Android缩进和悬挂缩进

我有兴趣拥有一系列TextView,最终有一个悬挂缩进.通过CSS执行此操作的标准方法是将边距设置为X像素,然后将文本缩进设置为-X像素.显然我可以用“ android：layout_marginLeft =”Xdp“来做第一个,但我不知道如何在TextView上施加-X像素.任何想法或解决方法？我感谢任何建议.

解决方法

弄清楚如何使悬挂缩进适用于我自己的项目.基本上你需要使用android.text.style.LeadingMarginSpan,并通过代码将它应用到你的文本. LeadingMarginSpan.Standard采用完整缩进(1个参数)或悬挂缩进(2个参数)构造函数,并且需要为要应用样式的每个子字符串创建新的Span对象. TextView本身也需要将其BufferType设置为SPANNABLE.

如果必须多次执行此操作,或者希望在样式中包含缩进,请尝试创建TextView的子类,该子类采用自定义缩进属性并自动应用跨度.我从Statically Typed博客和SO问题Declaring a custom android UI element using XML中获得了很多用途.

在TextView中：

// android.text.style.CharacterStyle is a basic interface,you can try the 
// TextAppearanceSpan class to pull from an existing style/theme in XML

CharacterStyle style_char = 
    new TextAppearanceSpan (getContext(),styleId);
float textSize = style_char.getTextSize();

// indentF roughly corresponds to ems in dp after accounting for 
// system/base font scaling,you'll need to tweak it

float indentF = 1.0f;
int indent = (int) indentF;
if (textSize > 0) {
    indent = (int) indentF * textSize;
}

// android.text.style.ParagraphStyle is a basic interface,but
// LeadingMarginSpan handles indents/margins
// If you're API8+,there's also LeadingMarginSpan2,which lets you 
// specify how many lines to count as "first line hanging"

ParagraphStyle style_para = new LeadingMarginSpan.Standard (indent);

String unstyledSource = this.getText();

// SpannableString has mutable markup,with fixed text
// SpannableStringBuilder has mutable markup and mutable text

SpannableString styledSource = new SpannableString (unstyledSource);
styledSource.setSpan (style_char,styledSource.length(),Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
styledSource.setSpan (style_para,Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

// *or* you can use Spanned.SPAN_ParaGRAPH for style_para,but check
// the docs for usage

this.setText (styledSource,BufferType.SPANNABLE);