FragmentPagerAdapter title设置文本属性 比如最大行数 设置超过maxems=7时换行

您可以在FragmentPagerAdapter的getPageTitle()方法中返回SpannableString对象，并在其中设置您想要的文本属性，例如最大行数和换行。以下是一个示例代码：

@Override
public CharSequence getPageTitle(int position) {
    String title = "Your Title Here";
    SpannableString spannableString = new SpannableString(title);
    int maxLines = 2;
    int maxEms = 7;
    TextUtils.TruncateAt truncateAt = TextUtils.TruncateAt.END;
    spannableString = new SpannableString(title);
    spannableString.setSpan(new TextAppearanceSpan(context, R.style.TitleTextStyle), 0, title.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    spannableString.setSpan(new MaxLinesSpan(maxLines), 0, title.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    spannableString.setSpan(new MaxEmsSpan(maxEms), 0, title.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    spannableString.setSpan(new EllipsesSpan(truncateAt), 0, title.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    return spannableString;
}

其中，TitleTextStyle是您定义的文本样式，MaxLinesSpan、MaxEmsSpan和EllipsesSpan是自定义的Span类，用于设置最大行数、最大字符数和省略号。以下是这些Span类的示例实现：

public class MaxLinesSpan extends MetricAffectingSpan {
    private int maxLines;

    public MaxLinesSpan(int maxLines) {
        this.maxLines = maxLines;
    }

    @Override
    public void updateDrawState(TextPaint tp) {
        // Do nothing
    }

    @Override
    public void updateMeasureState(TextPaint p) {
        p.setTextSize(p.getTextSize());
        p.setFakeBoldText(p.isFakeBoldText());
        p.setUnderlineText(p.isUnderlineText());
        p.setColor(p.getColor());
        p.setTypeface(p.getTypeface());
        p.setTextScaleX(p.getTextScaleX());
        p.setTextSkewX(p.getTextSkewX());
        p.setStrikeThruText(p.isStrikeThruText());
        p.setElegantTextHeight(p.isElegantTextHeight());
        p.setSubpixelText(p.isSubpixelText());
        p.setHinting(p.getHinting());
        p.setMetrics(p.getFontMetricsInt());
        p.setShadowLayer(p.getShadowLayerRadius(), p.getShadowLayerDx(), p.getShadowLayerDy(), p.getShadowLayerColor());
        p.setLineSpacing(p.getLineSpacingExtra(), p.getLineSpacingMultiplier());
        p.setLetterSpacing(p.getLetterSpacing());
        p.setMaxLines(maxLines);
    }
}

public class MaxEmsSpan extends MetricAffectingSpan {
    private int maxEms;

    public MaxEmsSpan(int maxEms) {
        this.maxEms = maxEms;
    }

    @Override
    public void updateDrawState(TextPaint tp) {
        // Do nothing
    }

    @Override
    public void updateMeasureState(TextPaint p) {
        p.setTextSize(p.getTextSize());
        p.setFakeBoldText(p.isFakeBoldText());
        p.setUnderlineText(p.isUnderlineText());
        p.setColor(p.getColor());
        p.setTypeface(p.getTypeface());
        p.setTextScaleX(p.getTextScaleX());
        p.setTextSkewX(p.getTextSkewX());
        p.setStrikeThruText(p.isStrikeThruText());
        p.setElegantTextHeight(p.isElegantTextHeight());
        p.setSubpixelText(p.isSubpixelText());
        p.setHinting(p.getHinting());
        p.setMetrics(p.getFontMetricsInt());
        p.setShadowLayer(p.getShadowLayerRadius(), p.getShadowLayerDx(), p.getShadowLayerDy(), p.getShadowLayerColor());
        p.setEms(maxEms);
    }
}

public class EllipsesSpan extends ReplacementSpan {
    private TextUtils.TruncateAt truncateAt;

    public EllipsesSpan(TextUtils.TruncateAt truncateAt) {
        this.truncateAt = truncateAt;
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {
        return (int) 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) {
        canvas.drawText(TextUtils.ellipsize(text, paint, x, truncateAt), x, y, paint);
    }
}