Develop Reference

How to configure an <include> layout in xml

I have included a layout with an EditText into my host-layout. The imeOptions of the EditText in the include-layout should be configurable from my host-layout. Therefore I added a variable and the hook in the include-layout.
My problem is that in the host-layout I want to set the actual flag as value like this
app:customImeOptions="#{actionNext}"
By doing so I get the error "Cannot find identifier 'actionNext'". The only thing that works is setting the integer value.
app:customImeOptions="#{0x00000006}"
The Include-Layout
<data>
...
<variable
name="customImeOptions"
type="Int"/>
</data>
<ConstraintLayout
...
...>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:imeOptions="#{customImeOptions}/>
</ConstraintLayout>
The Host Layout
<ConstraintLayout
...
...>
<include
layout="#layout/include_layout"
app:customImeOptions="#{0x00000006}" />

To set the flag in the host layout one must import the corresponding class in the host-layout. In this case add this import in the data section of the host-layout
<data>
<import type="android.view.inputmethod.EditorInfo" />
</data>
Now that the host-layout knows this class it is possible to set the flag instead of the int-value like this
<include
layout="#layout/include_layout"
app:customImeOptions="#{EditorInfo.IME_ACTION_NEXT}" />

How to hide button in landscape mode when using Databinding

I have a view that uses DataBinding to display data from a ViewModel. The view has a button that is hidden when the view is in landscape mode. At the moment this works by having two layoutfiles, but I would like to only have one as it's a nightmare to refactor. But how to go about this using DataBinding and BindingAdapters?
How do you enable the following bindingexpression for a given view?
android:visibility="#{isLandscapeMode ? View.INVISIBLE : View.VISIBLE}"
EDIT:
My extension property definition (ViewUtils.kt):
val View.isLandscapeMode: Boolean
get() = resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
And my layout:
<layout 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">
<data>
<import type="android.view.View"/>
<import type="com.example.base.views.ViewUtilsKt" />
<variable
name="isLandscapeMode "
type="java.lang.Boolean"/>
<variable
name="viewmodel"
type="com.example.ui.task.TaskViewModel" />
</data>
...
<ImageButton
...
android:visibility="#{isLandscapeMode ? View.INVISIBLE : View.VISIBLE}"
...
/>
This causes a compile error: Cause: not a valid name: isLandscapeMode

You have to check in your binding adapter which phone orientation is currently on. Here is another post where you can find answer to your question how to detect orientation of android device?
EDIT:
You need to detect orientation and save it as boolean value. Later you have to pass that variable to your adapter which in this case will be boolean.
<data>
<import type="android.view.View"/>
<variable
name="isLandscapeMode"
type="boolean"/>
</data>

For others if they need same behavior. There are two solutions.
First solution (create a BindingAdapter and use it on the UI element of your choice):
#BindingAdapter("bind:visibleInLandscapeMode")
fun View.setVisibleInLandscapeMode(visible: Boolean) {
Timber.d("setVisibleInLandscapeMode() returns ${resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE}")
visibility = if (visible && (resources.configuration.orientation != Configuration.ORIENTATION_LANDSCAPE)) VISIBLE else INVISIBLE
}
In your XML layout:
<layout 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"
xmlns:bind="http://schemas.android.com/apk/lib/com.example">
...
<ImageButton
...
bind:visibleInLandscapeMode="false"
...
/>
Second solution (create a bindingexpression that changes the visibility of the UI element):
<ImageButton
...
android:visibility="#{context.getResources.getConfiguration.orientation == Configuration.ORIENTATION_LANDSCAPE ? View.INVISIBLE : View.VISIBLE}"
...
/>
Remember the correct imports:
<layout 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">
<data>
<import type="android.view.View"/>
<import type="android.content.res.Resources" />
<import type="android.content.res.Configuration" />
...
</data>
...
Btw. be careful when using Databinding with AndroidAnnotation. See issue here and here.

Android: Pass different content from viewmodel to different include-tags

In my task app I want to use databinding for the task overview. I've grouped tasks in three categories: overdue, today and future.
My task_overview.xml defines the following viewmodel (which contains three arraylists with the different tasks)
<data>
<variable
name="viewModel"
type="de.taskapp.ui.taskOverview.viewmodel.TaskOverviewViewModel" />
</data>
A few steps later I include the layout for the three task lists with the include tag like this
<include layout="#layout/layout_task_list"
android:id="#+id/overdued_tasks_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/headline"/>
<include layout="#layout/layout_task_list"
android:id="#+id/todays_tasks_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/overdued_tasks_list"/>
<include layout="#layout/layout_task_list"
android:id="#+id/future_tasks_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/todays_tasks_list"/>
It would be awesome if I could do something like this to pass the different lists from the viewmodel to the layout_task_list.xml via the include tag
app:entries="#{viewModel.todaysTasks}" // for the todays task list case
My layout_task_list.xml looks like this
<layout 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">
<data>
<variable
name="tasks"
type="android.databinding.ObservableArrayList" />
</data>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.AppCompatTextView
android:id="#+id/subheading"
android:layout_width="match_parent"
android:layout_height="wrap_content"
style="#style/SubheadlineWithBackground"
tools:text="Heute"/>
<android.support.v7.widget.RecyclerView
android:id="#+id/task_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/spacing_large"
android:layout_marginRight="#dimen/spacing_large"
android:nestedScrollingEnabled="false"
app:entries="#{tasks}" //recyclerviewbinding is already there
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
app:layout_constraintTop_toBottomOf="#id/subheading"/>
</android.support.constraint.ConstraintLayout>
As you may suggest...the code is not working. This error message is shown
data binding error ****msg:Cannot find the setter for attribute 'app:entries' with parameter type android.databinding.ObservableList<de.taskapp.data.entity.Task> on de.molske.einfachmachen.databinding.LayoutTaskListBinding. file:/Users/app/src/main/res/layout/layout_task_overview.xml loc:38:40 - 38:60 ****\ data binding error ****
Okay yeah its telling me that he cannot find the setter for app:entries...but isn't there a "beautiful" way to pass the three lists to the three include-layouts? I don't like the idea to copy and paste the same layout three times just to be able to pass the different lists.
Thanks in advance.
(ps.: I know that there is the possibility to solve this by java / android code but I would like to know if there is a databind way to do this ;-)

Okay, classic me. After a few more googling I found the solution. Adding the next lines to the data-section of the included file everything works fine!
<import type="java.util.List"/>
<import type="de.molske.einfachmachen.data.entity.Task"/>
<variable name="title" type="java.lang.String"/>
<variable
name="tasks"
type="List<Task>"/>
It seems that it's important to define the exact type of the tasks variable. Because its type is a genereic < and > instead of < and > for defining the type.

Cannot set string array for spinner using Android data binding

I have a spinner now and I want to load the data to the spinner with data binding feature. I tried to find the way to declare the string array in the XML(https://developer.android.com/topic/libraries/data-binding/index.html#expression_language) but no satisfied result is found.
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:apps="http://schemas.android.com/apk/res-auto">
<data>
<import type="android.util.SparseArray"/>
<variable
name="statuslist"
type="SparseArray<String>"/>
</data>
...
<android.support.v7.widget.AppCompatSpinner
android:id="#+id/spn_status"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignStart="#+id/spinner1"
android:layout_below="#+id/btn2"
android:entries="#{statuslist}"
apps:adapter="#{statusAdapter}"/>
</layout>
When it is build, the following error is shown.
Error:Execution failed for task ':app:dataBindingProcessLayoutsDebug'.
org.xml.sax.SAXParseException; systemId: file:/C:/Users/../app/build/intermediates/res/merged/debug/layout/testdialog.xml; lineNumber: 24; columnNumber: 30; The value of attribute "type" associated with an element type "null" must not contain the '<' character.
However, there is something confused.
When I tried to use SparseArray as shown on website. I found a "Cannot resolve sysmbol" in Android Studio XML Editor.
I do not know is it the correct way to setup the array value for the spinner since there is no official instructions for the spinner data bindingin the website.

have you import the SparseArray ?
try this :
<data><import type="android.util.SparseArray"/></data>

This is a very simple way to setup a spinner with a string-array from your resource's array.xml
<Spinner
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:entries="#array/spinner_array_items"/>
The spinner_array_items should contain a list of items to be found in the spinner dropdown.

Change SparseArray<String> to SparseArray<String>.

Well my implementation logic is based on your's but used ArrayList instead SparseArray.
XML:
<data>
<import type="java.util.ArrayList" />
<variable
name="cities"
type="ArrayList<String>"
/>
</data>
<!-- Location -->
<Spinner
android:id="#+id/dd_city"
android:entries="#{cities}"
style="#style/dropdown"
/>
Now, we just need to bind our ArrayList to cities variable through Binding Class.
At least data will be bind : ).
TC.

Visibility not working in data binding android

I am using the latest data binding in android using android studio 2.1.
using the visibility tag as describe in the below code getting an error as
java.lang.RuntimeException: Found data binding errors.
/ data binding error ****msg:Identifiers must have user defined types from the XML file. View is missing it
file:D:\HP\HealthPortal_Android\Code\app\src\main\res\layout\cardview_image_twotextview.xml
loc:68:90 - 68:93
\ data binding error
<TextView
android:id="#+id/card_sub_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/card_title"
android:layout_marginLeft="#dimen/carview_margin"
android:layout_toRightOf="#+id/card_image"
android:text="#{toolsAndTrackersCards.subtitle}"
android:textColor="#color/black"
android:textSize="20sp"
android:visibility="#{toolsAndTrackersCards.subtitle.equals(#string/Empty_String) ? View.VISIBLE : View.GONE}"
/>
Done some google not abel to find the solution. The #string/Empty_String is define as empty string "" in string.xml file. where I am doing wrong.
Android data binding, Radio Button not updating

Add this to your cardview_image_twotextview.xml:
<data>
<import type="android.view.View" />
<!--your variables-->
</data>

To hide a view if the string is empty, use the below expression in data binding
<data>
<import type="android.view.View"/>
<variable
name="item"
type="com.test.model.Item" />
</data>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#{item.title}"
android:visibility='#{item.title.equals("") ? View.GONE : View.VISIBLE}'/>
NOTE: need to use outer single quote string in order to use double quote to
represent the empty string
If you want to check for null and empty, use the below code :
<data>
<import type="android.view.View"/>
<import type="android.text.TextUtils"/>
<variable
name="item"
type="com.test.model.Item" />
</data>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#{item.title}"
android:visibility="#{TextUtils.isEmpty(item.title) ? View.GONE : View.VISIBLE}"/>

Zero or more import elements may be used inside the data element.
These allow easy reference to classes inside your layout file, just
like in Java.
you need to import View class inorder to use its properties.
<data>
<import type="android.view.View"/>
</data>
you can also refer official DataBinding guideline.