如何使RelativeSizeSpan与顶部对齐 [英] How to make RelativeSizeSpan align to top

问题描述

我有以下字符串 RM123.456 .我想

• 使 RM 相对较小
• 使 RM 对齐到顶部

• Make RM relatively smaller
• Make RM aligned to top exactly

我几乎可以通过使用它来实现

I almost able to achieve it by using

spannableString.setSpan(new RelativeSizeSpan(0.50f), 0, index, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString, TextView.BufferType.SPANNABLE);

结果看起来像

但是，它与底部对齐.它不与顶部对齐.

However, it is aligned to the bottom. It doesn't align to the top.

我尝试使用SuperscriptSpan.看起来像

它不能满足我的要求

• SuperscriptSpan不会使文本变小.我无法控制其大小.
• SuperscriptSpan将使文本在顶部对齐"

• SuperscriptSpan doesn't make the text smaller. I'm not able to control its sizing.
• SuperscriptSpan will make the text "over the top align"

我可以知道，如何使RelativeSizeSpan与恰好对齐?

May I know, how can I make RelativeSizeSpan align to top exactly?

这是我希望实现的目标.

This is what I wish to achieve.

请注意，我们不希望使用2个TextViews解决方案.

推荐答案

但是我是以这种方式做到的:

However I did in this way:

activity_main.xml :

<TextView
    android:id="@+id/txtView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="50dp"
    android:textSize="26sp" />

MainActivity.java :

TextView txtView = (TextView) findViewById(R.id.txtView);

SpannableString spannableString = new SpannableString("RM123.456");
spannableString.setSpan( new TopAlignSuperscriptSpan( (float)0.35 ), 0, 2, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE );
txtView.setText(spannableString);

TopAlignSuperscriptSpan.java :

private class TopAlignSuperscriptSpan extends SuperscriptSpan {
        //divide superscript by this number
        protected int fontScale = 2;

        //shift value, 0 to 1.0
        protected float shiftPercentage = 0;

        //doesn't shift
        TopAlignSuperscriptSpan() {}

        //sets the shift percentage
        TopAlignSuperscriptSpan( float shiftPercentage ) {
            if( shiftPercentage > 0.0 && shiftPercentage < 1.0 )
                this.shiftPercentage = shiftPercentage;
        }

        @Override
        public void updateDrawState( TextPaint tp ) {
            //original ascent
            float ascent = tp.ascent();

            //scale down the font
            tp.setTextSize( tp.getTextSize() / fontScale );

            //get the new font ascent
            float newAscent = tp.getFontMetrics().ascent;

            //move baseline to top of old font, then move down size of new font
            //adjust for errors with shift percentage
            tp.baselineShift += ( ascent - ascent * shiftPercentage )
                    - (newAscent - newAscent * shiftPercentage );
        }

        @Override
        public void updateMeasureState( TextPaint tp ) {
            updateDrawState( tp );
        }
    }

希望这会对您有所帮助.

Hope this will help you.

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