reddead reddead - 5 months ago 109
Android Question

Android Studio - Cannot Drag and Drop Button

I just created a new project, blank activity. If I go into the interface for the activity_main.xml I cannot drag and drop any widgets. I tried changing the theme, still nothing. Here is my activity_main.xml and manifest files.

Manifest:

<?xml version="1.0" encoding="utf-8"?>




<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>




activity_main.xml:



<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">

<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_main" />

<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
android:src="@android:drawable/ic_dialog_email" />



Answer

Android Studio changed the layout activity_main.xml and made it as a container for things like FloatingActionButton, ToolBar.. so you can't drag and drop buttons there. They created another xml file called content_main.xml where you can add all your other views. They include the content_main inside activity_main by

<include layout="@layout/content_main" />