I have a layout that contains a ScrollView with a LinearLayout and its children: a PercentRelativeLayout 23.2.1, another LinearLayout below it and another PercentRelativeLayout after that. Inside the middle LinearLayout I have a RecyclerView (LinearLayoutManager, vertical). You may see an example below.
At runtime, when I fill the RecyclerView with data, its size grows since I start with an empty one. Once its height changes to exceed the screen size, the upper image of a car (id = car), that has a percentage value as its height, is gone from a screen completely. When I scroll this screen up and down, I reach both top and bottom edges and don't see the image.
I also have percentage values in one more place in this layout, and they define marginTop. These margins disappear as well. Width-dependent percentage values work fine. The java code does not contain visibility changes for an image and does not adjust margins.
I'm currently not sure whether this issue is related to the specific version of a support library, I was building this screen at the same time that this library was released. Also, I don't see this issue on Marshmallow, only on Lollipop and below. I would appreciate any help on how to solve this issue.
<!-- a container for all views that should scroll --> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <!-- the first block of views - they need percents --> <android.support.percent.PercentRelativeLayout android:id="@+id/carHolder" android:layout_width="match_parent" android:layout_height="wrap_content"> <ImageView android:id="@+id/car" android:layout_width="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:src="@drawable/car" app:layout_heightPercenet="25%"/> <ImageView android:id="@+id/sliderBg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/car" android:layout_centerHorizontal="true" android:src="@drawable/slider_bg"/> </android.support.percent.PercentRelativeLayout> <!-- a middle block of views, they don't need percents --> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <android.support.v7.widget.RecyclerView android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout> <!-- another block of views, they need percents --> <android.support.percent.PercentRelativeLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <!-- some other views --> </android.support.percent.PercentRelativeLayout> </LinearLayout> UPDATE
I see this issue in support library 23.3.0 as well, and not only when I populate the RecyclerView, but each time the ScrollView exceeds the screen height.
2 Answers
Answers 1
Although this isn't an answer on how to solve the issue with PercentRelativeLayout, this is an example of how to use percentages in a layout, in case that is all you are looking for.
<!-- a container for all views that should scroll --> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <!-- the first block of views - they need percents --> <LinearLayout android:id="@+id/carHolder" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:weightSum="1"> <ImageView android:id="@+id/car" android:layout_width="wrap_content" android:layout_height="0dp" android:layout_weight="0.25" android:layout_gravity="center_horizontal" android:src="@drawable/car" /> <ImageView android:id="@+id/sliderBg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:src="@drawable/slider_bg"/> </LinearLayout> <!-- a middle block of views, they don't need percents --> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <android.support.v7.widget.RecyclerView android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout> <!-- another block of views, they need percents --> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:weightSum="1"> <!-- some other views --> </LinearLayout> </LinearLayout> Here's a nice explanation about it too!
Answers 2
It happens that aspectRatio parameter works fine here, and since I know the width of the view as well, I can get to the preferred height by using this parameter and percent based width.
I'll mark this answer as a temporal solution and accept any other answer that helps solving the issue the right way.
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