I know that when you set
tools:text="Sample text"
within a TextView
, you'll see the sample text in Preview mode in Android Studio, but not within the actual app. I'd like to do this for items in a RecyclerView
, but I can't seem to be able to. Here's what I've done so far:
In the RecyclerView (named content_feed):
tools:listitem="@layout/cell_feed"
In the cell (name cell_feed):
tools:showIn="@layout/content_feed"
Here are the xml
files:
cell_feed.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="@dimen/height_feed_cell"
android:layout_marginLeft="@dimen/margin_feed_cell"
android:layout_marginRight="@dimen/margin_feed_cell"
android:orientation="horizontal"
tools:showIn="@layout/content_feed">
<LinearLayout
android:id="@+id/timeLayouts"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:alpha="@dimen/alpha_feed_secondary_text"
android:textSize="@dimen/size_feed_secondary_text"
android:id="@+id/startTimeText"
tools:text="8:00 AM"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:alpha="@dimen/alpha_feed_secondary_text"
android:textSize="@dimen/size_feed_secondary_text"
android:id="@+id/endTimeText"
tools:text="10:00 AM"/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="@dimen/margin_feed_cell_text"
android:layout_toRightOf="@+id/timeLayouts"
android:layout_centerVertical="true"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="@dimen/margin_bottom_feed_cell_title"
android:textSize="@dimen/size_feed_cell_title"
android:textStyle="bold"
android:id="@+id/titleText"
tools:text="Event title"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:alpha="@dimen/alpha_feed_secondary_text"
android:textSize="@dimen/size_feed_secondary_text"
android:id="@+id/captionText"
tools:text="Event caption"/>
</LinearLayout>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginLeft="@dimen/margin_feed_cell_text"
tools:text=""/>
</RelativeLayout>
content_feed.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/feedRecycler"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:listitem="@layout/cell_feed"
tools:showIn="@layout/activity_feed"/>
The feature you want is called "Support for sample data" and was recently announced in Google I/O 2017 event. This is a direct link to the exact minute where Tor Norbye introduces the new feature.
For example, applying following to the layout item:
tools:text="@tools:sample/lorem"
will result in following output in Preview window:
Applying this:
tools:text="@tools:sample/date_day_of_week"
will result in this output in Preview window:
You can also populate it with your custom data. This blog post demonstrates a full example of how to do that. First, you right click on your app module and choose New | Sample Data directory
.
Then you would create for example an activity_log.json
file in the sampledata
directory with following content:
{
"activities" : [
{
"icon": "@sample/activity_icons[ic_biking.png]",
"description": "Biking",
"location" : "Pleasant Hill, CA",
"distance": "48 miles",
"date": "Yesterday"
},
// other items here
]
}
Then you can apply this data to your layout this way:
tools:src="@sample/activity_log.json/activities/icon"
tools:src="@sample/activity_log.json/activities/distance"
This will result in following output in Preview window:
For more details on the topic have a look at "Tool Time" series of posts by Mark Allison.
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