Ive looked into the ViewFlipper, but defining 40 different views in one XML doc just doesn't seem like a bright idea. I know there has to be a better way, I just don't know how. I have spent some time trying to find a answer with no good answer so far.
I have used the Gallery widget (admittedly quite heavily modified) to display 200 fullscreen images in an image viewer for a client.
Alternatively you could use a ViewAimator with either 2 (in this case ViewFlipper) or 3 views (3 if you want to preload both the next and previous images). If you go for this approach then Laurence beat me to suggesting this idea ;) However I'd add that you would want to extend the ViewAnimator/ViewFlipper class to allow it to accept some type of Adapter.
A simple approach would be to simply contain two ImageViews within the ViewFlipper. Then when you request the next or previous view, set the new image resource for the next view and flip.
If you implement a lazy loader using AsyncTask or a Handler this will stop your UI thread from blocking.
Hope this helps!
You could use a ViewPager (included in the Android compatibility library if you need to support pre-Honeycomb devices).
Related
I've been reading about the include tag on xml, fragments to use on layout for smartphone and tablets but I'm getting more confused than getting a solution to my problem.
My App has 4 screens.
1 - You login and it download info from a json
2,3,4 - From login, Activity 2 load (A list with custom adapter), where you can click one of 2 images to jump to 3rd and 4th activity.
I need now to create the activity 1, 2, and 3 again with different JSONs being parsed, with 1 and 2 having the same layout of the existent ones and 3 with a different layout.
The code I need for them to work is(or can be) the same (Download Task with AsyncTask, button click listeners, etc) I already have for those activities.
I think it's not a goot pratice to copy basically the same getView method, for example, and paste on a new class, right? The buttons wouldn't work on the second range of screens for example.
So, what approach should I take that isn't copy and paste code and change things manually?
Sorry for the newbie question.
If needed I can provide code.
PS 1: I've already did tests with include on xml and copy code but that doesnt look professional
PS 2: Is fragments only for different screens like tablet or I could make something with it?
That's several questions, so here's several answers, including to some un-asked questions:
To the greatest extent possible, strive to remove as much code as possible from your Activities, Fragments, etc. If it doesn't have anything to do with the Android lifecycle or actually putting something on the screen (e.g. parsing JSON), put it in a "plain old java" class. Also, this way, you can share the functionality among Activities.
IMHO, you should never use an AsyncTask, for any reason. They're used with an Activity or Fragment, but don't respect the Fragment or Activity lifecycle, so are often the cause of crashes that can be difficult to diagnose. Use something synchronized with the lifecycle, like a Loader. Or go the RxJava route, where Subscribers can be canceled at the appropriate point in the Activity/Fragment lifecycle.
Fragments can be good for code re-use, but they have a slightly different lifecycle from Activities, so they can be difficult to work with, so use them sparingly and be careful. If you're doing it just to re-use a bit of UI (but not behavior), a layout "include" is probably better. For behavior, a custom View class can be a good alternative to a Fragment.
Don't do HTTP / REST access yourself, using primitives like HTTPUrlConnection. There are a lot of corner cases that are going to get you into trouble. Use one of the several really good open-source libraries that are built for this purpose. I highly recommend Retrofit.
I'm trying to make a kind of quiz-app relative to the music field where I keep on showing random images and the user takes the answers. For each answer I check in a database whether it is right or not. You can see some examples of what I mean here and here. The problem is that I should put in the Android Project a great number of images, which I suppose is not good. So I'm wondering if there is another way for doing that, maybe using sample-images for each element (a single note, a single sharp, the treble clef etc.) and fixing them toghether in some way in order to "build" the final image.. I really don't know. And also, is there a way to verify the answers without internet connection? Thanks in advance.
You can make a CustomView or views http://developer.android.com/training/custom-views/index.html and have it draw differently, depending on exactly what you're trying to convey. You could use a background as well as images, and draw the lines.
Adding custom View and ImageView to a single Layout explains how to include images in a CustomView .
I'm new to Android programming and I'm working on my first application "FunFacts" where
there should be more than 100 cool things to learn about nature, science etc.
My question is: How can I switch from one page to another using two buttons "left" and "right"? which method should I use? I don't think that a horizontal scrollview is the solution.
So if I have 2 different layouts, page one and page two, how can I switch from one to other in my application?
Thank you!
It sounds like you might want a ViewPager. Below is a link to the Android tutorial. This creates a slideshow type effect which sounds like what you're going for. You said you will have different layouts which this will use one layout but you can customize the content and I would think you would want one so it all looks relatively the same
Docs
Update
No, you don't have to create 100 layouts or activities. Just one of each. Following will be a link to a post that explains it a little better. That post explains how it is like a listview in that you add the different pages to your view adapter as you would with a list. You can use the same layout for all and just add new data to it (like a list). Probably store them in an ArrayList or possibly a DB if you have that many and want to have a lot of data attached to them. I hope this makes sense and helps a little. I would suggest starting one with just a couple pages to see how it works, following these examples, and if you get stuck then post a more specific question as to what you can't get to work.
Link
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..
I want to create an activity, which shows a question with 4 answers, and at the bottom of the screen i want to place a timer.
I have already found timer example, and i created a question with the answers. the problem that they are 2 different projects and activities, and i am looking for the best way to implement it. i think i can't show 2 activities on one screen, but i can show 2 views or shell i use the ViewGroup, or maybe to copy-paste one of the activities code to another ( its the easiest way but probably the most ugliest way to implement it).
please tell me what is the best way, that i will study and not to waste time to study all the ways and only then to choose one of them.
welcome to StackOverflow.
You are correct in that you cannot display two activities at once. You must instead look into how layouts work in Android by reading some tutorials on the Android developer guide.
For your layout, I would recommend using a LinearLayout with four TextView objects inside it containing the questions (and perhaps your EditText objects below them) as well as your timer. Make sure they are all inside a ScrollView so the software keyboard doesn't force it all to be squeezed up. This is how I would approach it, but I encourage you to read about how layouts work and use the XML resources.
The Notepad tutorial is an excellent way to get started with views and text entry, as well as using SQLite databases.