I want to implement a custom view within some Fragments, and this view doesn't have any dependency on activity, this way I can share it as a common UI component to others.
But I have a problem when trying to use FragmentManager to manage those Fragments inside the custom view, how can I get a FragmentManager instance? Generally, we can get it from Activity, but in my case, what should I do would be more reasonable?
If your custom view is inflated by a fragment you have access to getParentFragmentManager there is more info here
But I have a problem when trying to use FragmentManager to manage those Fragments inside the custom view, how can I get a FragmentManager instance? Generally, we can get it from Activity, but in my case, what should I do would be more reasonable?
The best way to do it is to define an interface in the view to describe what events it has, then the fragment that hosts this view will implement this interface and actually handle it.
fun View.onClick(clickListener: (View) -> Unit) {
setOnClickListener(clickListener)
}
class MyView: FrameLayout {
constructor(context: Context) : super(context)
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr)
interface Listener {
fun onSomeEvent(someData: SomeData)
}
var listener: Listener? = null
override fun onFinishInflate() {
super.onFinishInflate()
val binding = MyViewBinding.bind(this)
with(binding) {
someButton.onClick {
listener?.onSomeEvent(someData)
}
}
}
}
And then
class MyFragment: Fragment(R.layout.my_fragment), MyView.Listener {
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
val binding = MyFragmentBinding.bind(view)
with(binding) {
myView.listener = this#MyFragment
}
}
}
Related
I have a custom view that is initially not visible. However this is determined with a binding adapter. My question as simple as it sounds, how do I write a test to check if the view is visible when the binding adapter method is called?
For example, this is my custom view:
class MyView #JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : LinearLayout(context, attrs, defStyleAttr) {
fun setVisibile(visible: Boolean) {
this.visibility = if (visible) VISIBLE else GONE
}
}
And this is the binding adapter method :
#BindingAdapter(“visible)
#JvmStatic
fun setVisible(myView: MyView, someObject: SomeObject?) {
// Some checking on someObject
// ....
myView.setVisible(someObject.someCriteria())
}
How to save scroll state of scrollview properly.In my code, I'm using :
scroll_x = scrollView.getScrollX();
scroll_y = scrollView.getScrollY();
when activity pause,i'm stored x and y as you can see here, and when activity start, i'm scroll scrollView to x and y.
But crux is (main problem) is, scrollview not scrollview to x and y properly, it scroll up or down a little bit automatically. How to fix it?
You can manage the instance state by using this class:
class SaveScrollNestedScrollViewer : NestedScrollView {
constructor(context: Context) : super(context)
constructor(context: Context, attributes: AttributeSet) : super(context, attributes)
constructor(context: Context, attributes: AttributeSet, defStyleAttr: Int) : super(context, attributes, defStyleAttr)
public override fun onSaveInstanceState(): Parcelable? {
return super.onSaveInstanceState()
}
public override fun onRestoreInstanceState(state: Parcelable?) {
super.onRestoreInstanceState(state)
}
}
use on your xml:
<yourClassNamePlace.SaveScrollNestedScrollViewer
android:id="#+id/my_scroll_viewer"
android:layout_width="match_parent"
android:layout_height="match_parent">
</yourClassNamePlace.SaveScrollNestedScrollViewer>
and then use in activity like this:
class MyActivity : AppCompatActivity() {
companion object {
var myScrollViewerInstanceState: Parcelable? = null
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.my_activity)
if (myScrollViewerInstanceState != null) {
my_scroll_viewer.onRestoreInstanceState(myScrollViewerInstanceState)
}
}
public override fun onPause() {
super.onPause()
myScrollViewerInstanceState = my_scroll_viewer.onSaveInstanceState()
}
}
I'm trying to use 2-way databinding on a custom view that contains a SeekBar. The layout is rather simple, but I need to reuse it across the project, hence wrapping it into a custom view/component
<androidx.constraintlayout.widget.ConstraintLayout ... />
<TextView .../>
<TextView .../>
<SeekBar
android:id="#+id/ds_seekbar"
android:layout....
android:max="9"
android:min="0"
android:progress="0"
</androidx.constraintlayout.widget.ConstraintLayout>
The backing code looks like so (reduced)
CustomView #JvmOverloads constructor(
context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr), View.OnClickListener {
init {
LayoutInflater.from(context).inflate(R.layout.custom_view, this, true)
ds_description.setOnClickListener(this)
}
override fun onClick(view: View) {
//onClick implementation
}
}
I can do the binding in the ViewModel for the layout where this custom view is going to be used, with a BindingAdapter there with custom attribute (ex. app:seekbar), but the custom view would be used multiple times and I'd prefer to have the a lot of the logic that is required into the view and have a "lighter" handling in the ViewModel.
I read Android 2-Way DataBinding With Custom View and Custom Attr and a bunch of other articles which seem to be a little different but oon the same topic, however no matter how I wrote the getter and setters I always run into the kapt exception that it cannot find the getter/setter.
Either I'm not annotating properly the methods or they have wrong signatures.
Ideally I want to have something like:
CustomView #JvmOverloads constructor(
context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr), View.OnClickListener, SeekBar.OnProgressChangedListener {
... ds_seekbar.setOnProgressChangedListener(this)
And then in the main layout have the app:progress (or even better if someone can show how it's done android:progress) on the custom view for binding when passing my object.
Okay after more and more headscratching, here's what I've come with, that seems to work. Whether this is the proper way or how performant/reliable is - I'm not sure
#InverseBindingMethods(InverseBindingMethod(type = CustomView::class, attribute = "progress", event = "progressAttrChanged"))
CustomView #JvmOverloads constructor(...
private var progress = 0
private var mInverseBindingListener: InverseBindingListener? = null
cv_seekbar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
override fun onProgressChanged(seekBar: SeekBar, i: Int, b: Boolean) {
progress = i + 1
if (mInverseBindingListener != null) {
mInverseBindingListener!!.onChange()
cv_indicator.text = progress.toString()
}
}...
})
fun getProgress(): Int {
return progress
}
fun setProgress(p: Int) {
if (progress != p) {
progress = p
}
}
fun setProgressAttrChanged(inverseBindingListener: InverseBindingListener?) {
if (inverseBindingListener != null) {
mInverseBindingListener = inverseBindingListener
}
}
Then the XML is
<com.xxx.CustomView
android:id="#+id/xxx"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:progress="#={viewModel.dataobject.value}"
....
/>
I'm newbie in Kotiln and this code is simple class which I'm using on Android. In this class I want to make simple listener to detect clicks on item inside of a class such as activity, fragment or adapter. My problem is that I can define this listener for circularProgressView widget.
class DownloadProgressView : RelativeLayout {
var progressListener: ((downloading: Boolean) -> Unit)? = null
private var downloading = false
constructor(context: Context?) : super(context) {
init()
}
constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {
init()
}
constructor(context: Context?, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
init()
}
private fun init() {
LayoutInflater.from(context).inflate(R.layout.download_progress_layout, this)
circularProgressView.setOnClickListener {
downloading = !downloading
setProgressViews(downloading)
progressListener?.invoke(downloading)
//if listener!=null then onItemClicked.onClick();
}
}
}
How can I know if user clicked on circularProgressView inside activity?
I'm trying to implement this interface and use it inside Kotlin:
public interface OnItemClickListener {
void onClick(int position);
}
For init progreessListener use following code
var listener: () -> Unit = {}
For call onClick use : listener()
For implement your interface use following code :
var onItemClickInterface : () -> Unit = {
//TODO
}
If we are building a custom View, for example, something like this:
class FrameLayoutNormal: FrameLayout{
constructor(context: Context) : this(context, null)
constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
textView{
lparams(...)
}
}
we can't define lparams, because the compiler doesn't know who the parent is. If we wrap the textView inside a FrameLayout it works, and you scan specify a layout parameter. But in a custom view, the parent is itself. So how can we make the children be aware of that so we can use the extension?
Is there any way to get it working, besides extending from: _FrameLayout ?`
An old question, but since it is common ...
Applying the answer from https://github.com/Kotlin/anko/issues/267
I think you might want something like this:
class FrameLayoutNormal: AnkoComponent<Context> {
override fun createView(ui: AnkoContext<Context>): View {
return with(ui) {
frameLayout {
textView("Hello") {
}.lparams()
}
}
}
}
inline fun ViewManager.frameLayoutNormal(theme: Int = 0) = frameLayoutNormal(theme) {}
inline fun ViewManager.frameLayoutNormal(theme: Int = 0, init: View.(frameLayoutNormal: FrameLayoutNormal) -> Unit): View {
val fln = FrameLayoutNormal()
return ankoView({ fln.createView(AnkoContext.create(it))}, theme, {init(fln)})
}
This allows the component to be used in the ANKO DSL. One downside to this approach is that the custom component is a View, not a ViewGroup, and thus can not have additional children added outside of its definition. It is challenging/laborious to make a custom component which is a ViewGroup that can be used in ANKO DSL (if I understand correctly).