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When I add the RecyclerView to the layout, it shows up as a blank screen. Is there a way, such as through the tools namespace, to show a preview of the content of the RecyclerView?

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5 Answers 5

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720

@oRRs is right !

I'm using Android Studio 1.4 RC2 and you can now specify any custom layout.

I tried a custom CardView and it works.

tools:listitem="@android:layout/simple_list_item_checked"
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11 Comments

See @oRRs comment : tools:listitem="@android:layout/simple_list_item_checked"
is there any way to preview in grid mode?
@sajad try this app:layoutManager="GridLayoutManager" tools:listitem="@layout/layout_list_item_select_seat" app:spanCount="5"
If you also wish to set the orientation to be horizontal , you can: tools:orientation="horizontal"
In addition to specifying tools:orientation="horizontal" or android:orientation="horizontal" I also had to specify app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager" as per stackoverflow.com/questions/35681433/…
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Android tools and LayoutManager

tools namespace enables design-time features (such as which layout to show in a fragment) or compile-time behaviors (such as which shrinking mode to apply to your XML resources) It is really powerful feature that is developing and allows you not compile code every time to see changes

AndroidX[About] and GridLayoutManager

implementation 'androidx.recyclerview:recyclerview:1.1.0' 
<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:layoutManager="androidx.recyclerview.widget.GridLayoutManager" tools:listitem="@layout/item" tools:itemCount="10" tools:orientation="vertical" tools:scrollbars="vertical" tools:spanCount="3"/>

Support library and LinearLayoutManager

implementation 'com.android.support:recyclerview-v7:28.0.0' 
 <android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="wrap_content" tools:layoutManager="android.support.v7.widget.LinearLayoutManager" tools:listitem="@layout/item" tools:itemCount="3" tools:orientation="horizontal" tools:scrollbars="horizontal" />

Another cool feature that was introduced in Android studio 3.0 is predefining a data through the tools attributes, to visualised easily your layout structure using @tools:sample/* resources

item.xml

<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="100dp" android:layout_height="150dp" android:layout_marginRight="15dp" android:layout_marginBottom="10dp" android:orientation="vertical" tools:background="@tools:sample/backgrounds/scenic"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:textColor="@color/colorWhite" tools:text="@tools:sample/first_names" /> </FrameLayout>

Simulator results:

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5 Comments

This should be marked as answer, as it is detailed and compatible with RecylerView. ListViews are not used at all nowadays.
I had to switch to fewer attribute tab in the attribute area to be able to see the listitem option, I could simply just type it into the xml code!
If you are using your own list item layout and you are only seeing one(1) list item then check that layout_height="wrap_content" on your layout.
Interistingly, it only works for me if I use ListView but not with a RecyclerView. Any ideas¿? I copy pasted to be sure I wasn't messing things up with my RecyclerView. But actually it works, so it is a valid XML.
"@tools:sample/*" is a reserver android resource type of placeholder data you can inject into your layouts. last_names - Common last names. The full official doc - developer.android.com/studio/write/…
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First, add the following line in your item XML to made a preview of your list while you edit your item:

tools:showIn="@layout/activity_my_recyclerview_item"

And them, add the following line in your RecyclerView XML to preview how your item will look in your list:

tools:listitem="@layout/adapter_item"
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showIn is very nice to use
4

If you have already a custom_item layout:

<androidx.recyclerview.widget.RecyclerView android:id="@+id/recyclerView" ... ... **tools:listitem="@layout/name_of_your_custom_item_view"** ...> </androidx.recyclerview.widget.RecyclerView>
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3

As of Android Studio 1.3.1 it shows default list items in the preview but it doesn't let yout specify your own yet. Hopefully, it will come.

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In AS 1.4 you get to select from a few predefined layouts, e.g.: tools:listitem="@android:layout/simple_list_item_checked". Just right-click the RecyclerView in the layout editor and choose "Preview list content". Unfortunately, you still cannot use it for your own layouts, at least for me it's throwing a rendering error.

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