android binder如何实现异步

VB.NET创建文件夹方法如下：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Try
        If Directory.Exists(TextBox1.Text) Then
            MsgBox("此目录存在")
            Return
        End If
        Dim di As DirectoryInfo = Directory.CreateDirectory(TextBox1.Text)
        MsgBox("创建成功")
    Catch ex As Exception
        MsgBox("文件异常", ex.ToString)
    End Try
End Sub

由下图可知，已创建新目录成功