I was wondering if someone found some clever solution to reuse components (multiple views) when working with MVVM.
By component I mean a set of views that end up being reused in an app.
For instance, an empty state formed of an ImageView and a TextView, and let's also add some sort of ClickListener for the text, for the sake of the example.
Now, what I want to do is to reuse this view in multiple .xml files BUT providing different values for the text, the image, and bind the listener to action in the Fragment's ViewModel.
What I've been doing is create a CustomEmptyState that would extend a LinearLayout or some kind of Layout and add Custom Attributes to it.
So, in the end, I would use my custom view like this:
<com.whatever.customViews.CutomEmptyState
app:image="#drawable/someImage"
app:text="#string/empty_text"
app:onTextClicked="#{viewModel.onEmptyStateClicked()}" />
My question would be, is there a different approach to this? A better one? What I dislike about this is writing the custom attributes with <declare-styleable> and all because then I have to keep track of 3 files:
The .xml layout of the base view
The .java/.kt of the view with the boilerplate code to handle the attributes
The <declare-styleable> with all the attributes
Is there any way to combine 2 and 3?
Say, you have to display some text value which you are sure will be databinded.
Then, if you databind the value, then there is a way, but not an elegant way.
declare a variable in the custom view like: private var status = ""
then write a setter function:
fun setStatus(status: String) {
this.status = status
//refresh your views based on value or set this to the text view
}
and then databind like this:
app:status="#{viewModel.status}"
so that you don't need to declare the stylable anymore
<com.whatever.customViews.CutomEmptyState
app:image="#drawable/someImage"
app:text="#string/empty_text"
app:onTextClicked="#{viewModel::onEmptyStateClicked}" />
public void onEmptyStateClicked(View view){
your code
}
I've spent about 6 hours on this so far, and been hitting nothing but roadblocks. The general premise is that there is some row in a ListView (whether it's generated by the adapter, or added as a header view) that contains an EditText widget and a Button. All I want to do is be able to use the jogball/arrows, to navigate the selector to individual items like normal, but when I get to a particular row -- even if I have to explicitly identify the row -- that has a focusable child, I want that child to take focus instead of indicating the position with the selector.
I've tried many possibilities, and have so far had no luck.
layout:
<ListView
android:id="#android:id/list"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
/>
Header view:
EditText view = new EditText(this);
listView.addHeaderView(view, null, true);
Assuming there are other items in the adapter, using the arrow keys will move the selection up/down in the list, as expected; but when getting to the header row, it is also displayed with the selector, and no way to focus into the EditText using the jogball. Note: tapping on the EditText will focus it at that point, however that relies on a touchscreen, which should not be a requirement.
ListView apparently has two modes in this regard:
1. setItemsCanFocus(true): selector is never displayed, but the EditText can get focus when using the arrows. Focus search algorithm is hard to predict, and no visual feedback (on any rows: having focusable children or not) on which item is selected, both of which can give the user an unexpected experience.
2. setItemsCanFocus(false): selector is always drawn in non-touch-mode, and EditText can never get focus -- even if you tap on it.
To make matters worse, calling editTextView.requestFocus() returns true, but in fact does not give the EditText focus.
What I'm envisioning is basically a hybrid of 1 & 2, where rather than the list setting if all items are focusable or not, I want to set focusability for a single item in the list, so that the selector seamlessly transitions from selecting the entire row for non-focusable items, and traversing the focus tree for items that contain focusable children.
Any takers?
This helped me.
In your manifest :
<activity android:name= ".yourActivity" android:windowSoftInputMode="adjustPan"/>
Sorry, answered my own question. It may not be the most correct or most elegant solution, but it works for me, and gives a pretty solid user experience. I looked into the code for ListView to see why the two behaviors are so different, and came across this from ListView.java:
public void setItemsCanFocus(boolean itemsCanFocus) {
mItemsCanFocus = itemsCanFocus;
if (!itemsCanFocus) {
setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
}
}
So, when calling setItemsCanFocus(false), it's also setting descendant focusability such that no child can get focus. This explains why I couldn't just toggle mItemsCanFocus in the ListView's OnItemSelectedListener -- because the ListView was then blocking focus to all children.
What I have now:
<ListView
android:id="#android:id/list"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:descendantFocusability="beforeDescendants"
/>
I use beforeDescendants because the selector will only be drawn when the ListView itself (not a child) has focus, so the default behavior needs to be that the ListView takes focus first and draws selectors.
Then in the OnItemSelectedListener, since I know which header view I want to override the selector (would take more work to dynamically determine if any given position contains a focusable view), I can change descendant focusability, and set focus on the EditText. And when I navigate out of that header, change it back it again.
public void onItemSelected(AdapterView<?> listView, View view, int position, long id)
{
if (position == 1)
{
// listView.setItemsCanFocus(true);
// Use afterDescendants, because I don't want the ListView to steal focus
listView.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
myEditText.requestFocus();
}
else
{
if (!listView.isFocused())
{
// listView.setItemsCanFocus(false);
// Use beforeDescendants so that the EditText doesn't re-take focus
listView.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
listView.requestFocus();
}
}
}
public void onNothingSelected(AdapterView<?> listView)
{
// This happens when you start scrolling, so we need to prevent it from staying
// in the afterDescendants mode if the EditText was focused
listView.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
}
Note the commented-out setItemsCanFocus calls. With those calls, I got the correct behavior, but setItemsCanFocus(false) caused focus to jump from the EditText, to another widget outside of the ListView, back to the ListView and displayed the selector on the next selected item, and that jumping focus was distracting. Removing the ItemsCanFocus change, and just toggling descendant focusability got me the desired behavior. All items draw the selector as normal, but when getting to the row with the EditText, it focused on the text field instead. Then when continuing out of that EditText, it started drawing the selector again.
My task was to implement ListView which expands when clicked. The additional space shows EditText where you can input some text. App should be functional on 2.2+ (up to 4.2.2 at time of writing this)
I tried numerous solutions from this post and others I could find; tested them on 2.2 up to 4.2.2 devices.
None of solutions was satisfactionary on all devices 2.2+, each solution presented with different problems.
I wanted to share my final solution :
set listview to android:descendantFocusability="afterDescendants"
set listview to setItemsCanFocus(true);
set your activity to android:windowSoftInputMode="adjustResize"
Many people suggest adjustPan but adjustResize gives much better ux imho, just test this in your case. With adjustPan you will get bottom listitems obscured for instance. Docs suggest that ("This is generally less desirable than resizing"). Also on 4.0.4 after user starts typing on soft keyboard the screen pans to the top.
on 4.2.2 with adjustResize there are some problems with EditText focus. The solution is to apply rjrjr solution from this thread. It looks scarry but it is not. And it works. Just try it.
Additional 5. Due to adapter being refreshed (because of view resize) when EditText gains focus on pre HoneyComb versions I found an issue with reversed views:
getting View for ListView item / reverse order on 2.2; works on 4.0.3
If you are doing some animations you might want to change behaviour to adjustPan for pre-honeycomb versions so that resize doesnt fire and adapter doesn't refresh the views. You just need to add something like this
if(android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.HONEYCOMB)
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
All this gives acceptable ux on 2.2 - 4.2.2 devices.
Hope it will save people some time as it took me at least several hours to come to this conclusion.
This saved my life--->
set this line
ListView.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
Then in your manifest in activity tag type this-->
<activity android:windowSoftInputMode="adjustPan">
Your usual intent
We're trying this on a short list that does not do any view recycling. So far so good.
XML:
<RitalinLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ListView
android:id="#+id/cart_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbarStyle="outsideOverlay"
/>
</RitalinLayout>
Java:
/**
* It helps you keep focused.
*
* For use as a parent of {#link android.widget.ListView}s that need to use EditText
* children for inline editing.
*/
public class RitalinLayout extends FrameLayout {
View sticky;
public RitalinLayout(Context context, AttributeSet attrs) {
super(context, attrs);
ViewTreeObserver vto = getViewTreeObserver();
vto.addOnGlobalFocusChangeListener(new ViewTreeObserver.OnGlobalFocusChangeListener() {
#Override public void onGlobalFocusChanged(View oldFocus, View newFocus) {
if (newFocus == null) return;
View baby = getChildAt(0);
if (newFocus != baby) {
ViewParent parent = newFocus.getParent();
while (parent != null && parent != parent.getParent()) {
if (parent == baby) {
sticky = newFocus;
break;
}
parent = parent.getParent();
}
}
}
});
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override public void onGlobalLayout() {
if (sticky != null) {
sticky.requestFocus();
}
}
});
}
}
this post was matching exactly my keywords. I have a ListView header with a search EditText and a search Button.
In order to give focus to the EditText after loosing the initial focus the only HACK that i found is:
searchText.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// LOTS OF HACKS TO MAKE THIS WORK.. UFF...
searchButton.requestFocusFromTouch();
searchText.requestFocus();
}
});
Lost lots of hours and it's not a real fix. Hope it helps someone tough.
If the list is dynamic and contains focusable widgets, then the right option is to use RecyclerView instead of ListView IMO.
The workarounds that set adjustPan, FOCUS_AFTER_DESCENDANTS, or manually remember focused position, are indeed just workarounds. They have corner cases (scrolling + soft keyboard issues, caret changing position in EditText). They don't change the fact that ListView creates/destroys views en masse during notifyDataSetChanged.
With RecyclerView, you notify about individual inserts, updates, and deletes. The focused view is not being recreated so no issues with form controls losing focus. As an added bonus, RecyclerView animates the list item insertions and removals.
Here's an example from official docs on how to get started with RecyclerView: Developer guide - Create a List with RecyclerView
some times when you use android:windowSoftInputMode="stateAlwaysHidden"in manifest activity or xml, that time it will lose keyboard focus. So first check for that property in your xml and manifest,if it is there just remove it. After add these option to manifest file in side activity android:windowSoftInputMode="adjustPan"and add this property to listview in xml android:descendantFocusability="beforeDescendants"
Another simple solution is to define your onClickListener, in the getView(..) method, of your ListAdapter.
public View getView(final int position, View convertView, ViewGroup parent){
//initialise your view
...
View row = context.getLayoutInflater().inflate(R.layout.list_item, null);
...
//define your listener on inner items
//define your global listener
row.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
doSomethingWithViewAndPosition(v,position);
}
});
return row;
That way your row are clickable, and your inner view too :)
The most important part is to get the focus working for the list cell.
Especially for list on Google TV this is essential:
setItemsCanFocus method of the list view does the trick:
...
mPuzzleList = (ListView) mGameprogressView.findViewById(R.id.gameprogress_puzzlelist);
mPuzzleList.setItemsCanFocus(true);
mPuzzleList.setAdapter(new PuzzleListAdapter(ctx,PuzzleGenerator.getPuzzles(ctx, getResources(), version_lite)));
...
My list cell xml starts like follows:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/puzzleDetailFrame"
android:focusable="true"
android:nextFocusLeft="#+id/gameprogress_lessDetails"
android:nextFocusRight="#+id/gameprogress_reset"
...
nextFocusLeft/Right are also important for D-Pad navigation.
For more details check out the great other answers.
I just found another solution. I believe it's more a hack than a solution but it works on android 2.3.7 and android 4.3 (I've even tested that good old D-pad)
init your webview as usual and add this: (thanks Michael Bierman)
listView.setItemsCanFocus(true);
During the getView call:
editText.setOnFocusChangeListener(
new OnFocusChangeListener(View view,boolean hasFocus){
view.post(new Runnable() {
#Override
public void run() {
view.requestFocus();
view.requestFocusFromTouch();
}
});
Just try this
android:windowSoftInputMode="adjustNothing"
in the
activity
section of your manifest.
Yes, it adjusts nothings, which means the editText will stay where it is when IME is opening. But that's just an little inconvenience that still completely solves the problem of losing focus.
In my case, there is 14 input edit text in the list view. The problem I was facing, when the keyboard open, edit text focus lost, scroll the layout, and as soon as focused view not visible to the user keyboard down. It was not good for the user experience. I can't use windowSoftInputMethod="adjustPan". So after so much searching, I found a link that inflates custom layout and sets data on view as an adapter by using LinearLayout and scrollView and work well for my case.
I want to change the background color of a customView when it's pressed and slightly "remove" this background color when the view losses the "pressed-state". However, I googled this question and found a solution using a StateListDrawable. I've tried this within my customView (which is added to a ListView programmatically), but just the "normal color" was set to my view. When I touched the view nothing happens. What's going wrong?
the selector xml-file:
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:state_pressed="true"
android:drawable="#color/bckgr" />
<item
android:drawable="#color/transparent" />
</selector>
within the constructor of my custom view:
this.setBackgroundResource(R.drawable.list_item_bckgr);
you have to apply your background to the View the Adapter fills up (the view your getView implementation is returning) not to the ListView self
Try setting android:descendantFocusability to true on the ListView.
Hey Are you making the view focussable and clickable, use in the constructor:
setClickable(true);
setFocusable(true);
May be your view isn't getting focus.
You need to set the OnTouchListener to handle touch events. When the view is touched, change the background, and when the view is 'untouched', change the background back to the original.
To set the listener, call the View.setOnTouchListener() function of your custom view with the OnTouchListener you create to handle these events.
Here is the reference to OnTouchListener:
http://developer.android.com/reference/android/view/View.OnTouchListener.html
I imagine that you have an override method to the OnTouch() method, what I would do is create an instance variable (class var) that would hold the image that you want to have as a background, and set it in your OnTouch() method. Then, Override your OnDraw() method which would give you a reference to the canvas, and use the canvas.DrawBitmap() to draw your background.
This answer shows you more details on how to draw the bitmap
Setting background image in a custom view
As mentioned in topic, I have some Views, e.g. a TableRow with always the same background used as topic, or a special TableRow containing a TextView with some special styles/properties. These Views are set dynamically, so it's problematic to use a XML for this. As I read it's not possible to set styles programmatically too. So what's the best way to solve that?
Possibility 1:
I use and instance derived Views, like this:
public class TopicTableRow extends TableRow {
public TopicTableRow(Context context) {
super(context);
setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
setBackgroundColor(Color.parseColor("#777777"));
setClickable(false);
}
}
Possibility 2:
I could create a valid xml template with a special layout I never use in the application, containing the needed Views which have already all assigned styles. Afterward I access the needed Views by R.id....
But this method seems to be very dilettante to me.
I don't think that those 2 possibilities are the "real" Android way to do this, so how is this usually done?
If you want to set specific styles for groups of elements, you can use the themes and styles concepts in android.
You can read up on them here: http://developer.android.com/guide/topics/ui/themes.html
It is not possible though to change the style attribute of a view programatically.
Therefore the android way is probably to create the Views you need in XML and use a LayoutInflater to get create an 'java' version of the xml view. This allows you to reuse the component and fill it with apropriate data for as many rows as you would like.
Button view = (Button) LayoutInflater.from(this).inflate(R.layout.textViewFromWeb, null);
I hope this will be of use to you!
I understand how to create a custom Android control, and I believe I understand how to pull attributes for it from the Xml layout. I don't know, however, how to get any children elements from it.
Here's a visual example of what I'm trying to accomplish:
public class Menu extends LinearLayout
{
// Custom Code
}
public class MenuItem extends Button
{
// Custom Code
}
<!-- Layout -->
<?xml version="1.0" encoding="utf-8"?>
<Menu>
<MenuItem/>
<MenuItem/>
</Menu>
When my Menu is created, how do I get references to the two MenuItems?
You should use an android:id to do that. If you will not know how many childs you will have:
LinearLayout extends ViewGroup, so you can use getChildAt() and getChildCount() to get those views.
for accesing any control (custom or system ) an id is a must. by specifying an id you give it a unique identity. Using this id you can get a reference to that control.