I am trying to set android:textAppearance with use of DataBinding , but it is not allowing me to use ?android:attr/textAppearanceLarge with ternary operator.
android:textAppearance="#{position==1 ? ?android:attr/textAppearanceLarge : ?android:attr/textAppearanceMedium}"
It is showing me compile time error <expr> expected, got '?'.
Does there any other way to use this with DataBinding?
You cannot use it directly, however here's trick I use in such cases. Create own styles using textAppearanceLarge and textAppearanceMedium as parents and then set these styles instead:
First create Foo style:
<style name="Foo" parent="TextAppearance.AppCompat.Large">
... [whatever you need to set or override ] ...
</style>
and do the same for for FooMedium. Then edit your layout file as shown below. Note you must import project's R class in <data> block first:
<data>
<import type="<your-package-id>.R"
</data>
Finally apply the appearance as you formerly wanted:
android:textAppearance="#{ position==1 ? R.style.Foo : R.style.FooMedium }"
You can use android.R.attr package instead of the ?android:attr
<?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>
<import type="android.R.attr"/>
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="hello world"
android:textAppearance='#{age==1 ? android.R.attr.textAppearanceLarge : android.R.attr.textAppearanceMedium}'
tools:textAppearance="?android:textAppearanceLarge"
/>
</LinearLayout>
</layout>
Looks like DataBinding treats android:textAppearance in some special way (at least on Android Studio 3.2.1).
For example the following expression according to this should be fine, but it is not.
The following expression is being accepted by the compiler but it is doing nothing:
android:textAppearance="#{R.style.MyStyleTest}"
I have tried several options and only vanilla way worked for me:
android:textAppearance="#style/MyStyleTest"
As a Solution
I would suggest to use #BindingAdapter and perform all the logic there.
For example if you would like to work with references to attributes (which looks like: ?attr/...) use the following approach:
layout.xml
<TextView
...
bind:textAppearanceAttr="#{position==1 ? android.R.attr.textAppearanceLarge: android.R.attr.textAppearanceMedium}"
/>
sources.kt
#BindingAdapter(value = ["textAppearanceAttr"])
fun textAppearanceAttr(textView: TextView, #AttrRes attrRef: Int?) {
attrRef?.also {
val attrs = textView.context.obtainStyledAttributes(intArrayOf(attrRef))
val styleRes = attrs.getResourceId(0, -1)
attrs.recycle()
if (styleRes != -1) {
TextViewCompat.setTextAppearance(textView, styleRes)
}
}
}
or in case of style resource ids (#style/...):
layout.xml
bind:textAppearanceStyle="#{position==1 ? R.style.MyStyleTest1: R.style.MyStyleTest2}"
sources.kt
#BindingAdapter(value = ["textAppearanceStyle"])
fun textAppearanceStyle(textView: TextView, #StyleRes style: Int?) {
style?.also { TextViewCompat.setTextAppearance(textView, it) }
}
You should use textStyle instead of textAppearance,
Try to use code give below:
android:textStyle="#{position==1 ? #style/TextAppearance.Material.Large :#style/TextAppearance.Material.Medium}"
For more reference use below image
Related
I want to set text using binding adapter.Here is the MyBindingAdapter.kt
#BindingAdapter("android:setTitle")
fun setTitle(textView : TextView,text: String){
textView.text = text
}
in activity_table.xml I used setTitle like this
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_column="1"
android:layout_weight="1"
android:gravity="center"
android:setTitle="Hello word"/>
and I getting below error in compile time
You need to change from #BindingAdapter("android:setTitle") to #BindingAdapter("setTitle") in your MyBindingAdapter.kt.
Also you need to change in xml file from android:setTitle="Hello word" to setTitle="Hello word"
It should work now!
Android studio will not consider #BindingAdapter("android:setTitle") while binding it, you need to write only #BindingAdapter("setTitle") to execute it perfectly, otherwise it will give that binding error while compile time.
First make sure you have to enclose you layout within the <layout> tag
<layout
xmlns:android="http://schemas.android.com/apk/res/android">
..... </layout>
and #BindingAdapter("android:setTitle") change as #BindingAdapter("title")
it should work.
I want my view visibility to be dependent on condition behaviour so I am using ObservableField and with databinding trying to change view visibility but getting issue like "Identifiers must have user defined types from the XML file. InputType is missing it"
Code:
Kotlin File
var showView: ObservableField<Boolean>? = ObservableField(false)
//API call response
showView.set(true)
Layout File:
<TextView
android:id="#+id/textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="#{viewModel.showView ? View.VISIBLE : View.GONE}"/>
How to apply databinding with Observablefield of type boolean? I have used it for string text also and it's working but not working with boolean conditional statement.
I am not sure if that's the case here, but this error message is usually displayed when you reference a type in your binding expressions that hasn't been declared in the <data> section of your layout. The same way you declare the View type as an import, you should declare the type InputType.
<data>
<!-- Maybe an import for InputType is missing here? -->
<import type="android.view.View" />
<variable
name="viewModel"
type="com.yourpackage.YourViewModel"/>
</data>
I have created a custom bindingAdapter in android and when i pass in the color i want the color to change, this is actually for a test im working on just to make sure it works. Here is the code:
here is my view Model for the data binding:
public class User {
public ObservableInt visible;
public User(int visible) {
this.visible=new ObservableInt(visible);
}
#BindingAdapter({"app:bindColor"}) //notice the bindColor custom attribute
public static void setTextColor(TextView view,String color) {
if("green".equals(color))
view.setTextColor(Color.parseColor("#63f421"));
}
}
Now in my xml file which is binded to this model im expected to pass in a color so that the setTextColor method can use it:
<?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">
<data class="MainActivityBinder">
<variable name="user" type="com.example.android.floatingactionbuttonbasic.User"/>
</data>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/tv_one"
android:text="my first textview"/>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/tv_two"
android:text="my second textview"
android:visibility="#{user.visible}"
app:bindColor="#{'green'}" //see im passing in the green string here
android:textColor="#android:color/holo_green_dark"/>
</LinearLayout>
</layout>
I am getting the error at runtime time of:
Error:(27, 65) error: package com.example.android.floatingactionbuttonbasic.databinding does not exist
Warning:Application namespace for attribute app:bindColor will be ignored.
Error:(24, 33) Identifiers must have user defined types from the XML file. een is missing it
Error:Execution failed for task ':Application:compileDebugJavaWithJavac'.
> java.lang.RuntimeException: Found data binding errors.
if i take out the bindingAdapter stuff it works perfectly with the other databinding stuff. Its just this custom binding thats not working. My project is titled floatingactionbuttonbasic btw.
I was able to get this to work. The issue was how i was passing in the string. It should have the `` around it.
app:bindColor="#{`green`}"
you can also do this :
app:bindColor='#{"green"}'
But what seems to not be allowed is this notation:
app:bindColor="#{'green'}"
i wrote a blog about it to help others if interested.
I currently have a bool.xml file in android which looks like this:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<bool name="showAds">true</bool>
</resources>
Now i have a layout.xml file which uses databinding. I want to show or hide the visilibity of a adView based on a the boolean showAds defined above. So far i have this:
<com.google.android.gms.ads.AdView
android:id="#+id/adView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="#{#bool/showAds ? View.Visible:View:gone}"
ads:adSize="BANNER"
ads:adUnitId="ca-app-pub-1234567/34343">
but it does not compile. how can i get the boolean to decide if the ad should show or not ?The syntax is wrong.
Correct the syntax of condition View.Visible:View:gone
android:visibility="#{#bool/showAds ? View.VISIBLE:View.GONE}"
and you need to import View in the data section:
<data>
<import type="android.view.View"/>
</data>
If you don't like adding the View import (in each layout where needed), you can simply define a #BindingConversion annotated method:
#BindingConversion
public static int convertBooleanToVisibility(boolean visible) {
return visible ? View.VISIBLE : View.GONE;
}
The annotated method can be in whatever Java file in your project.
Then you can simply use
android:visibility="#{#bool/showAds}"
I am trying out the new Android Databinding Library and I wanted to set the background color of ToolBar using a binding. By default the color should be colorPrimary (from the theme).
Before I was using DataBinding, my toolBar looked like
<android.support.v7.widget.Toolbar
android:id="#+id/mainToolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
/>
After adding a binding, I wanted to set its background to colorPrimary if no color is bound - I'm using ternary operator for this (as mentioned in the guide) - but it causes an error, as theme attributes also have a "?" operator before their names. The compiler thinks I'm starting a new ternary operation.
<data>
<variable name="toolBarBackgroundColor" type="int"/>
</data>
...
<android.support.v7.widget.Toolbar
android:id="#+id/mainToolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#{toolBarBackgroundColor!=0? toolBarBackgroundColor: ?attr/colorPrimary }"
/>
So is there a way I can access theme attributes inside a binding operation? Thanks!
Edit
I know I can get the colorPrimary attribute programmatically and bind it through java code. But I'm just wondering if there's an Xml-based solution for this or not.
The answer is a bit late, but maybe it helps someone.
For accessing theme attributes in data binding, you can use this:
(imagine that clickable is Boolean variable)
android:background="#{clickable ? android.R.attr.selectableItemBackground : android.R.color.transparent}"
No additional binding adapters or another things needed.
Finding a way using data-binding? Here is what I have done with test. First, create a custom binding adapter method:
#BindingAdapter({"app:customPrimaryBackground"})
public static void setCustomPrimaryBackground(View v, int resId) {
TypedValue typedValue = new TypedValue();
Context context = v.getContext();
if (resId == 0) {
context.getTheme().resolveAttribute(R.attr.colorPrimary, typedValue, true);
v.setBackgroundResource(typedValue.resourceId);
} else {
// Check the given resource ID is a color or drawable
context.getResources().getValue(resId, typedValue, true);
Drawable drawable;
if (typedValue.type >= TypedValue.TYPE_FIRST_COLOR_INT && typedValue.type <= TypedValue.TYPE_LAST_COLOR_INT) {
// It's a color
drawable = new ColorDrawable(typedValue.data);
} else {
drawable = ContextCompat.getDrawable(context, resId);
}
v.setBackground(drawable);
}
}
Second, your binding xml layout:
<data>
<variable name="toolBarBackgroundColor" type="int"/>
</data>
...
<android.support.v7.widget.Toolbar
android:id="#+id/mainToolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:customPrimaryBackground="#{toolBarBackgroundColor}"
/>
If the question is still actual for someone, this is the example how to use custom and android attributes
app:textColorAttr="#{error ? com.example.R.attr.textColorError : android.R.attr.textColor}", where textColorAttr implemented using BindingAdapter, error is Boolean and com.example is your package name
I found another solution without custom attributes and binding adapters. The idea is to place an invisible View with android:background and android:foreground attributes in XML markup and use these attributes in a binding expression.
<data>
<variable name="toolBarBackgroundColor" type="int"/>
</data>
...
<android.support.v7.widget.Toolbar
android:id="#+id/mainToolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#{toolBarBackgroundColor != 0 ? helperView.getBackground() : helperView.getForeground() }"
/>
<View
android:id="#+id/helperView"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#{toolBarBackgroundColor}"
android:foreground="?attr/colorPrimary"
android:visibility="gone"
/>