Android：SpannableString使用详解

在Android开发过程中，我们有时会需要TextView 显示各种格式的文本，包括字体颜色，大小，下划线，表情符号等等。对于这种需求，我们应该如何实现呢？答案是：SpannableString。
我们可以通过SpannableString来实现各种格式的文本。它的使用非常简单，这里不多介绍了。直接看代码会更加的直观。

效果

我们先来看一下运行的效果。

代码如下

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.nxiangbo.spansdemo.MainActivity" >

    <TextView  android:id="@+id/tv_content" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="5dp" android:text="@string/content"/>

</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity {
    private static final String TAG = "MainActivity";

    private TextView mText;
    private SpannableString mSpannableString;

    private String mContent;

    private static final String itallic = "三月七日沙湖道中遇雨。雨具先去，同行皆狼狈，余独不觉。已而遂晴，故作此 ";
    private static final String bold = "谁怕？ 一蓑烟雨任平生";
    private static final String underline = "莫听穿林打叶声";
    private static final String subscript = "徐行";
    private static final String superscript = "轻胜马";
    private static final String backgroundCorlor = "料峭春风吹酒醒";
    private static final String foregroundColor = "微冷";
    private static final String relativeSize = "山头";
    private static final String maskFilter = "却相迎";
    private static final String scaleX = "回首";
    private static final String strikeThrough = "萧瑟处";
    private static final String blurMaskFilter = "归去";
    private static final String image = "苏轼";
    private static final String quote = "人间不可无一，难能有二";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mText = (TextView) findViewById(R.id.tv_content);
        mContent = getResources().getString(R.string.content);
        mSpannableString = new SpannableString(mContent);

        Log.e(TAG, mContent.length()+"mContent.length");

        setItallic(itallic);
        setBold(bold);
        setUnderLine(underline);
        setSubscript(subscript);
        setSuperscript(superscript);
        setBackgroundColor(backgroundCorlor);
        setForegroundColor(foregroundColor);
        setRelativeSize(relativeSize);
        setMaskFilter(maskFilter);
        setScaleX(scaleX);
        setStrikeThrough(strikeThrough);
        setBlurMaskFilter(blurMaskFilter);
        setImage(image);
        setQuote(quote);
        mText.setText(mSpannableString);

    }

    //将"苏轼"替换成一张图片
    @SuppressLint("NewApi")
    private void setImage(String text) {
        Object span = null;
        span = new ImageSpan(this,R.drawable.demo);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //将字体设置为模糊效果
    private void setBlurMaskFilter(String text) {
        Object span = null;
        span = new MaskFilterSpan(new BlurMaskFilter(5, BlurMaskFilter.Blur.OUTER));
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置删除线
    private void setStrikeThrough(String text) {
        Object span = null;
        span = new StrikethroughSpan();
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置字体在水平方向上放大两倍
    private void setScaleX(String text) {
        Object span = null;
        span = new ScaleXSpan(2.0f);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置字体为浮雕形式的
    private void setMaskFilter(String text) {
        Object span = null;
        span = new MaskFilterSpan(new EmbossMaskFilter(new float[] { 1, 5, 1 }, 0.4f, 6, 3.5f));
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;

        ForegroundColorSpan fg = new ForegroundColorSpan(Color.RED);
        StyleSpan style = new StyleSpan(android.graphics.Typeface.BOLD);
        mSpannableString.setSpan(fg, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        mSpannableString.setSpan(style, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置字体大小的原来大两倍
    private void setRelativeSize(String text) {
        Object span = null;
        span = new RelativeSizeSpan(2.0f);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置前景颜色
    private void setForegroundColor(String text) {
        Object span = null;
        span = new ForegroundColorSpan(Color.BLUE);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置背景颜色
    private void setBackgroundColor(String text) {
        Object span = null;
        span = new BackgroundColorSpan(Color.YELLOW);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }



    //设置黑体
    private void setBold(String text){
        Object span = null;
        span = new StyleSpan(android.graphics.Typeface.BOLD);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置斜体
    private void setItallic(String text){
        Object span = null;
        span = new StyleSpan(android.graphics.Typeface.ITALIC);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;

        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置引用
    private void setQuote(String text){
        Object span = null;
        span = new CustomQuoteSpan(Color.BLUE);
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置下划线
    private void setUnderLine(String text){
        Object span = new UnderlineSpan();
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置下标
    private void setSubscript(String text){
        Object span = new SubscriptSpan();
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

    //设置上标
    private void setSuperscript(String text){
        Object span = new SuperscriptSpan();
        WordPosition position = getWordPosition(text);
        int textStart = position.start;
        int textEnd = position.end;
        mSpannableString.setSpan(span, textStart, textEnd, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
    }


    private WordPosition getWordPosition(String text) {
        int start = mContent.indexOf(text);
        int end = start + text.length();
        return new WordPosition(start, end);
    }

    private static final class WordPosition {
        int start;
        int end;

        private WordPosition(int start, int end) {
            this.start = start;
            this.end = end;
        }

        @Override
        public String toString() {
            return "WordPosition{" +
                    "start=" + start +
                    ", end=" + end +
                    '}';
        }
    }



}

源码下载地址

参考文章

1. Spans, a Powerful Concept.
2. 【译】Spans，一个强大的概念(上篇文章的中文译文)