I am using a UICollectionView in C# Xamarin ios and sometimes all of the cells will disappear from the screen. This happens normally on a scroll and I have to re-invoke the view that my UICollection View is on.
I can't show my exact code as this is a project that I am working on but the initialization basics look a little like this:
Bounds screenBounds = screen.Bounds
UICollectionViewFlowLayout layout = new UICollectionViewFlowLayout();
UICollectionView collectionView = new UICollectionView(layout, bounds)
I initialize a few other things like source and register cell and also add separation and border styles.
I have been also getting an error about a view not being in the hierarchy don't know if this has anything to do with it.
I do return the collectionView at the end and will add this returned value to my template which has a scroll view in which I add the UICollectionView to.
May I also mention I don't use any of the StoryBoard and am using a DuqueReusable cell in my collection view source.
I have been stuck on this for ages so thank you in advance for anyone who can give me any sort of tips or answers to this question.
Insure you make any changes to ItemsSource or to cells data on UI thread only, otherwise you might obtains an uncatchanble async crash and you'll end up with an empty view.
Device.BeginInvokeOnMainThread(() => {
// do your stuff
});
I searched lot on internet to find a solution for my problem but I haven't found a answer. I hope someone can help me.
I have a Android application where I made a fragment with 3 tabs. Every tab had a different layout and in every layout there is a listview with different id. The problem is that, when i click on item of listview, only the item of the first tab take focus and background was set to green. In the other tabs the item is selected but focus don't change the background item color.
I had clear the focus on the first tab if was selected but this don't resolve the problem.
this is the code that I implementer on tab
listView.setAdapter(adapter);
listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
listView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View view,
int pos, long arg3) {
view.setSelected(true);
selectedBusiness = businessList.get(pos);
buttonModify.setEnabled(true);
}
});
Any idea?
Thank Max
I found the solution.
The error in my case was made from
ArrayAdapter adapter = new ArrayAdapter(getActivity(), R.layout.my_business_item);
I don't know why but the problem was the layout. In the other two tabs, I used the adapter with another layout android.R.layout.simple_list_item_1. With this layout the focus dosen't work. With my simple layout it works.
Color newColor = new Color(197,222,90);
JButton newButton;
newButton = new JButton(icon);
newButton.setBacgroundColor(newColor);
When it is pressed it changes color. How can I keep it from changing color? I have multiple buttons, so if there is solution in one or two rows please help me, and keep in mind that I'm beginner, writing some huge classes won't help me, because I have multiple buttons with different names to be affected with this.
EDIT: Solution in one line is:
UIManager.put("Button.select", newColor);
But it changes all button colors but I need another to have different a color.
EDIT2: After some research I figured out there isn't an easy solution (but it should be). How I see it I have 2 solutions, 1. is to break buttons to separate classes and set UIManager for them, and second is to make custom buttons. It is just too much work for button.
I've found nothing that can change that particular behavior on a normal JButton. The problem being, that whatever you write in your actionlistener for the button, will occur AFTER you've let go of the mousebutton, and not "while clicking".
There are workarounds, however.
My preferred choice is, to remove all graphics from the button, and then add your own images to the button's regular and pressed states. You could take a screenshot of your GUI, cut out the button, and set that image to be both states.
JButton myButton = new JButton();
// Sets button x, y, width, height. Make the size match the image.
myButton.setBounds(5, 30, 100, 30);
// Remove border-graphics.
myButton.setBorder(null);
// Remove default graphics from the button
myButton.setContentAreaFilled(false);
// Remove the focus-indicating dotted square when focused (optional)
myButton.setFocusPainted(false);
// Here, myImage is a simple BufferedImage object.
// You can set one like this, provided you have an "images" package,
// next to your main class (ex: com.somecompany.someprogram.images),
// that contains an image:
BufferedImage myImage = ImageIO.read(getClass().getResource("images/myImage.png"));
// Then we simply apply our image to both states for the button, and we're done.
myButton.setIcon(new ImageIcon(myImage));
myButton.setPressedIcon(new ImageIcon(myImage));
Obviously there are many ways to retain and load an image, but since that's not the issue here, I'll leave additional methods out of it.
There's no need to go through it all countless times, though. It should be pretty easy to write your own custom implementation of the JButton class, in which a custom constructor takes a single parameter, being the BufferedImage, and then the constructor sets it up accordingly (changes the icons). Then all you have to do when you create a new JButton, is to use your own class, and pass it an image:
JButton btn = new MyCustomJButton(myImage);
You could also easily get along with very few images. All you need is a HashMap which holds all the images, with a String as a key. Imagine you need 4 OK-buttons. You make a single image of a button with the text "OK" written on it. Then you put that image into the HashMap, like so:
myMap.put("OK", myImage);
Then you could do this when creating a button, over and over again if you'd like more:
JButton btn = new MyCustomJButton(myMap.get("OK"));
Alternatively:
Another way of achieving this, which is pretty elaborate, but probably considered "the right way", is to use ButtonUI, as presented in this answer to another post.
If the OP is referring to the temporary change of background colour on a button with an icon at the moment the mouse is pressed, the following statement does the trick:
button.setContentAreaFilled(false);
"If you wish to have a transparent button, such as an icon only button, for example, then you should set this to false."
This took me a long time to figure out. It seems to be a little known technique, perhaps since its name gives little clue as to its effect.
With only first lane we can still see that it is clicked. You need to combine those two:
button1.setContentAreaFilled(false);
button1.setEnabled(false);
and if you don't wanna in grey color you put another button under him.
panelname.add(button1,+5,+5); \\(first not clicable, not visible button, notice +5)
panelname.add(button2,-5,-5); \(-5,-5 means it is 5 points under panel)
I am developing the following screen
The fourboxes next to each other are buttons. On clicking of the buttons I am changing the adapter of the listview.
Since the content above the listview took up lot of space I made the whole thing as an header and added it via code.
myPollsList = (ListView) findViewById(R.id.listArea);
myPollsList.addHeaderView(getLayoutInflater().inflate(R.layout.profile_listview_header, null));
Now I want to show some view when the list is empty. But if I do that then the header also goes away.
I am using this in a Activity and not a ListActivity. Any suggestions or workarounds for showing the header even when the list is empty ?
EDIT: Refer to my earlier question here ListView not getting space to show content on smaller screens . This is where someone suggested me to solve the problem by putting it as a header
I found a simple solution for this problem. If there's no elements for list and you are not adding the adapter, just add this:
mListView.setAdapter(null);
and the header will appear. It's easier than adding empty / fake item to the list.
So this is how I solved it. I had a custom adapter which was connected to the listview. When it found that it had zero items to display. It would add a fake empty view as an item to the list.
maybe you will like this Android addHeaderView disappears when no items in ListView
override/subclass your adapter to return false from isEmpty()
Don't use top layouts of button as header for list view.
So to adjust UI without using list header use weights.
Give parent Linear layout weight sum as 4 and 1, 1 to top Layouts and 2 for list view.
I am implementing a custom surface view, which is called from other activity by setContentView(new SurfaceViewClass(Context)). This class is extending the surfaceView. In the Draw() method which I have added in the surface view, I am displaying an animation that gets triggered, say, every 200 milliseconds, which means that the surfaceview thread gets triggered every 200 msecs.
My requirement is I want to add a button at the bottom of the animation that can respond to events when user has pressed it. How it is possible to do this?
Thank you!
The idea is to have surfaceView(i.e. your graphics) inside a FrameLayout. See the xml layout in the following link.
In the following questions, i have posted the code for the same.
Android:Crash: Binary XML file line : Error inflating class (using SurfaceView)
Let us know if it works!