Xamarin- No buttons or text shown

I just downloaded Xamarin for Visual Studio for the first time, connect my Inco tablet. Create a project Blank App (android) and in the main.axml drag a button and a text, but when you run the application on my tablet you could only see the name of the solution along with the default logo, a black background and nothing else , without button or text. Although in the design mode of the main.axml if they are clearly seen No errors were shown when compiling. Configure in Properties the correct android version that my KitKat tablet uses. Could someone help me solve this problem?

As seen in the main.axml

But on the tablet it looks like this:

Code:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
    android:text="Hello World"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/button1"
    android:layout_marginBottom="68.0dp"
    android:layout_marginTop="0.0dp"
    android:layout_marginRight="92.0dp"
    android:layout_marginLeft="62.0dp" />
<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/editText1"
    android:text="nanana" /></LinearLayout>