从 edittext 中选定的文本中删除样式

我的应用程序应该允许用户在 Edittext 中设置输入或选定文本的样式。其中一些样式有下划线、删除线、粗体和斜体。它们很容易添加，但我不知道如何将它们移除 and 我如何确定该样式是否已添加到选定的文本。 添加样式的代码：

Spannable str = myEditText.getText();
    if (!SpannableUtils.isEmpty(str)) {
        str.setSpan(new StrikethroughSpan(), startSelection, endSelection,
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    }

我尝试使用removeSpan，但没有成功。 还尝试使用

        str.setSpan(new StyleSpan(android.graphics.Typeface.DEFAULT),
                startSelection, endSelection,
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

但它提出了错误：构造函数 StyleSpan(Typeface) 未定义。

我认为这堂课可以解决你的问题。

public class StyleSpanRemover {

    public void RemoveOne(Spannable spannable,
                          int startSelection, int endSelection, Class<?> style){

        ArrayList<SpanParts> spansParts = getSpanParts(spannable, startSelection, endSelection);
        removeOneSpan(spannable, startSelection, endSelection, style);
        restoreSpans(spannable, spansParts);
    }

    public void RemoveStyle(Spannable spannable,
              int startSelection, int endSelection, int styleToRemove){

        ArrayList<SpanParts> spansParts = getSpanParts(spannable, startSelection, endSelection);
        removeStyleSpan(spannable, startSelection, endSelection, styleToRemove);
        restoreSpans(spannable, spansParts);
    }

    public void RemoveAll(Spannable spannable, int startSelection, int endSelection){

        ArrayList<SpanParts> spansParts = getSpanParts(spannable, startSelection, endSelection);
        removeAllSpans(spannable, startSelection, endSelection);
        restoreSpans(spannable, spansParts);
    }

    protected void restoreSpans(Spannable spannable, ArrayList<SpanParts> spansParts){

        for (SpanParts spanParts : spansParts) {
            if(spanParts.part1.canAplly())
                spannable.setSpan(spanParts.part1.span, spanParts.part1.start,
                                  spanParts.part1.end,spanParts.span_flag);
            if(spanParts.part2.canAplly())
                spannable.setSpan(spanParts.part2.span, spanParts.part2.start,
                                  spanParts.part2.end, spanParts.span_flag);
        }
    }

    protected void removeAllSpans(Spannable spannable,int startSelection, int endSelection) {

        Object spansToRemove[] = spannable.getSpans(startSelection, endSelection, Object.class);
        for(Object span: spansToRemove){
            if(span instanceof CharacterStyle)
                spannable.removeSpan(span);
        }
    }

    protected void removeOneSpan(Spannable spannable,int startSelection, int endSelection,
                           Class<?> style) {

        CharacterStyle spansToRemove[] = spannable.getSpans(startSelection, endSelection, CharacterStyle.class);
        for(CharacterStyle span: spansToRemove){
            if(span.getUnderlying().getClass() == style )
                spannable.removeSpan(span);
        }
    }

    protected void removeStyleSpan(Spannable spannable, int startSelection,
        int endSelection, int styleToRemove) {

        MetricAffectingSpan spans[] = spannable.getSpans(startSelection, endSelection, MetricAffectingSpan.class);
        for(MetricAffectingSpan span: spans){
            int stylesApplied = 0;  
            int stylesToApply;
            int spanStart;
            int spanEnd;
            int spanFlag;
            Object spanUnd = span.getUnderlying();
            if(spanUnd instanceof StyleSpan){
                spanFlag = spannable.getSpanFlags(spanUnd);
                stylesApplied = ((StyleSpan) spanUnd).getStyle();
                stylesToApply = stylesApplied & ~styleToRemove;

                spanStart = spannable.getSpanStart(span);
                spanEnd = spannable.getSpanEnd(span);
                if(spanEnd >= 0 && spanStart >= 0){
                    spannable.removeSpan(span);
                    spannable.setSpan(new StyleSpan(stylesToApply), spanStart, spanEnd,spanFlag);
                }
            }
        }
    }

    protected ArrayList<SpanParts> getSpanParts(Spannable spannable,
                                              int startSelection,int endSelection){

        ArrayList<SpanParts> spansParts = new ArrayList<SpanParts>();
        Object spans[] = spannable.getSpans(startSelection, endSelection, Object.class);
        for(Object span: spans){
            if(span instanceof CharacterStyle){
                SpanParts spanParts = new SpanParts();
                int spanStart = spannable.getSpanStart(span);
                int spanEnd = spannable.getSpanEnd(span);
                if(spanStart == startSelection && spanEnd == endSelection) continue;
                spanParts.span_flag = spannable.getSpanFlags(span);
                spanParts.part1.span = CharacterStyle.wrap((CharacterStyle) span);
                spanParts.part1.start = spanStart;
                spanParts.part1.end = startSelection;
                spanParts.part2.span = CharacterStyle.wrap((CharacterStyle) span);
                spanParts.part2.start = endSelection;
                spanParts.part2.end = spanEnd;
                spansParts.add(spanParts);
            }
        }
        return spansParts;
    }

    private class SpanParts{
        int span_flag;
        Part part1;
        Part part2;
        SpanParts() {
            part1 = new Part();
            part2 = new Part();
        }
    }
    private class Part{
        CharacterStyle span;
        int start;
        int end;
        boolean canAplly() {
            return start < end;
        }
    }
}

如何使用：

int startSelection=editText.getSelectionStart();
int endSelection=editText.getSelectionEnd();
Spannable spannable = editText.getText();

StyleSpanRemover spanRemover = new StyleSpanRemover();
// to remove all styles
spanRemover.RemoveAll(spannable,startSelection,endSelection);
//to remove only StrikethroughSpan style use:
spanRemover.RemoveOne(spannable,startSelection,endSelection,StrikethroughSpan.class);
//to remove one StyleSpan use:
spanRemover.RemoveStyle(spannable,startSelection,endSelection,Typeface.BOLD)