4 8.OC14-Category

当使用android:lineSpacingExtra="5dp" 后面背景就会变大

public class BetterHighlightSpan extends ReplacementSpan {

    private int backgroundColor;
    public BetterHighlightSpan(int backgroundColor) {
        super();
        this.backgroundColor = backgroundColor;
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, FontMetricsInt fm) {
        return Math.round(paint.measureText(text, start, end));
    }

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

        // save current color
        int oldColor = paint.getColor();

        // calculate new bottom position considering the fontSpacing
        float fontSpacing = paint.getFontSpacing();
        float newBottom = bottom - fontSpacing;

        // change color and draw background highlight
        RectF rect = new RectF(x, top, x + paint.measureText(text, start, end), newBottom);
        paint.setColor(backgroundColor);
        canvas.drawRect(rect, paint);

        // revert color and draw text
        paint.setColor(oldColor);
        canvas.drawText(text, start, end, x, y, paint);
    }

}

TextView textView = (TextView) findViewById(R.id.textView);
SpannableStringBuilder builder = new SpannableStringBuilder("here some text and more of it");
builder.setSpan(new BetterHighlightSpan(Color.CYAN), 4, 8, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(builder);