I have a button which is basically used for start/stop. So initially the text of the button is set to start. I attached a OnClickListener to it. So whenever it gets clicked i change its text. So if it was start it become stop and vice-versa.
The problem comes when i change my phone view from portrait to landscape or vice-versa the button text gets reset.
So for example I clicked the start button---it changed to stop. Now if I tilt my phone to change the view the button text gets set to start again.
Am I using the button in a wrong way?
You should save your button state. When screen orientation changes, onCreate is called and all your app variables are re-intitialized. Read more here http://developer.android.com/reference/android/app/Activity.html
No, you are using the button in the right way.
The thing what you are seeing is "configuration change". When you are tilting your device, Android recreating your activity and recreating all it's views (so, they getting default captions as them described in XML).
You need to do the
disable configuration changes for your Activity. To do so, add the following to your manifest's activity tag: android:configChanges="orientation|keyboardHidden". It is not suitable, if you have different layouts for landscape and portraint orientations, when you need to...
handle the configuration changes by overriding onSaveInsatnceState method of your Activity, save a state there and then use it in onCreate method.
See this article for further explanation
Related
I have an Activity which can open 2 different Fragments by 2 different Buttons. By the default that Activity when it creates, it is opening a Fragment, we call it "The Main Fragment".
The first Fragment to which we are going over by the first Button we meet zero problems with the Rotation, but the second one after the rotation disappears and the screen shows the Main Fragment's content. When I tried to rotate the screen back, I see the Main Fragment's content again. But why it is so, if I didn't write any code, which must return me to the Main Fragment without clicking a button.
What assumptions do you have?
Why this is happening ?
Default Behavior, Actiivty is getting recreated on orientation change so your fragment are.
Explanation
You need to understand Activity Life Cycle to understand why this is happening.
First, “rotating the screen” is not the actual scenario we are talking about today. Because any configuration change will cause Android to restart your Activity. A configuration change might be the device rotating (because now we have a different screen layout to draw upon), or it could be a language switch (because we need to re-write all those strings, which may need more room now OR it could be the scary RTL switch!), or even keyboard availability.
By reloading your app, what the system is actually doing is calling onDestroy() and then immediately calling onCreate(). This way, your Activity is as fresh as possible, with all of the right creation data (even though the user has been with you the entire time).
Now you have following option -
Either Fix Orientation for your app from AndroidManifest.xml
But oviously that is not a very good experience for user.
Save activityState with onSaveInstanceState()
This method will be called before onDestroy(). And, when your Activity is created, there’s a matching step onRestoreInstanceState(), which will also be called automatically. All of these automatic steps mean that you can let the system worry about saving and loading your data, because you planned ahead and mapped out what was important. (Or, you can skip onRestoreInstanceState() and load your saved state from the Bundle that comes with onCreate().
In you integrate Fragment in activity, because activity is getting destroy() so your fragment will also destroy() and will be recreated.
Please take a good read on Handling Configuration Change and this.
Once you understood the concepts things will start falling into your but it will only happen if you will complete your learning curve.
Happy Coding !
That is because onCreate is being called every time the screen is rotated. Probably you are displaying The Main Fragment from your onCreate method. You will face the same issue if you put your fragment display logic in onResume because just after onCreate, onResume is called.
Solution: store the fragment on top in shared preferences that way you know what to display every time onCreate is being called.
In my settings activity, I want to check if the Edittextpreference is empty, before exiting the activity, clicking on the android.R.id.home button or on the back button of the device. If the edittextpreference is empty, I have to do something, like change its background color, and avoid the user to exit settings. But the problem is that if i have two edittextpreference, and only one is empty, one edittextpreference has to be with different background, and the other needs to be as it was.
Is there any way to do this? Maybe if it is not possible using the equivalent of edittext.setError()?
I have an app that uses this RibbonMenu and I wanted to know if it was possible to use the menu items to change the ContentView of the Activity instead of another activity to reduce the size of my app. I've tried doing this already,and it changed the content view perfectly, but i was not able to press the home button. I'm in a bit of a rush here, but i'll try to post code if anyone asks for it. thank you!
Menu items is UI element. It does nothing by itself. It however can trigger some more actions in your code. As for changing activity layout, yes, you can call setContentView() at any time you want.
to reduce the size of my app
this is not the way optimalizations should be done
My activity A is a game and it does some background operations. When I press a button in the contextual menu, I want to pop up a "small window/dialog/subactivity" (lets call it B) that appears on top of activity A and displays some data about those background operations. But I need to keep the focus on the activity A in order to continue interacting with it (playing the game).
In essence, I want to be able to see the data display by B while playing the game.
I'm not really sure how to implement this. After reading the documentation I have the next conclusions:
I know that I can't use Dialogs because the have the focus. Is it possible to avoid this?
Using a subactivity with a Dialog theme it's another option that looks tempting...but I believe that the subactivity has the focus. Ditto.
My last option is to try to add a LinearLayout with my data to the main Layout, "sharing/splitting" the screen. It's not pretty, but at least I know that this is possible. What I don't like about this approach is that I use the width and height of the screen.
Any suggestions? Solutions?
PS: I found some this thread here that are very related to my question:
Android ==> Sub Activity?
Create an Activity with style Theme.Dialog. This is a normal activity which looks like a dialog, while being modeless and accepting events.
Additional catch is in setting WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL and resetting WindowManager.LayoutParams.FLAG_DIM_BEHIND.
See this answer for complete example: timed modeless dialog
Why not use a FrameLayout that is apart of your Activity? Just ensure that this View has a higher z index (make sure you declare it last in your XML layout or create it at runtime). That way you never leave your Activity.
RoomInfoActivity.java: http://pastebin.com/L9fFsFeH
(note: this is the 3rd activity launched by the same application, not that it should matter..)
AndroidManifest.xml: http://pastebin.com/QbvQaTf3
room_info.xml: http://pastebin.com/DFNABSNF
Image: http://dl.dropbox.com/u/16952797/temp_stuff/elfapp_ss04.PNG
(note: when I click on the button, "nothing" happens.)
Description: So what happens is the code compiles just fine, and the .apk is launched and run without any issues, but the RoomInfoActivity doesn't reflect the changes that are supposed to be made (such as changing the text of the TextViews and Button) when I click on the button. I'm looking for the least complicated way to do these.
EDIT: I have now made a change, I added this line buttonCleaned.setClickable(true);
under this:
rumInfo.setText(getIntent().getExtras().getString("entry"));
buttonCleaned.setText("Färdig med städningen");
rumStatus.setText("Status: "+checkStatus());
Is your onClick() method ever called? I think you need to set the Activity as a click listener on the button, using the setOnClickListener method.