Testing fragments that access views of the activity they are embedded into - android

I want to create a single activity app with multiple fragments and a favorite action button.
Since I need the favorite action button on every fragment, and it should always be in the same position, the button is part of the activities layout. Basically like the "Basic Activity"-Project in Android Studio.
The different fragments set their own onClickListener and thus need to reference the favorite action button, which works fine when running the app.
val fab: FloatingActionButton = activity?.findViewById(R.id.fab)
fab.setOnClickListener { ... }
But when doing isolated espresso tests, I obviously get a null pointer exception when the fragment tries to set the onClickListener.
As far as i can see, I now have the following possible solutions for the problem:
I could change the production code to make the favorite action button optional, and always check for null before setting the onClick-Listener
I could change the test to not test the fragment in isolation but instead with the activity.
I test the activity instead of the fragments.
Since my goal is to avoid nullables, solution 2 and 3 appear to be better than solution 1. But solution 1 appears to be the easiest of the three.
What is the best practice to test fragments in a single activity app that shares some controls via the activity?

Related

Determine fragment change while espresso testing

I'm testing my application in android composed of 1 main activity and multiple fragments inside in which we navigate.
For my tests I use espresso, and after a click on a particular button, I want to check if the current fragment has changed or not (the part with the button is ok).
So, how can I do in espresso to check if the fragment is still the same than before the click on the button?
If you really want to do this, you can do
FragmentManager fragmentManager = getActivity().getFragmentManager()
and get information about the backstack from fragmentManager. If your fragment has a tag, you could assert that findFragmentByTag(tag) returns something non-null.
But it's normally better to make assertions about the view hierarchy. It's what Espresso was designed for, and it's more in the spirit of black-box testing.
So I would suggest finding some distinguishing feature of the new fragment, such as the page title if there is one, and asserting that that view is present using the usual Espresso methods, e.g.
onView(withText("Page Two Title")).check(matches(isDisplayed()));

switch to a new activity, instead of switching fragments, when jfeinstein10's slidingmenu list item is clicked

I have seen a few questions raised on this topic (for e.g.: https://github.com/jfeinstein10/SlidingMenu/issues/5) but I am still unclear. I hope somebody can clarify this.
Context:
See https://github.com/jfeinstein10/SlidingMenu
I have an android app that organizes screens by activities and fragments (i.e.) each screen is an activity containing one or more fragments.
The new requirement is to add a sliding menu (similar to what this library provides).
Issue:
It appears from the examples and discussion that the right model would be to have just 1 MAIN ACTIVITY that will then switch in/out fragments belonging to the different screens. In fact the author mentions in the above thread: "If you were to launch Activities based upon the list selection, then you would not have the behavior where you swap the views that you're talking about. " and also "You can't put an Activity into the above view. That doesn't really make sense when you think about what an Activity is. ".
Why doesn't it make sense? Obviously, I am missing the point here.
Question:
Given that my project already contains multiple activities (one corresponding to each screen), is my only option then to re-organize the project to have JUST 1 MAIN ACTIVITY, in order to use this library? Or alternatively, is there any way to launch a new activity when a list item in the sliding menu is clicked, and still observe the sliding menu behavior, [EDIT- added the last part to be more clear] or in other words, on how exactly to use this library within my existing app design.
Thanks in advance
First, you can't have an Activity inside another and activities are completely different from views as stated in the docs:
An activity is a single, focused thing that the user can do.
Now, to answer your question, it all depends on how you want your app to behave. You could have your activities with the sliding menu implement the onClosedListener and switch to the selected activity from there. This will give you the animation of closing the menu before switching activities. It will also give you a weird effect since every time you select something from your menu you'll see the animation of a new activity coming to the front.
I think the best approach would be to have a "common purpose" between all your sliding menu options. For example, in one of my projects I have to allow the users to select between lists of different types of data. When the user selects anything from the menu, I load a new list fragment into the right corner where he may choose the item he wants to view or edit. That's the app entry point and also the only place were I have a sliding menu in my app. It is pretty much the same for every app that implements this UI design pattern. Look at google+, currents and youtube where the side menu lets you choose which feed or content to show. Once a user makes a selection, just open a new activity for the selected item (a g+ post, a video, a news article, a tweet or whatever it is).
Your app doesn't have to have lists of different data or anything like that to use the sliding menu, but keep in mind that the activity with the sliding menu should have a clear, focused goal with respect to its functionality and purpose. Having a sliding menu because many other apps have one is a bad choice, you should use it with a specific objective. Also keep in mind that applying the sliding menu everywhere would interfere with the platform's navigation pattern and lead to an overall bad user experience since it wouldn't behave as the other apps.
It doesn't make sense to place an Activity into the above view because the Activity is the main controller for the view of each screen. The Activity also shows views and keeps track of Fragments (which in turn are mini controllers, with or without their own views). So placing an Activity in the above view would mean that you would place an Activity in an Activity... Wich is impossible.
From what I can derive from your text I think it would be wise to read through the Android developer guide on Activities and Fragment again (http://developer.android.com/guide/components/activities.html) to get a better understanding of how the concept of Android works.
Now to your question:
I am not clear on what you are trying to achieve but if you want your app, with menu to behave like, say, the Google+ app then one way of doing it is to implement a base class that extends the Activity class (or what ever base Activity used in your project) and let the base set the SlidingMenu. Then you would simple extend your base Activity in each of the Activities that are supposed to have a menu.
You could also do it the way you describe it, but then you would end up with a classic example of a God object (http://en.wikipedia.org/wiki/God_object). It's a neat way to practice your Fragment juggling skills and switching between Fragments instead of starting new Activities does have it's use cases, but I still wouldn't recommend it for a project with more then a few views.
Here is the answer that came closest to the issue I had - http://www.verious.com/article/polishing-the-sliding-app-menu/. Scroll down to the bottom of the page to see the last section titled "Using the fly-in app menu between Activities". This is one option if you have a lot of activities in your existing app and want to avoid extensive re-factoring. I haven't tried this out yet but its worth being aware of.

Android - how to keep UI elements static between activities?

I have a navigation bar with buttons which I would like to share between multiple activities:
Currently, when I start the same activity (for example, click on LOST.DIR) the whole screen changes, including the navigation bar (new list of folders appears).
I would like to keep the navigation bar static (to persist between same activity types and not to change or re appear after starting a new activity).
Is this possible?
It sounds like you want to use one activity and fragments.
But, if you really must use multiple activities. Another approach would be to use an actionbar, (actionbarsherlock is great for this) and have the menu switch between your different activities. The menu drop down can either be a list of icons on the action bar or a drop down spinner located in the top right of the actionbar. This actionbar will be static throughout your activities and consist of the same list of categories (i.e. the ones of your navigation bar).
Not straight away. Activities are exactly the opposite of what you want: they are independent pieces of interface.
You can use Fragments, or embed your activities in a master activity. TabHost does this, for example.
One approach for total control is to write your own custom class which takes a LinearLayout as a constructor argument and handles the visibility, click dispatching (via delegates), images etc of each button.
Add methods to do all of the above and whatever other functionality you need.
Create a layout.xml and it in each of your Activity layouts.
Instantiate your button bar class in each Activity and pass it the reference to it's layout that you get with findViewById on your content view.
As others have said, there are existing solutions and you might ask "why invent a new wheel". I have just such a class I use in many of my projects and it was a lot of work to do version one but now I have a class which I can totally control, add to, fix and customise with ease.
Something like this:
bar.setButtonClickHandler(Button.Favourites, favouritesButtonClickHandler);
bar.setButtonVisibility(Button.Edit, View.INVISIBLE);
etc
I've used a LinearLayout but if I have have the need to use something else, it's a simple matter to overload the constructors to accept, for example, a RelativeLayout argument.

How to Use Menu in Complete Application in Android

I am working on an application in android. Where I need to use menu through out application. Actually it will be used for navigating within application from one activity to other and so on... I am wondering that it will need to write onOptionMenuCreat and OnOptionMenuSelect methods in each activity. Also if I make one parent activity where these two methods could be written even then on each activity Option Menu will be created again. So handling same menu while it is created again is becoming work of afaik. Any good design suggestions are most welcomed. Another very important thing how to map that user was on witch activity last time while selecting same menu again. My app has total five menu options so that means there are five different ways to move within application simultaneously.
Please Do tell me solution for both issues. Thank You.
You create the Menu in an Activity and inherit all the other Activities from this Activity.
To answer the second part.
create a different method for each menu handling in the parent activity. If you need a different menu/menu_item behaviour for your activity, just override that method.

call a method in the main Activity. From a Custom View class

i am using the following method in a new application i'm developing.
there is a main activity, which instantiates different classes that extends RelativeLayout, and i'm using setContentView to switch between the different modules of the application.
i wonder if this is a good approach or necesarily i have to use different activities to the several screens the app haves.
I'd recommend using different activities, then you automatically get navigation between them via the back button. Plus, there will be subtle things that won't work right if you do it the way you're describing -- for example, Android automatically saves the focused control when you switch activities. It won't do this for your content views; you would have to save/restore focus yourself.
Alternatively, if it doesn't make sense for a user to go "back and forth" between the screens of your application, then you could still implement the application with multiple activities, using android.app.TabHost. This is what the Contact app uses, for example. Then each screen is just a sub-activity, and the whole app is really treated as a single activity. And if you want, you can use TabHost without actually having tabs. You can hide the tabs and enable navigation via buttons or menu items instead.

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