Develop Reference

Saving state of UI in Android

I'm making a to-do list app and after user presses the button I create a new GridLayout(and all the data about time and name of the task inside of it) and add it into my RelativeLayout. How do I save those GridLayouts in UI so after the activity is destroyed and launched again those layouts are there.
After pressing the button I trigger the Create Activity method
public void CreateActivity(String name,int hours, int minutes,int i)
{
RelativeLayout.LayoutParams relparams= new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT,RelativeLayout.LayoutParams.WRAP_CONTENT);
relparams.addRule(RelativeLayout.BELOW,i);
relparams.setMargins(0,50,0,100);
Glayouts.add(new GridLayout(this));
Glayouts.get(i+1).setBackgroundColor(Color.GRAY);
Glayouts.get(i+1).setMinimumWidth(relative.getWidth());
Glayouts.get(i+1).setId(i+1);
Glayouts.get(i+1).setPadding(10,0,0,0);
GridLayout.LayoutParams namee = new GridLayout.LayoutParams();
namee.columnSpec = GridLayout.spec(0);
namee.rowSpec = GridLayout.spec(0);
namee.setGravity(Gravity.LEFT);
final TextView Actname = new TextView(this);
Actname.setText(name);
GridLayout.LayoutParams checkbox = new GridLayout.LayoutParams();
checkbox.columnSpec = GridLayout.spec(1);
checkbox.rowSpec = GridLayout.spec(0);
checkbox.setGravity(Gravity.RIGHT);
CheckBox check = new CheckBox(this);
// ADDING TO LAYOUT
Glayouts.get(i+1).addView(Actname,namee);
Glayouts.get(i+1).addView(check,checkbox);
relative.addView(Glayouts.get(i+1),relparams);

Theoretically when you extends View, then you can also override onSaveInstanceState and onRestoreInstanceState methods, where you must provide your own SavedState class that typically extends BaseSavedState. You can find info on that here
In your case, your layout is dynamic, therefore this doesn't really work. To tell you the truth, your layout probably shouldn't be constructed this way, you should be rendering the grid using a RecyclerView based on a "model" that describes this layout, render the items of the grid via the RecyclerView.Adapter, and you should persist either the "model", or the data you use to construct this model along with the user-inputted state so that you can re-construct the model that will be rendered via your RecyclerView.
You can read more about RecyclerView here.
You can read more about data persistence here.
You can read about using onSaveInstanceState to save data in Activities/Fragments across config change and process death (but not finishing then restarting the app) here.

You can’t. The best way to save state is to use some persistence mechanism, for example database (I’d recommend Room as it is officially supported by Google).
After clicking a button, you should put all the needed information (name, hours, minutes) in the database and when Activity is created, you can read all persisted data and - basing on it - create all needed layouts again.
Another option is storing data in SharedPreferences - it is much easier to setup, so you can also start with this solution. Please note, I'm suggesting it as a first step in the world of persistency in Android, not as a preferred solution for storing data.

Android - Place fragment over ImageView PROGRAMMATICALLY (NO XML)

I have to add a fragment over an Imageview, but my ImageView goes on top and covers the other views. All this is done in a RelativeLayout.
things must be done dynamically (no xml). I want that my activity has an image, which can be set DYNAMICALLY, and my fragment (added dynamically) should have transparent background, and if this is not true, i can set it to transparent at run time.
This is the code to create the image:
ImageView img=new ImageView(this);
img.setImageResource(imgID);
img.setScaleType(ImageView.ScaleType.CENTER_CROP);
((ViewGroup)findViewById(android.R.id.content)).getRootView()).addView(img);
As you can see, the image works as background, i'm using a ImageView for its scaleType.
Is there a way to do so?

SOLUTION
solved, i added the image to the wrong container.
The function below, however, has been pretty useful. It has been taken from an other answer, and lets a view to get on the back of all the others.
public static void sendViewToBack(View child) {
final ViewGroup parent = (ViewGroup)child.getParent();
if (parent!=null) {
parent.removeView(child);
parent.addView(child, 0);
}
}

Android AccessibilityDelegate force reading of ViewGroup not children

I'm using a viewpager which is made up of some number of relative layout siblings which are quite complex.
If I click on the relative layout, it will highlight the entire page and read the title and a few textviews one after the other as expected.
If I scroll the viewpager I'd like talkback to read the next page in the same way it reads the first if I click. Secondly, if I scroll to the second, third, etc. pages and click on those layouts, talkback will read as expected.
I am trying to achieve the click behavior after the scroll event has completed.
Here is what I have for the accessibilityDelegate.
viewPager.setAccessibilityDelegate(new AccessibilityDelegate () {
#Override
public boolean onRequestSendAccessibilityEvent(ViewGroup host, View child, AccessibilityEvent event) {
if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
View page = viewPager.getCurrentPageView();
performAccessibilityAction(page, AccessibilityNodeInfo.ACTION_CLICK, Bundle.EMPTY);
}
return super.onRequestSendAccessibilityEvent(host, child, event);
}
});
I've verified that 'page' is the RelativeLayout parent that I think it is. I've also confirmed that the onRequestSendAccessibilityEvent is being fired, but it doesn't read the contents of its children. Am I missing something?
Updated
I've also tried using
viewpager.getCurrentPageView().sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
The above worked for another example when I needed to force talkback to reread a single item but does not have any affect if I try it on the page.
Thanks

Some background -- When you tap on the relative layout, TalkBack generates speech based on the layout's contents. On ICS, this is triggered by a HOVER_ENTER event. On Jelly Bean, it's triggered by an ACCESSIBILITY_FOCUS event. These events are sent automatically by the framework and should, generally speaking, never be sent manually from an app. The same goes for FOCUS events, except in the special case of custom views (see Accessibility talk from Google I/O 2013 for more details).
So, back on topic.
You can control the speech for SCROLLED events by populating the outgoing event with the text you want read. The down side of this is that you'll need to manually generate the text you want read, and it's very likely that this text will differ from what TalkBack will read if the user touches the layout.
viewPager.setAccessibilityDelegate(new AccessibilityDelegate () {
#Override
public void onPopulateAccessibilityEvent(View host, AccessibilityEvent event) {
super.onPopulateAccessibilityEvent(host, event);
if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
event.setContentDescription(/** your text */);
}
}
});
Another option is to do nothing and let the user explore the view on their own. This is the preferred interaction model for Android accessibility.
Edit: Video URL is broken, Changed.

This issue was reported on google check
where ViewPager does not set AccessibilityEvent parameters properly
when scrolling.
But after releas of Android Support Library, revision 23.2.1 (March 2016) This issue has been resolved.
update Support Library to Android Support Library to 23.2.1

I had the same issue before. And now I add android:focusable="true" to the ViewGroup, the TalkBalk will read the ViewGroup, instead of its children

Android: Adding accessibility to a custom view

I'm attempting to implement accessibility on a few custom views for an Android app.
I've condensed what is done in the Google Authenticator app with no luck:
public class CardView extends RelativeLayout {
// ...
#Override
public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
event.setClassName(this.getClass().getName());
event.setPackageName(this.getContext().getPackageName());
event.getText().add("Card Test");
return true;
}
}
All TalkBack reports back is "Double-tap to select" when it's inside a ListView or ViewPager.
Does ViewPager override accessibility events?
What do I need to do in order to have TalkBack say "Card Test" inside ViewPagers and ListViews like I expect it to?

For current versions of Android, you need to set the content description of the view.
myView.setContentDescription("Card Test");

ListView and associated classes expect you to use the onItemSelectedListener instead of assigning an onClickListener to each View (and rightfully so).

If incorporating alanv's suggestion, try to convince android system to read out the content description
by either
If(accessibilityModeIsEnabled())//custom method that checks context.getSystemService(Context.ACCESSIBILITY_SERVICE).isEnabled()
myView.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_HOVER_ENTER);
or AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED.
or requestFocus
Above should done when myView is visible. May be during onMesasure when width and height are both positive
If list view is still unable to do so, then try doing the above tricks on the first element of list view. Accessibility in Android varies devices to device and not one strategy fits all

Java swing, test state of a button?

I am trying to write a method that will toggle a button from being disabled to being enabled and back using a simple if statement.
I would assume that it would be something like
if (buttonDisable.setEnabled(true) == true){
//do stuff
}
But I haven't had much luck finding my answer via google.

Don't test the display of the model, test the model.
if (buttonDisable.getModel().isEnabled()) {
// do stuff
}
That way if you change the model, you avoid a level of dispatch (view --- updates ---> model --- updates ---> view(s))
A better solution is to make your model changes independent of the view. This way you don't get tied into requiring a specific view to be present to make the model change.
ButtonModel toggle = new ButtonModel();
...
JButton button = new JButton(toggle);
...
// this is clear that we are manipulating the model, not the view
// as new views are added / removed, this toggle will continue to work
toggle.setEnabled(!toggle.isEnabled());

Why not just toggle the state in one shot:
buttonDisable.setEnabled(!buttonDisable.isEnabled())