Aligning ImageSpan to the top of the TextView

问题

Currently, I wish to add an image in between texts and align it to the top of the TextView.

Something like this:

The only vertical alignments I can find are baseline (which seems to put it right down the center of the text) and align bottom.

What happens if I use ALIGN_BASELINE is:

Is there a way to align it to the top instead?

My current code:

    txtView.setText(this.addImageAsterisk(
        "The string to have asterisk at the end*"), BufferType.SPANNABLE);

then

private CharSequence addImageAsterisk(String string) {
    Drawable d = context.getResources().getDrawable(R.drawable.img_asterisk); 

    ImageSpan imageSpan = new ImageSpan(d, ImageSpan.ALIGN_BASELINE);
    final SpannableString spannableString = new SpannableString(string);
    spannableString.setSpan(imageSpan, string.length()-1, string.length(), 0);
    return spannableString;
}

removing ImageSpan.ALIGN_BASELINE sets it to align to the bottom which is also not my expected result.

--- Thank you user Lalit Poptani, I tried applying your answer---- after applying this, what happens is that the whole textview seems to have extra margin top.

before applying span:

This is the text*

after applying the SuperscriptSpanAdjuster

(some extra space)
This is the text*

My code:

String string = "This is the text*";
Drawable d = this.context.getResources().getDrawable(R.drawable.img_asterisk); 

d.setBounds(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight()); 

ImageSpan imageSpan = new ImageSpan(d, ImageSpan.ALIGN_BASELINE);
SuperscriptSpanAdjuster s = new SuperscriptSpanAdjuster(1.5);
final SpannableString spannableString = new SpannableString(string);
spannableString.setSpan(s, string.length() - 1, string.length(), 0);
spannableString.setSpan(imageSpan, string.length(), string.length() + 1, 0);
textView.setText(spannableString);

回答1:

What you can do is use a custom MetricAffectingSpan for maintaining its ratio like,

public class SuperscriptSpanAdjuster extends MetricAffectingSpan {
    double ratio = 0.5;

    public SuperscriptSpanAdjuster(double ratio) {
        this.ratio = ratio;
    }

    @Override
    public void updateDrawState(TextPaint paint) {
        paint.baselineShift += (int) (paint.ascent() * ratio);
    }

    @Override
    public void updateMeasureState(TextPaint paint) {
        paint.baselineShift += (int) (paint.ascent() * ratio);
    }
}

And the you can use SpannableString to apply asterisk to your String like,

SpannableString mString = new SpannableString("This is what I wanted*");
mString.setSpan(new SuperscriptSpanAdjuster(0.5), mString.length() - 1, 
                     mString.length(), SpannableString.SPAN_EXCLUSIVE_EXCLUSIVE);
mTextView.append("\n");
mTextView.append(mString);

This is append asterisk to your text as you required. And your output will be as,

来源：https://stackoverflow.com/questions/20392218/aligning-imagespan-to-the-top-of-the-textview

标签

android

textview

spannablestring