Develop Reference

Android pass include layout ressource id as variable

I'm using databinding with a layout that include another, and I would like to pass the ressource id of layout to include as a parameter, so the included layout can be changed programmatically.
#layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="layoutResId"
type="int" />
<import type="android.view.View"/>
</data>
<android.widget.LinearLayout
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="wrap_content">
<include layout="#{layoutResId}"/>
</android.widget.LinearLayout>
</layout>
But i have this issue:
layout attribute must start with "#layout/."

You can add the id in the container layout where your include tag resides. For example:
<FrameLayout>
...
<include layout="#layout/main"
android:id="#+id/main_container" --> add id here
/>
</FrameLayout>

Why Isn't My Bound Data Showing Up in Android XML?

I have a custom layout that I want to reuse in several places, so I want to be able to pass a title to it, since that's the only value that will actually change. I know I can do that by binding data, but I can't get the data to render.
In my activity.main I have:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.r.e.MainActivity">
<include
layout="#layout/switch_preference_custom_title"
app:passedTitle="#{#string/hello_world}" />
</RelativeLayout>
</layout>
I have defined my custom layout as follows:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" >
<data>
<variable
name="passedTitle"
type="String"/>
</data>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#{passedTitle}" />
</RelativeLayout>
</layout>
I also added
dataBinding {
enabled = true
}
in my build.gradle. My project compiles and runs fine, and the layout does render (I can tell by giving it a background), but the text is an empty string.

It looks like one final linking piece was missing. Instead of having
setContentView(R.layout.activity_main);
in MainActivity, one needs to declare
DataBindingUtil.setContentView(this, R.layout.activity_main);
This connects the Data Binding library with the root layout, without which none of your data bindings will actually render.

Toggle visibility of custom view in XML via Databinding

I have a fragment layout fragment_config.xml, which cointains the following:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:bind="http://schemas.android.com/tools">
<data>
<import type="android.view.View"/>
<variable name="viewModel" type ="...GlobalConfigViewModel"/>
</data>
...
<ToggleButton
android:id="#+id/btnShowAdvanced"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textOff="Show Advanced"
android:textOn="Hide Advanced"
android:checked="#={viewModel.advancedShown}"/>
<com.minh.minh.pumpnotifier.global.configuration.AdvancedBox
android:id="#+id/advancedBox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="#{viewModel.advancedShown ? View.VISIBLE : View.GONE}"
app:viewModel = "#{viewModel}"/>
...
</layout>
What is supposed to happen is that the visibility of Advanced Box toggles with the "checked"-state of the toggle button. I already confirmed that the two-way-databinding in the toggle-button sets the boolean "advancedShown" in the viewModel correctly. The "setVisibility"-method however is never called in the AdvancedBox-class (which extends LinearLayout).
Something else I tried is to set the visibility binding in the root element of the advanced_box.xml, since it also has a reference to the viewModel:
<?xml version="1.0" encoding="utf-8"?>
<layout>
<data>
<import type="android.view.View"/>
<variable
name="viewModel"
type="...GlobalConfigViewModel" />
</data>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/advancedSettings"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="#{viewModel.advancedShown ? View.VISIBLE : View.GONE}"
android:orientation="vertical">
Both methods do not work out though. My question is why it does not work and what would be the correct way to use databinding in this case?

Your viewModel.advancedShown should be ObservableField or marked with #Bindable annotation (in the second variant you need manually invoke notifyPropertyChanged(BR.advancedShown) on your GlobalConfigViewModel to trigger changes). You can find more information in official docs

Android - Make new view attribute and pass to its children in XML compound view component - data binding in layout

Full answer:
1. Enable data binding in app/build.gradle:
dataBinding {
enabled true
}
2. Use DataBindingUtil to set content view
java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DataBindingUtil.setContentView(this, R.layout.activity_engineering_mode_main);
}
3. Child item layout
You will see that I define 2 new attributes
values/bools.xml
<variable
name="textTitle"
type="String" />
<variable
name="buttonVisibility"
type="boolean" />
With textTitle, you can use any string from resource by #string/string_name
With buttonVisibility, you have to define bool resource type, and use #bool/bool_name
layout/item_engineering_list_row.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<import type="android.view.View" />
<variable
name="textTitle"
type="String" />
<variable
name="buttonVisibility"
type="boolean" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="#dimen/engineer_actionbar_height"
android:background="#color/engineer_background_color"
android:orientation="horizontal">
<TextView
android:id="#+id/engineer_txtName"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginLeft="#dimen/engineer_text_margin"
android:layout_weight="1"
android:gravity="center_vertical"
android:text="#{textTitle}"
android:textColor="#color/engineer_text_color"
android:textSize="#dimen/engineer_title_font_size" />
<Button
android:id="#+id/engineer_btnNext"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginRight="#dimen/engineer_text_margin"
android:text="BACK"
android:visibility="#{buttonVisibility ? View.VISIBLE : View.GONE, default=gone}" />
</LinearLayout>
</layout>
4. Boolean resource file
<?xml version="1.0" encoding="utf-8"?>
<resources>
<bool name="item_button_visibility_default">false</bool>
<bool name="item_button_visibility_on">true</bool>
<bool name="item_button_visibility_off">false</bool>
</resources>
5. Parent layout, which includes some children and passes value to new attributes
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
android:id="#+id/includedLayout0"
layout="#layout/item_engineering_list_row"
app:buttonVisibility="#{#bool/item_button_visibility_on}"
app:textTitle="#{#string/app_name}" />
<include
android:id="#+id/includedLayout1"
layout="#layout/item_engineering_list_row"
app:buttonVisibility="#{#bool/item_button_visibility_default}"
app:textTitle="#{#string/app_name}" />
</LinearLayout>
</layout>
Original Question:
I am new to android and I've been working with QML in QT for a time.
I wonder how I can make a layout more easier by applying params in XML in compound view components.
I have a custom layout item in xml and want to pass some attributes from a parent to its children, and I also want to initialize parent's attribute with new values to customize its children too.
My concept is as below:
item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
!!!! how to declare a new attribute here !!!
| like this:
| textTitle="New Title" // default value for child
| buttonVisibility="visible" // default value for child
">
<TextView
android:id="#+id/engineer_txtTitle"
android:text= textTitle <--- use parent's />
<Button
android:id="#+id/engineer_btnBack"
android:visibility= buttonVisibility <== use parent's />
</LinearLayout>
CLICK HERE TO SEE IMAGE: base Item
main.xml
<LinearLayout>
<include
android:id="#+id/item1"
layout="#layout/item"
textTitle= "FIRST"
// buttonVisibility not set here, use default as visible
/>
<include
android:id="#+id/item2"
layout="#layout/item"
textTitle= "SECOND"
buttonVisibility = "gone" // dont show button
/>
</LinearLayout>
CLICK HERE TO SEE IMAGE: apply with param

You can use Data Binding of Architecture component. Here is an sample of your requirement.
Recently I answered a question related to this.
Clean answer
This example shows pass value to <include.
I have a common view layout_common.xml, I want to pass String to included layout. I will create a variable of type String. Refer that String to your TextView. I created passedText for example.
<?xml version="1.0" encoding="utf-8"?>
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
>
<data>
// declare fields
<variable
name="passedText"
type="String"/>
</data>
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#{passedText}"/> //set field to your view.
</layout>
Now you can pass passedText field to your <include tag.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<include
android:id="#+id/includedLayout"
layout="#layout/layout_common"
app:passedText="#{#string/app_name}" // here we pass any String
/>
</LinearLayout>
</layout>
Note that both layouts (parent & included) should be binding layout, i.e. wrapped with <layout> and </layout> tags

Thanks #Khemraj to show the keyword "Data Binding" in Android :)
I have found the answer for me. It includes Khemraj's answer and some small code added to values resource.
I posted it in my question for others to find it easily.

Breaking down complex XML layouts using the same data-binding context

Context
XML layouts in Android can get complicated. Hence, it is a good practice to break them down into conceptually independent modules. Consider the following example:
Main layout:
<layout>
<data>
<variable name="someVar" type="some.custom.Type"/>
</data>
<SomeLayout
...
android:someAttribute="#{someVar.someProperty}" />
<include layout="#layout/some_other_layout />
</layout>
and some_other_layout.xml:
<SomeOtherLayout
...
android:someOtherAttribute="#{someVar.someOtherProperty}" />
Problem
Is it possible to use the same data-binding context (whatever is inside <data>) in two separated layouts (like in the given example)?
Doing this naively results in java.lang.IllegalStateException.

From the Data Binding Library documentation:
Variables may be passed into an included layout's binding from the containing layout by using the application namespace and the variable name in an attribute:
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto">
<data>
<variable name="user" type="com.example.User"/>
</data>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include layout="#layout/name"
bind:user="#{user}"/>
<include layout="#layout/contact"
bind:user="#{user}"/>
</LinearLayout>
</layout>