ImageSpan和TextView在垂直方向,SPAN_EXCLUSIVE_EXCLUSIVE等几个属性

默认的ImageSpan只能实现和文字向上(ImageSpan.ALIGN_BASELINE)和向下(ImageSpan.ALIGN_BOTTOM)对齐，所以是无法实现ImageSpan和文字垂直方向在一条直线上的。

当然也是能实现的，自定义一一个ImageSpan就行，下面是代码，来自So。

public class CenteredImageSpan extends ImageSpan
{
    private WeakReference mDrawableRef;

    public CenteredImageSpan(Drawable drawableRes)
    {
        super(drawableRes);
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm)
    {
        Drawable d = getCachedDrawable();
        Rect rect = d.getBounds();

        if (fm != null)
        {
            Paint.FontMetricsInt pfm = paint.getFontMetricsInt();
            // keep it the same as paint's fm
            fm.ascent = pfm.ascent;
            fm.descent = pfm.descent;
            fm.top = pfm.top;
            fm.bottom = pfm.bottom;
        }

        return rect.right;
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom,
            Paint paint)
    {
        Drawable b = getCachedDrawable();
        canvas.save();

        int drawableHeight = b.getIntrinsicHeight();
        int fontAscent = paint.getFontMetricsInt().ascent;
        int fontDescent = paint.getFontMetricsInt().descent;
        int transY = bottom - b.getBounds().bottom + (drawableHeight - fontDescent + fontAscent) / 2;

        canvas.translate(x, transY);
        b.draw(canvas);
        canvas.restore();
    }

    // Redefined locally because it is a private member from
    private Drawable getCachedDrawable()
    {
        WeakReference wr = mDrawableRef;
        Drawable d = null;

        if (wr != null)
            d = wr.get();

        if (d == null)
        {
            d = getDrawable();
            mDrawableRef = new WeakReference(d);
        }

        return d;
    }
}

在做上面的需求的时候，一直不太明白SpannableString的一些使用，

SpannableString result1 = new SpannableString(title);
ForegroundColorSpan span = new ForegroundColorSpan(Color.RED);
result1.setSpan(span, 2, 4, Spannable.SPAN_INCLUSIVE_INCLUSIVE);

但是一直不明白SPAN_INCLUSIVE_INCLUSIVE等属性的区别。一个demo就解决了。

相应的java代码。

SpannableString ss1 = new SpannableString("text4: Click here to dial the phone.");
        ss1.setSpan(new StyleSpan(Typeface.BOLD), 0, 6, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        ss1.setSpan(new URLSpan("tel:4155551212"), 13, 17, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

        SpannableString ss2 = new SpannableString("text4: Click here to dial the phone.");
        ss2.setSpan(new StyleSpan(Typeface.BOLD), 0, 6, Spanned.SPAN_EXCLUSIVE_INCLUSIVE);
        ss2.setSpan(new URLSpan("tel:4155551212"), 13, 17, Spanned.SPAN_EXCLUSIVE_INCLUSIVE);

        SpannableString ss3 = new SpannableString("text4: Click here to dial the phone.");
        ss3.setSpan(new StyleSpan(Typeface.BOLD), 0, 6, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
        ss3.setSpan(new URLSpan("tel:4155551212"), 13, 17, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

        SpannableString ss4 = new SpannableString("text4: Click here to dial the phone.");
        ss4.setSpan(new StyleSpan(Typeface.BOLD), 0, 6, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        ss4.setSpan(new URLSpan("tel:4155551212"), 13, 17, Spanned.SPAN_INCLUSIVE_INCLUSIVE);

        ((EditText) findViewById(R.id.text1)).setText(ss1);
        // ((EditText)
        // findViewById(R.id.text1)).setMovementMethod(LinkMovementMethod.getInstance());

        ((EditText) findViewById(R.id.text2)).setText(ss2);
        // ((EditText)
        // findViewById(R.id.text2)).setMovementMethod(LinkMovementMethod.getInstance());

        ((EditText) findViewById(R.id.text3)).setText(ss3);
        // ((EditText)
        // findViewById(R.id.text3)).setMovementMethod(LinkMovementMethod.getInstance());

        ((EditText) findViewById(R.id.text4)).setText(ss4);
        // ((EditText)
        // findViewById(R.id.text4)).setMovementMethod(LinkMovementMethod.getInstance());

结果：

它是用来标识在 Span 范围内的文本前后输入新的字符时是否把它们也应用这个效果。即代表的前后的文字是否也一样，哈哈。