I have a native Android app that I am translating to Flutter, and I am not sure that I'm on the right track. I implemented the bottom navigation bar functionality by following the documentation, but I'm not sure what's the best way to navigate between what were Fragments in the native android project. For every widget I select with the BottomNavBar, I need further "pages", while the BottomNavBar has to stay on the screen, and I also need to pass data further "down" the navigation graph.
I thought about creating a custom widget which stores the subpage you are on, same way as I did with the BottomNavBar, but this seems like a hack, especially that I would also have to store the parameters that I have to pass to the new "fragment", and the pages should keep their state after navigating away and back.
Is there a better way to implement this functionality?
I use the IndexedStack as this article elaborates. I think it's probably a good solution.
https://pub.dev/packages/persistent_bottom_nav_bar/
It occurred to me after asking that I should check for a package, and here it is, does what I need.
Related
I've recently been looking into the navigation system that Android uses with as intention to port my iOS app that uses an UITabBarController containing multiple UINavigationControllers. To replace the tab bar (which is not available on Android) I settled on using the built in DrawerLayout.
From what I've read, navigation in Android is generally done by creating an Intent, providing it with extras and then just replacing the current activity. This automatically makes sure the back button works, and optionally the back button in the top left if enabled.
However, I am not sure how to implement this way of navigation with the navigation drawer. The tutorial tells me to create a DrawerLayout containing a FrameLayout and a ListLayout where the FrameLayout will contain the actual application and the ListLayout will contain the navigation. This would mean that when I use the method described above to "navigate", it would replace the activity and thus removing the drawer.
What would be the best way to implement what I want (basic navigation with back button support while maintaining a global drawer navigation menu)? The possible options I can come up with is always keeping the same activity and dynamically replacing the FrameLayout, but that would mean a lot of boilerplate to render and possibly a hack to support the back button (and there would be no animations :(). The other option would be to just render the drawer on every activity (via subclassing or something), but that would mean that if the user navigates a lot the back button "stack" would become quite large.
I have tried to explain what I need in as much detail as possible, but it is quite hard to explain the concept. Basically, I want something similar to the UINavigationControllers in the UITabBarController.
You can either have one Activity with one NavigationDrawer and present the user with different views by switching Fragments back and forth within that one Activity. You would use the FragmentManager to switch between different Fragments.
Or you can use multiple Activities that all have a NavigationDrawer.
Second option might sound more difficult but it really isn't. You create a base Activity that all your Activities inherit from and all let them have their own NavigationDrawer, no problem.
Sure there's something in between or something completely different, but that's the most straightforward approaches I can think of.
The tutorial you've probably used (the one with the planets) is imho a bit misleading because it assumes a very basic app structure. If you have only little different 'screens' that might work, for a very complex application it's not suitable (again, in my opinion).
I've always opted for the second option because handling the navigation / backstack is just easier with Activities / Intents.
There's loads of different flags that you can set to your Intent to influence their navigation behaviour.
Also see this and that documentation. These documents might have been written when the NavigationDrawer pattern was not all that common but they are still useful.
I have a design for an app that will have a row of buttons below the action bar. Each button will open a different fragment. I am aware of ViewPagers, but I do not want the swipe between fragments functionality. I know that I can disable this functionality, but at that point is it worth using a ViewPager? I know this is a pretty common design paradigm, so how do most apps handle this sort of thing?
It seems like the ViewPager will provide some nice functionality out of the box, like switching between fragments and what not. So, I am leaning towards using one, but was hoping someone could provide some feedback on this approach.
Thanks!
Keep the buttons in the layout of your main activity. Have them call a function lets say loadFragment(Button button) on click.
This function then handles switching of the fragments, and you can change the display of the navigation buttons inside this function itself to highlight the appropriate button or something equivalent.
Google Design is always worth the reading.
Check http://developer.android.com/design/patterns/swipe-views.html for details.
Personally I have used ViewPager with tab layout for swiping purpose and it makes it easy to me to synchronise the transitions ( tabs and pages) where I put a red circle to the tab corresponding to the viewed page. With this approach I got a clean separated code.
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.
I am trying to build an app in which I want to go to a new page through swipe-say. I have about 10 different pages and I want to go to these pages by swiping. Can I implement these pages as separate activities? Can I swipe from one activity to another? I strongly like to implement these pages in seperate xml files rather than creating everything in a single xml page. But as far as I have searched, there are no proper tutorials or blogs giving an appropriate example of a program implementing swipe. If possible, provide some working codes.
Thanks in advance.
It seems that a FragmentPager is what you want.
Examples and code on the linked page.
If you build for earlier versions of Android, the necessary code is included in the Android Support Package.
In Android, swipe is not identified as a particular gesture.
You can use a OnTouchListener registered on your view, and animate your view if the gesture exeeds a certain threshold.
You can then launch a new activity, or in a simpler way, use a viewFlipper.
Please try the attached link View flow.
I feel it will fit your needs perfectly. You can even create different xmls and inflate them into different view objects and then use the "view flow" to switch between them.
The "view flow" is perfect for handling both simple & complicated views. The flow indicator on the top of the screen is optional.
I hope it helps..
Which you think is the best way of doing a wizard like application (user can navigate between screens with a next and back button, and each screen has to save some state data) in Android platform.
I mainly can think in two approaches:
Having one activity+view for each screen and then i make the screen switch by calling each activity. What make this nice is that i can use the system back button as my back handler and i don't have to take care of that myself, aslo each activity will save it's own state.
Having one activity and many views, and what i switch views in each screen change, this helps me re-use more code, but makes saving states a mess.
What do you think? Which is the best way of doing this on Android?
This library is no longer being developed.
Use Android Navigation Component with combination of ViewModels to build a wizard flow.
I've developed a lightweight Android library, which is built on top of Android's ViewPager that can be used for creating wizard like activities. Check it out: WizarDroid.
I suggest going with 2 as it fits the goal of activities and views. Saving state in this case is easy - if you use the MVC pattern, you can simply have a model object that is passed along to the views. Each view will have portions of the model that it can read/write. No matter where you are, the model should always have the current state. If you get disposed, just save the model. Restore works automatically since you already read from the model when you show each page.
I've gone with the first approach as it seems more natural. Another app uses ViewFlipper for switching views but that's far from anything like wizard.
9 years ago this was obviously a very different kettle of fish - but I think the best way to do this now is with Fragments.
Have a Fragment for each 'page' in the wizard, letting it handle its own lifecycle and state.
Change page from within each Fragment with Fragment.getFragmentManager() - this returns the FragmentManager from the parent Activity, allowing the Fragment to replace itself.
I think 2 is better. Put each "page" in a view and then just alternate between showing and hiding them. Makes it trivial to do nice transitions. What state are you thinking of maintaining? The only one that doesn't work automatically would be focus and I think you probably want to reset that every time you switch pages. It is also trivial to catch back if you think that is the right behavior for your app.
With 1 you can reuse almost all of your code (just define your own WizardBase class) but I think activities are much slower to launch (and require more memory) than switching between views.