Android：通过SpannableString为TextView设置丰富的显示效果

在使用TextView的过程中，有时候会需要将一串文本中的部分文字做特别的显示效果处理，比如加粗、改变颜色、加着重标识、超链接等等，我们可以通过多个TextView拼凑来实现，但如果需要特殊处理的内容在整个文本的中间，用多个TextView拼凑实在是太麻烦、太Low了，Android提供的SpannableString类能够很好地解决这个问题，SpannableString结合下面各种以Span结尾的类可以做出丰富多样的显示效果。

本文结合平时工作情况，写了一个SpannableUtils工具类，方便今后使用，SpannableUtils.java具体代码如下，如果要对同一串文本同时设置多种显示效果，可以考虑改造该类实现：

/**
 * Spannable工具类，用于设置文字的前景色、背景色、Typeface、粗体、斜体、字号、超链接、删除线、下划线、上下标等
 * 
 * */
public class SpannableUtils {
	private SpannableUtils( ){
		
	}
	
	/**
	 * 改变字符串中某一段文字的字号
	 * setTextSize("",24,0,2) = null;
	 * setTextSize(null,24,0,2) = null;
	 * setTextSize("abc",-2,0,2) = null;
	 * setTextSize("abc",24,0,4) = null;
	 * setTextSize("abc",24,-2,2) = null;
	 * setTextSize("abc",24,0,2) = normal string
	 * */
	public static SpannableString setTextSize( String content, int startIndex, int endIndex, int fontSize ){
		if( TextUtils.isEmpty( content ) || fontSize <= 0 || startIndex >= endIndex || startIndex < 0 || endIndex >= content.length( ) ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan( new AbsoluteSizeSpan( fontSize ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE );
		
		return spannableString;
	}
	
	public static SpannableString setTextSub( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan( new SubscriptSpan( ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE );
		
		return spannableString;
	}
	
	public static SpannableString setTextSuper( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan( new SuperscriptSpan( ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE );
		
		return spannableString;
	}
	
	public static SpannableString setTextStrikethrough( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new StrikethroughSpan(), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextUnderline( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new UnderlineSpan(), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextBold( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new StyleSpan(android.graphics.Typeface.BOLD), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextItalic( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new StyleSpan(android.graphics.Typeface.ITALIC), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextBoldItalic( String content, int startIndex, int endIndex ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new StyleSpan(android.graphics.Typeface.BOLD_ITALIC), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextForeground( String content, int startIndex, int endIndex, int foregroundColor ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new ForegroundColorSpan( foregroundColor ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextBackground( String content, int startIndex, int endIndex, int backgroundColor ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new BackgroundColorSpan( backgroundColor ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	/**
	 * 设置文本的超链接
	 * @param content 需要处理的文本
	 * @param startIndex
	 * @param endIndex 被处理文本中需要处理字串的开始和结束索引
	 * @param url 文本对应的链接地址，需要注意格式：
	 * （1）电话以"tel:"打头，比如"tel:02355692427"
	 * （2）邮件以"mailto:"打头，比如"mailto:[email protected]"
	 * （3）短信以"sms:"打头，比如"sms:02355692427"
	 * （4）彩信以"mms:"打头，比如"mms:02355692427"
	 * （5）地图以"geo:"打头，比如"geo:68.426537,68.123456"
	 * （6）网络以"http://"打头，比如"http://www.google.com"
	 * */
	public static SpannableString setTextURL( String content, int startIndex, int endIndex, String url ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new URLSpan( url ), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
	
	public static SpannableString setTextImg( String content, int startIndex, int endIndex, Drawable drawable ){
		if( TextUtils.isEmpty( content ) || startIndex < 0 || endIndex >= content.length( ) || startIndex >= endIndex ){
			return null;
		}
		
		SpannableString spannableString = new SpannableString( content );
		spannableString.setSpan(new ImageSpan(drawable), startIndex, endIndex, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
		
		return spannableString;
	}
}

本例Demo可以在此下载：Spannable实例