * 2 + 1);
            setMeasuredDimension(measureWidth(widthMeasureSpec) + ex, measureHeight(heightMeasureSpec) * layout.getLineCount() + ex);
    }

    private int measureWidth(int measureSpec) {
            int result = 0;
            int specMode = MeasureSpec.getMode(measureSpec);
            int specSize = MeasureSpec.getSize(measureSpec);

            if (specMode == MeasureSpec.EXACTLY) {
                    result = specSize;
            } else {
                    result = (int) mTextPaintOutline.measureText(mText) + getPaddingLeft() + getPaddingRight();
                    if (specMode == MeasureSpec.AT_MOST) {
                            result = Math.min(result, specSize);
                    }
            }

            return result;
    }

    private int measureHeight(int measureSpec) {
            int result = 0;
            int specMode = MeasureSpec.getMode(measureSpec);
            int specSize = MeasureSpec.getSize(measureSpec);

            mAscent = (int) mTextPaintOutline.ascent();
            if (specMode == MeasureSpec.EXACTLY) {
                    result = specSize;
            } else {
                    result = (int) (-mAscent + mTextPaintOutline.descent()) + getPaddingTop() + getPaddingBottom();
                    if (specMode == MeasureSpec.AT_MOST) {
                            result = Math.min(result, specSize);
                    }
            }
            return result;
    }

    private TextPaint mTextPaint;
    private TextPaint mTextPaintOutline;
    private String mText = "";
    private int mAscent = 0;
    private float mBorderSize;
    private int mBorderColor;
    private int mColor;
    private float mSpacingMult = 1.0f;
    private float mSpacingAdd = 0;
    private boolean mIncludePad = true;
 }

我在主要活动中使用此课程如下：

    OutlineTextView t2b = new OutlineTextView(this);
t2b.setGravity(Gravity.CENTER | Gravity.CENTER_HORIZONTAL);
t2b.setTextSize(44); 
t2b.setTextColor(Color.parseColor(Color.Green));
t2b.setShadowLayer(10, 1, 1, Color.BLACK);
Typeface type2 = Typeface.createFromAsset(getAssets(),"fonts/HelveticaLTStd-Bold.otf"); 


t2b.setTypeface(type2);
t2b.setText(percentage + "%");

    fl.addView(t2b);

fl是一个FrameLayout。现在输出是一个描边文本，它看起来就像我想要的那样。我的视图是一长串的图块，每个图块都是一个描边文本。文字不是我的问题。问题是滚动时的性能。如果我向下或向上滚动，性能会变慢并且不稳定。我认为问题是我绘制描边线的方式。我尝试了很多笔划文本的变化，并尝试了每个建议的笔画线变化。每次我都有同样的问题。如果我绘制没有笔划线的文本（但仍使用OutlineTextView），它会再次滚动，没有滞后，没有性能下降。只是绘制笔划线似乎会减慢系统速度。

P.S：这个OutlineTextView.java不是我自己的，我只是从互联网上得到它，因为这似乎画了一个描边文字。

如果有人能帮助我，我将感激不尽。