So, I have to create few items, like Buttons and TextViews, from a service.
Since I need to pass along a Context when I create a new one, and since my service doesn't have one, I thought about doing it like this
Button button = new Button(getApplicationContext());
It works, but is it the best solution? I read a lot about how you have to be extra careful when using application context, so I'm not sure if it's the proper way to achieve what I need
Thanks in advance
I never used Service instances for that so, this is new for me. However, I stumbled upon this question about overlay service which gives quite cool solutions. As per your question I guess the following should work within the scope of your Service and is safer:
Button myButton = new Button(this);
Related
I've noticed while trying to switch from one Activity to another within a glass app I've built, the menu seems to get messed up and I get left with a ghost activity displayed in my LiveCard that cannot be closed.
I've reviewed a few of the examples (e.g. Compass) but we don't have any advanced examples for navigation it looks like. Can you help out with defining for me the agreed upon convention thus far for building navigation in apps? This will help fix my issue because I realize I'm creating multiple LiveCards which doesn't seem right.
Activities: Should I create multiple activities or should I recycle the same Activity swapping out the UI instead? If multiple activities, is it a good idea to destroy the previous Activity's service upon loading up a new Activity?
Services: In a broad sense, should there be a single service used by all activities to handle the navigation (switching between Activities)? If just one service, should it ever be stopped/restarted? How do you switch between Activities using the service because we don't have a reference to the service from the Activity or the Binder? Or should there be a service for each Activity to handle the navigation?
LiveCards: I believe only one livecard should be created, so then how do you switch between Activities without creating a new one? Is it the convention to keep a global reference for any service to be able to use this LiveCard?
I've asked a lot of questions and I could be way off base for some of them, but I can use any guidance! I can't really find a good guide on google for defining the expected behavior for nagivation. I come from 3 years as an Android dev, so feel free to be complex in your answers! Thanks guys.
EDIT:
In case this helps, here's the code I'm using to go from one Activity to the next:
mLiveCard = new LiveCard(this, GlobalConstants.LIVE_CARD_TAG_ACTIVITY2);
mRenderer = new MainRenderer(this);
mLiveCard.setDirectRenderingEnabled(true).getSurfaceHolder()
.addCallback(mRenderer);
// Display the options menu when the live card is tapped.
Intent menuIntent = new Intent(this, Activity2.class);
menuIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK
| Intent.FLAG_ACTIVITY_CLEAR_TASK);
mLiveCard.setAction(PendingIntent.getActivity(this, 0, menuIntent,
0));
mLiveCard.attach(this);
mLiveCard.publish(PublishMode.REVEAL);
We're probably all pretty new to GDK so I'm certainly not more of an expert then you.
I'll share with you what my experience is so far:
Activities:
I only use these when i want to create Immersions. I think the only reason to decide if you want to have multiple or one activity should be readability. If an immersion is all you need then you can start your activity directly instead of using a service.
Services:
I found it useful to have one central service. Especially in projects where I have state full objects with a lifecycle that spans multiple activities. In case your navigation depends on the state of e.g. a connection it also makes sense to let the service manage the navigation e.g. start new activities. Activities can interact and provide results to the service with whatever method is appropriate e.g. Intent, Broadcast, Binder, Singleton...
I usually go through the list and take the first one that fits the requirement. If i can do what I want to do with intent's then that's usually my first choice.
LiveCards:
A central service would also be a good place to manage a livecard that you want to share across other activities. Again the method to expose the live card interface to activities depends on what kind of interface you want (abstract vs direct).
Let me know what you think.
I am trying to call a new activity using an intent, but every time I call it, I can see a new "window" open on my android device. Can I call a new activity that will be in the same window? What I mean is calling new activity without visually seeing that it has been opened.
Hope you understand my question :) Thank you!
I think what you are looking for is Fragments
Start reading Here
Fragments actually use the "same" window (Activity) and just replaces layouts and views - I think exactly like you want.
If you want to run something like a unix-demon code(this mean a program that is only executed in the background without no visual components) you are looking for a android Service.
http://developer.android.com/guide/components/services.html
Otherwise if you are looking for a visual component that don't create new windows but refresh the old one, you could use the Fragment class if your android version is 3.0 or higher.
http://developer.android.com/guide/components/fragments.html
In an Activity content view, create an empty relativeLayout.
As mentioned in previous answers, create fragments and replace this relativeLayout with the newly created fragment using FragmentManager.
FOr reference use this.
Its really easy. try this.
I've got this question regarding Android activities and AndroidManifest.xml. The question arised when I was working with Java servlets, and wanted to create a "module-based" or something similar to plugin based server. This is working fine, and I can dynamically load the servlets I want, using a code approach similar to this: Dynamically add a servlet to the servletConfig. The servlets are dynamically found and mapped during the server startup.
The question here is not how to find the proper activities, or how to create a new instance of them, or how to start them, that part I have figured out. I can iterate over my packages and find the appropriate Activity-classes, create new instances of them and add them to a list.
I've been using a interface which all the Activities must implement in order to be a valid activity. That way, I can create new parts, extentions or new features for my application, and everything just works. In my application I have a list of button that users can click on, and the button list is generated by adding them to my view using a ListView.
private void displayLoadedContent() {
View v = inflateLayout(R.layout.buttonlayout);
ListView view = (ListView) v.findViewById(R.id.list);
view.setAdapter(new ListButtonAdapter(this, content));
}
where content is declared as
List<MyActivityInterface> content;
and ListButtonAdapter extends BaseAdapter.
So no problem there. The problem is that I have to declare each and every single one of my activites in AndroidManifest.xml. That file is like a big list of possible acitivies to display, and kind of messy, so I'm not going to display the code here.
I realize that I'll have to add one activity to the manifest, but I was hoping that the one activity should be enough. My approach can in many ways be looked as a Front Controller pattern, where each of the activities is responsible for loading and displaying the acitivity they need.
I'm simply asking if it's even possible to dynamically registrer activities in the manifest (or allow them to run in another way), and if no, is there any other valid solution?
Android requires that each activity to be registered in your AndroidManifest.xml file ahead of time. When deployed, your app will live on a device as an .apk file, which can't be modified (aside from being updated/replaced with a new APK).
If I understand the question correctly, you simply don't want to have to list a large number of activities in your manifest file? Fragments don't need to be registered in the manifest file, so if your goal is to dynamically swap out UI components, that would be the answer. Fragments are available back to 1.6 via the Support library.
Is it better to start a new activity or just set a new content view in Android?
I usually start a new activity when I have to change the whole environment, but IMHO I think it's too onerous when I need to keep the other activity alive in the background.
On the other hand, I could have a single activity and just change the layout when I have to set a new environment.
Which is the better way and why?
Search for 'Pattern one activity, multiple views. Advantages and disadvantages' on stack-overflow and look for the answer by #CommonsWare
_alerts = new Intent(homeActivity,Alertss.class);
homeActivity.startActivity(_alerts);
...
...
...
homeActivity.stopService(_alerts);
I need to stop the Activity i created from the object where i created it. I tried it in the way above but it did not work. Can any one suggest me a way to do this.
You can use Activity.startActivityForResult() and then Activity.finishActivity() passing in the same result code you used for starting it.
However, this does sound like something that would be better done just as a Dialog.