I've created a custom linear layout within android studio. This layout gets inflated into another vertical layout programatically. Now I want to map a button inside this layout, which can delete the whole object. Here is my layout:
And as you can see the button "DELETE HERE" should remove the 3 items, time, weekday and the button itself.
This is my class and here
class AlarmCard #JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyle: Int = 0,
defStyleRes: Int = 0,
) : LinearLayout(context, attrs, defStyle, defStyleRes) {
init {
LayoutInflater.from(context)
.inflate(R.layout.alarmcard, this, true)
btnDelete.setOnClickListener(){
**/* Call destructor or remove view !?!*/**
}
}
}
which get added to the linear layout with:
val monday = AlarmCard(this)
alarmCards.addView(monday)
The problem is for me how can I delete the object with a button? I tried using alarmCards.removeView(this) within btnDelete.setOnClickListener() but It crashes. :(
Thank you!!
Try this:
btnDelete.setOnClickListener {
(getParent() as? ViewGroup)?.removeView(this#AlarmCard)
}
Let's say the layout XML for my activity has a view like this. The XML below has a hard-coded value for the attribute, but I want to pass value from activity when setting the content view.
<myView
android:id = "#+id/myView
....
app:myAttriute = "someMode"/>
The view reads that value in the constructor like the following and sets the initial mode.
constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
{
val inflater = context?.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
inflater.inflate(R.layout.myView, this);
var arr = context.obtainStyledAttributes(attrs, R.styleable.myView);
var mode = arr.getString(R.styleable.myAttribute);
Is it possible to set that attribute in the activity so that the value can be used in the view's constructor? It may sound weird, it causes some problems to change the mode after the view's constructor like this
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val myView = findView...
myView.myAttribute = "someMode";
If possible, I wish I could pass the attribute to its constructor, somehow.
super.onCreate(savedInstanceState)
//takes the view's ID and attribute name/value to be used while
//setting the content view (passed to myView's constructor)
hypotheticalMethod(R.id.myView, "myAttriute", "someMode");
setContentView(R.layout.activity_main)
As we have our App on Android O, there's a new feature introduced there, where it auto-suggest Home and Work location as per image below.
What is this called? Is there a way to disable it from our Edit Text showing it?
Apparently in Android-Oreo, there's this new feature call AUTOFILL
https://developer.android.com/guide/topics/text/autofill.html, where By default, the view uses the IMPORTANT_FOR_AUTOFILL_AUTO mode, which lets Android use its heuristics to determine if the view is important for autofill
Hence for field that is not intended to have that filled, just add the below to your view.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
setImportantForAutofill(IMPORTANT_FOR_AUTOFILL_NO);
}
Update: Found another approach to disable AUTOFILL
Use android:importantForAutofill="no" in the XML
https://developer.android.com/guide/topics/text/testautofill.html#trigger_autofill_in_your_app
Accepted answer is not a solution, it doesn't work for all cases, to Disable the Autofill completely on a particular View you should extend it and override getAutofillType() method:
class TextInputEditTextNoAutofill : TextInputEditText {
constructor(context: Context) : super(context)
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
#RequiresApi(Build.VERSION_CODES.O)
override fun getAutofillType(): Int {
return View.AUTOFILL_TYPE_NONE
}
}
This is Kotlin version, but you can get the point. Showcase repo:
https://github.com/BukT0p/AutofillBug
I'm trying to make a custom ProgressBar the way I did custom layouts a lot before. This time I'm having issues.
I can achieve the desired look with just this xml:
<ProgressBar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:indeterminateOnly="false"
android:progressDrawable="#drawable/progress_bar" />
The ultimate goal, however, would be doing some of the customization in the custom class so the xml shrinks to this:
<se.my.viktklubb.app.progressbar.HorizontalProgressBar
android:id="#+id/planProgressBar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
Here is the custom class:
class HorizontalProgressBar : ProgressBar {
constructor(context: Context) : super(context) {
initialSetup()
}
constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
initialSetup()
}
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
initialSetup()
}
fun initialSetup() {
max = 100
isIndeterminate = false
progressDrawable = context.getDrawable(R.drawable.progress_bar)
}
}
Second constructor gets fired but the bar isn't styled. It actually appears as indeterminate spinning progress and none of these setup gets applied eventually - feels like those are overriden later by something else.
What's wrong here?
DISCLAIMER:
This is a very simple example. I'm perfectly aware I could go for styles or a simple xml implementation but I just use this simple case only to demonstrate the issue.
According to the bullet 5 of this article, you may need to modify initialSetup:
fun initialSetup() {
max = 100
isIndeterminate = false
progressDrawable = context.getDrawable(R.drawable.progress_bar)
invalidate()
requestLayout()
}
If it doesn't change anything, try calling initialSetup later, on onResume of activity/fragment for example. If this work, the problem is maybe linked to the complexity of initialization/lifecycle of android components.
I have tried many solutions found in google by the keywords: multiple constructors, scala, inheritance, subclasses.
None seems to work for this occasion. ImageView has three constructors:
ImageView(context)
ImageView(context,attribute set)
ImageView(context,attribute set, style)
In scala you can only extend one of them. And the solution of using the more complete constructor (ImageView(context,attribute set, style)) and passing default values does not work either because the constructor ImageView(context) does something completely different than the other two constructors.
Some solutions of using a trait or a companion object does not seem to work because the CustomView must be a class! I mean I am not the only one who uses this class (so I could write the scala code any way I wanted) there is also the android-sdk who uses this class and yes it must be a class.
target is to have a CustomView which extends ImageView and all of these work:
new CustomView(context)
new CustomView(context,attribute set)
new CustomView(context,attribute set, style)
Please let me know if you need any further clarification on this tricky matter!
According to Martin Odersky (the creator of Scala), that is not possible.
In http://scala-programming-language.1934581.n4.nabble.com/scala-calling-different-super-constructors-td1994456.html:
"is there a way to call different super-constructors within different
class-constructors - or does all have to go up to the main-constructor and only
one super-constructor is supported?
No, it has to go through the main constructor. That's one detail where
Scala is more restrictive than Java."
I think your best approach is to implement your views in Java.
It sounds like you may just be better off writing the subclass in Java. Otherwise, if your assumption about the SDK using the three argument constructor is correct, then you could use a trait and a class with a companion object. The SDK would use the three argument constructor of CustomView which also implements a trait containing any additional behavior you need:
trait TCustomView {
// additional behavior here
}
final class CustomView(context: Context, attributes: AttributeSet, style: Int)
extends ImageView(context, attributes, style) with TCustomView
In the application code, you could use the one, two or three argument version in this way:
object CustomView {
def apply(c: Context, a: AttributeSet, s: Int) =
new ImageView(c, a, s) with TCustomView
def apply(context: Context, attributes: AttributeSet) =
new ImageView(context, attributes) with TCustomView
def apply(context: Context) = new ImageView(context) with TCustomView
}
CustomView(context)
CustomView(context, attributes)
CustomView(context, attributes, style)
Seems like a lot of work. Depending on your goals, you might be able to add additional behavior with implicits:
implicit def imageViewToCustomView(view: ImageView) = new {
def foo = ...
}
This question lead me to several design considerations which I would like to share with you.
My first consideration is that if a Java class has been correctly designed the availability of multiple constructors should be a sign of the fact that some class properties might have default value.
Scala provides default values as a language feature, so that you do not have to bother about providing multiple constructors at all, you can simply provide default value for some arguments of your constructor. This approach leads to a much cleaner API than three different constructors which produce this kind of behaviour as you are making clear why you do not need to specify all the parameters.
My second consideration is that this is not always applicable in case you are extending classes of a third-party library. However:
if you are extending a class of an open source library and the class is correctly designed, you can simply investigate the default values of the constructor argument
if you are extending a class which is not correctly designed (i.e. where overloaded constructors are not an API to default some parameters) or where you have no access to the source, you can replace inheritance with composition and provide an implicit conversion.
class CustomView(c: Context, a: Option[AttributeSet]=None, s: Option[Int]=None){
private val underlyingView:ImageView = if(a.isDefined)
if (s.isDefined)
new ImageView(c,a.get,s.get)
else
new ImageView(c,a.get)
else
new ImageView(c)
}
object CustomView {
implicit def asImageView(customView:CustomView):ImageView = customView.underlyingView
}
According to the Android View documentation View(Context) is used when constructed from code and View(Context, AttributeSet) and View(Context, AttributeSet, int) (and since API level 21 View(Context, AttributeSet, int, int)) are used when the View is inflated from XML.
The XML constructor all just call the same constructor, the one with the most arguments which is the only one with any real implementation, so we can use default arguments in Scala. The "code constructor" on the other hand may have another implementation, so it is better to actually call in from Scala as well.
The following implementation may be a solution:
private trait MyViewTrait extends View {
// implementation
}
class MyView(context: Context, attrs: AttributeSet, defStyle: Int = 0)
extends View(context, attrs, defStyle) with MyViewTrait {}
object MyView {
def apply(context: Context) = new View(context) with MyViewTrait
}
The "code constructor" may then be used like:
var myView = MyView(context)
(not a real constructor).
And the other once like:
var myView2 = new MyView(context, attrs)
var myView3 = new MyView(context, attrs, defStyle)
which is the way the SDK expects them.
Analogously for API level 21 and higher the class can be defined as:
class MyView(context: Context, attrs: AttributeSet, defStyle: Int = 0, defStyleRes: Int = 0)
extends View(context, attrs, defStyle, defStyleRes) with MyViewTrait {}
and the forth constructor can be used like:
var myView4 = new MyView(context, attrs, defStyle, defStyleRes)
Update:
It gets a bit more complicated if you try to call a protected method in View, like setMeasuredDimension(int, int) from the trait. Java protected methods cannot be called from traits. A workaround is to implement an accessor in the class and object implementations:
private trait MyViewTrait extends View {
protected def setMeasuredDimensionAccessor(w: Int, h: Int): Unit
def callingSetMeasuredDimensionAccessor(): Unit = {
setMeasuredDimensionAccessor(1, 2)
}
}
class MyView(context: Context, attrs: AttributeSet, defStyle: Int = 0)
extends View(context, attrs, defStyle) with MyViewTrait {
override protected def setMeasuredDimensionAccessor(w: Int, h: Int) =
setMeasuredDimension(w, h)
}
object MyView {
def apply(context: Context) = new View(context) with MyViewTrait {
override protected def setMeasuredDimensionAccessor(w: Int, h: Int) =
setMeasuredDimension(w, h)
}
}