Android的SpannableString设置背景的背后文本的一部分 [英] Android SpannableString set background behind part of text

问题描述

我想创建类似的东西因为看到这个图片：

我设法创建SpannableStringBuilder evertyhing，除了橙色的圆角矩形。我可以设置背景与BackgroundColorSpan的颜色，但我不能找到一种方法，使四舍五入。任何想法我怎么能做到这一点？

在此先感谢！

编辑： 我使用Xamarin.Android，但这里是我的code：

  stringBuilder.SetSpan（新BackgroundColorSpan（Application.Context.Resources.GetColor（Resource.Color.orangeColor）），stringBuilder.Length（） - 长度，stringBuilder.Length（），SpanTypes .ExclusiveExclusive）;
 

解决方案

我设法解决我的问题的基础上，pskink的建议。 这是我的类：

 公共类RoundedBackgroundSpan：ReplacementSpan
{
    公众覆盖无效抽奖（画布油画，ICharSequence文字，诠释开始，诠释年底，浮法X，INT顶部，INT Y，INT底部，油漆涂料）
    {
        VAR RECT =新RectF（X，顶部，X + MeasureText（涂料，文本，开始，结束），底部）;
        paint.Color = Application.Context.Resources.GetColor（Resource.Color.nextTimeBackgroundColor）;
        canvas.DrawRoundRect（矩形， Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue), Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue),涂料）;
        paint.Color = Application.Context.Resources.GetColor（Resource.Color.nextTimeTextColor）;
        canvas.DrawText（文本，开始，结束，X，Y，油漆）;
    }

    公众覆盖INT的getSize（油漆涂料，ICharSequence文字，诠释开始，诠释年底，Paint.FontMetricsInt FM）
    {
        返回Math.Round（MeasureText（油漆，文本，开始，结束））;
    }

    私人浮动MeasureText（油漆涂料，ICharSequence文字，诠释开始，诠释完）
    {
        返回paint.MeasureText（文本，开始，结束）;
    }
}
 

实例：

  VAR的StringBuilder =新SpannableStringBuilder（）;
VAR stringToAppend =世界你好;
stringBuilder.Append（stringToAppend）;
stringBuilder.SetSpan（新RoundedBackgroundSpan（），stringBuilder.Length（） -  stringToAppend.Length，stringBuilder.Length（），SpanTypes.ExclusiveExclusive）;
 

I would like to create something similar as seen on this image:

I managed to create evertyhing with SpannableStringBuilder, except the orange rounded rectangle. I can set the background to that color with BackgroundColorSpan, but I can't find a way to make it rounded. Any ideas how can I achieve this?

Thanks in advance!

EDIT: I'm using Xamarin.Android, but here is my code:

stringBuilder.SetSpan(new BackgroundColorSpan(Application.Context.Resources.GetColor(Resource.Color.orangeColor)), stringBuilder.Length() - length, stringBuilder.Length(), SpanTypes.ExclusiveExclusive);

解决方案

I managed to solve my problem, based on pskink's suggestion. Here is my class:

public class RoundedBackgroundSpan : ReplacementSpan
{
    public override void Draw(Canvas canvas, ICharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint)
    {
        var rect = new RectF(x, top, x + MeasureText(paint, text, start, end), bottom);
        paint.Color = Application.Context.Resources.GetColor(Resource.Color.nextTimeBackgroundColor);
        canvas.DrawRoundRect(rect, Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue), Application.Context.Resources.GetDimensionPixelSize(Resource.Dimension.localRouteDetailsRoundRectValue), paint);
        paint.Color = Application.Context.Resources.GetColor(Resource.Color.nextTimeTextColor);
        canvas.DrawText(text, start, end, x, y, paint);
    }

    public override int GetSize(Paint paint, ICharSequence text, int start, int end, Paint.FontMetricsInt fm)
    {
        return Math.Round(MeasureText(paint, text, start, end));
    }

    private float MeasureText(Paint paint, ICharSequence text, int start, int end)
    {
        return paint.MeasureText(text, start, end);
    }
}

Example usage:

var stringBuilder = new SpannableStringBuilder();
var stringToAppend = "hello world";
stringBuilder.Append(stringToAppend);
stringBuilder.SetSpan(new RoundedBackgroundSpan(), stringBuilder.Length() - stringToAppend.Length, stringBuilder.Length(), SpanTypes.ExclusiveExclusive);

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