I'm kind of new in Android and i'd like to know if there is a way of displaying a xml file (with the same 'controller') from different activities?
In other words, I'd like to display a list of CardViews with the same content and listeners in two different activities (exactly the same way). What is the best way of doing it?
There's ways to do this if I understand right.
You can use same xml in different Activities.
You can start same Activity twice.
You can use fragment to display same content.
Related
Is it advisable to stack up multiple views and depending on the preceding activity, show the appropriate widgets/views to user? e.g. To have 2 or 3 forms in 1 layout file(xml),and show one view depending on what the user wants to see.
you can use Fragments... Add the right fragment to activity based on the preceding activity.
Fragments do this. Stacked views are nice for collapsed elements. There are uses for them as well. The choice is based on your particular use case. From what you've said, I would recommend Fragments.
The nice thing about fragments is that they handle life cycle events (like activities) but without the need for serializing and parceling data to communicate among your fragments.
As for your question "Is it advisable to layer views?" I would advise against layering different forms UI. The xml design and maintenance can grow hair real quick.
Fragment is the solution in android when you want to show some specific layout to the user create 2,3 fragments android depending on the condition load the appropriate fragment.
You can go through this to get started on fragments.
https://developer.android.com/guide/components/fragments.html
I'm working on an app that has like ten or more listviews across different activities, each of them uses a different adapter with a different data model and item row layout.
When you click on a row, the app shows a fragment with the details, nothing new.
My question is about the best approach to do this.
I could create ten fragments with a listview and ten fragments with a
details layout.
Or I could always use the same fragment and use a
different adapter and inflate a different details layout, depending
on a TAG, for example.
Another way for the details fragment could be
containing all the layouts in one, showing only the one I want and hiding the rest.
I also could implement a base fragment and extend it changing the layout in the children.
So my question is not about coding this, is about the cleanest and efficient way to do it.
Is it better to reuse one fragment or have multiple files?
Is it better to have a lot of files with a little code or a reusable file with a lot of code?
Thanks
I want to divide my screen into four parts and add activities in each part. I am not interested in using fragment. Each activity should behave independent of other. Attached photo is showing what I exactly want to do.
In each child activity I want to add VideoView or WebView depending on the selection from menu item.
How can I do it. I didn't find any way to add activity to an activity.
Thanks :)
PS: Activity means Activity not fragment.
i strongly recommend 'using fragments' in your case as ActivityGroup is deprecated in API 13..
The only way you can do it by using fragments. Here is the simple example on how to add multiple fragments on single activity Link
Edit link
You can achieve this design by using four fragments, one for each child view inside a single activity.
The recommended way is to create a single XML layout for your activity, and create four fragments inside that layout.
I've read Activity and Fragment sections of Android API and many Q&A on these two, but I still don't have a clear understanding of some points.
When android SDK creates an activity for me, it also creates a fragment for it. From what I know I can bind several fragments to one activity and switch them as I like. But I don't understand if I ever have to add any components to activity xml file? I mean all layouting and buttons are in fragment xml. In what situations and why would I need to use activity's xml file? Can I make buttons, for instance, both in activity xml and fragments xmls? Is it a good practice?
What logic should be generally implemented in activity class and what in its fragment? For example, I think that Fragment class is needed only to get data from UI and pass it to activity. Is that right?
Thank you for your patience
An activity is basically a screen in your application (think of it as like a webpage) with all associated logic. A fragment is a sub-activity, a portion of an activity with its own set of logic and UI.
You should use a fragment when either you use the same UI in multiple activities, when you want large parts of your activity's UI to change in and out as people take actions, or when you want to rearrange large parts of your UI in different layouts. When none of those are true you should ignore fragments and just use activities directly. In my experience it ends up being about 80% activities and 20% fragments, but it really depends on what type of apps you're developing- tablet apps use a lot more fragments, for example, because they have more screen real estate.
I am trying to create a layout in an activity that will look different in landscape and portrait, however it will contain the same sections, just in different places on the screen.
Most examples I find on fragments is always the list and detail, which is not what I'm looking at.
In my example I have, amongst others,
a scrolling image section (carousel)
a page title with some brief details
a carousel of thumbnails
two buttons
full details of the page
Now in the landscape layout, the image section will always be on the left side with down the right side, the page title, carousel of thumbs, two buttons and full details.
In the Portrait the title will appear at top, with image carousel beneath, then thumbs, then buttons etc.
The way it works in my head, is that each section should be a fragment, and then depending on the layout file in the respective res/layout folder corresponding to land/port, the fragments are arranged accordingly. But I'm also thinking is each section a whole fragment? Or could it be a separate view that get's loaded in, but just in a different order depending on the screen orientation.
I hope that made sense?
Does anyone have any good tutorials that explain exactly when you should and shouldn't use fragments. All the usual suspects just list the list/detail example, which is not applicable in my case.
tl;dr Can I use fragments as modules/blocks in various layouts or should I just create other layouts and display them inside the main layouts.
Fragments can be used to have split screen and to store previous state unlike views. It is difficult to manage back button with views
If you just want to change how the screen is laid out, the answer is neither. You can define orientation-specific resources (either a separate layout file for each orientation or different dimensions/constraints for each orientation) and the system will just provide you with the correct resource set for the current orientation.
That said, it sounds like you may be describing a modified version of master/detail flow. If this is the case, fragments are a good way to go since the landscape view is actually several separate screens in the portrait version of the app, so each section needs it's own state and lifecycle, which fragments provide.
Now, I know you said you wanted an example beyond a list and detail view, so here's some more details on when to use fragments:
Fragment, like activities, have state and lifecycle. Custom views do not have lifecycle and are completely dependent on the activity or fragment containing them.
You might use a custom view when you have a widget on screen that is used in multiple places and is just like any other view – bound to the activity when the layout is inflated and controlled from there. It's a way to either reduce duplicating combinations of views in your layout or to draw a custom view that doesn't exist yet.
Fragments are good when you need some state or lifecycle for a section of the app that might get used in multiple places or shouldn't be logically connected to the activity it is contained in. If you use the new Navigation Component, you actually just define one activity and then each screen in the navigation tree is a fragment that gets swapped out as the user navigates around the app. Here each child component on the screen (each "screen" that the user navigates to) has it's own lifecycle, business logic, etc, so mixing the code for all of that in the activity wouldn't make sense.
So the question comes down to what you are trying to build, and this may be a case where the best way to learn the difference is to try each option out as bit. The differences become more clear with practice using them. As a general rule of thumb, personally, I only really use custom views when I am trying to make a new view that doesn't exist elsewhere. If what I'm trying to do is simply a matter of laying out existing views in a new way, the answer is probably some trick in the layout file or layout code inside the activity. If I'm trying to make a stand-alone piece of the app that does stuff, especially if it also appears in multiple places in the app, I'll probably be building a fragment.