C# 将布局保存到位图（Xamarin）

我有布局，需要保存到位图

这是代码

public void Save()
{
    LinearLayout view = FindViewById<LinearLayout>(Resource.Id.badge);

    view.DrawingCacheEnabled = true;
    view.BuildDrawingCache();
    Bitmap layout = view.GetDrawingCache(true);

}

一切正常，位图2正在返回

但我还需要将其保存到SD

我是这样写的

public  Bitmap CreateBitmapFromView(View view, bool autoScale = true)
    {
        var wasDrawingCacheEnabled = view.DrawingCacheEnabled;
        view.DrawingCacheEnabled = true;
        view.BuildDrawingCache(autoScale);
        var bitmap2 = view.GetDrawingCache(autoScale);
        view.DrawingCacheEnabled = wasDrawingCacheEnabled;
        return bitmap2;

    }

public  Bitmap CreateBitmapFromView(View view, bool autoScale = true)
    {
        var wasDrawingCacheEnabled = view.DrawingCacheEnabled;
        view.DrawingCacheEnabled = true;
        view.BuildDrawingCache(autoScale);
        var bitmap2 = view.GetDrawingCache(autoScale);
        view.DrawingCacheEnabled = wasDrawingCacheEnabled;
        var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
        var filePath = System.IO.Path.Combine(sdCardPath, "test.png");
        var stream = new FileStream(filePath, FileMode.Create);
        bitmap2.Compress(Bitmap.CompressFormat.Png, 100, stream);
        return bitmap2;

    }

并且有这个错误

对象引用未设置为对象的实例

---

将其更改为以下内容：

public Bitmap CreateBitmapFromView(View view, bool autoScale = true)
{
    var wasDrawingCacheEnabled = view.DrawingCacheEnabled;
    view.DrawingCacheEnabled = true;
    view.BuildDrawingCache(autoScale);
    var bitmap = view.GetDrawingCache(autoScale);
    view.DrawingCacheEnabled = wasDrawingCacheEnabled;
    return bitmap;
}

更新

尝试将

var bitmap2

定义为全局变量

public  Bitmap CreateBitmapFromView(View view, bool autoScale = true)
    {
        var wasDrawingCacheEnabled = view.DrawingCacheEnabled;
        view.DrawingCacheEnabled = true;
        view.BuildDrawingCache(autoScale);
        view.DrawingCacheEnabled = wasDrawingCacheEnabled;
        var sdCardPath = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
        var filePath = System.IO.Path.Combine(sdCardPath, "test.png");
        var stream = new FileStream(filePath, FileMode.Create);
        bitmap2.Compress(Bitmap.CompressFormat.Png, 100, stream);
        return bitmap2;
    }

---

以及程序如何理解需要保存为btmap的布局？

public Bitmap CreateBitmapFromView（View-View，bool autoScale=true）

您可以在该方法中传递视图参数，因此我在方法中的视图将显示此

LinearLayout-View=FindViewById（Resource.Id.badge）我将传递线性布局？您可以将该视图传递给我在答案中编写的方法好的，我理解。还有一个问题，我需要将位图保存到SD我有代码
var sdCardPath=Android.OS.Environment.ExternalStorageDirectory.AbsolutePath；var filePath=System.IO.Path.Combine（sdCardPath，“test.png”）；var stream=newfilestream（filePath，FileMode.Create）；bitmap2.Compress（Bitmap.CompressFormat.Png，100，流）；stream.Close（）如何从您的方法保存位图？