为什么我不能在活动中放置小部件？ （Android）

Question

I have created a Google Maps activity called 'PechhulpActivity' and i want to place a button over it. But if i want to edit the activity it gives me the error about fragment tags:

A <fragment> tag allows a layout file to dynamically include different
layouts at runtime. At layout editing time the specific layout to be
used is not known. You can choose which layout you would like previewed
while editing the layout.

Here is a screenshot of my layout folder structure, first i thought i was missing a file like content_pechhulp.xml. If so, how can i create the correct one? I want to customize the Google maps activity like the info window and i want a button inside of it etc. I hope you guys can help me out.

Edit: (activity_pechhulp.xml)

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.doppler.stackingcoder.pechhulp.PechhulpActivity" />

Answer 1

Try using RelativeLayout as Parent and then add the child with fragment and another view like TextView or Button. It will placed above the map.

Answer 2

use a Relativelayout or FrameLayout as parrent for this

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:map="http://schemas.android.com/apk/res-auto"
            xmlns:tools="http://schemas.android.com/tools"
            android:layout_width="match_parent"
            android:layout_height="match_parent">
            <fragment
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.SupportMapFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
          tools:context="com.doppler.stackingcoder.pechhulp.PechhulpActivity"/>
            <Button 
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:text="@string/your_string_value"/>
   </RelativeLayout>