Develop Reference

Correct design for using the same data for different views

I am new in the corporate world & from design perspective please correct me if I am doing something wrong here
I am fetching images from Flickr API.
GOAL: Show these images in two different type of view, grid view and listview. Which can be switch through the slide.
So I am using a View pager with two fragments and both of these fragments has separate listeners. So when the response came from Flickr both of these listeners are notified.
In my opinion, this saves two times calling of REST API, but I am looking for even more efficient design or flow through which
Using single listener
Rest API should be called once
Result should be store (Just in ArrayList) and share to both of views
May not choosing two separate fragments
Avoid creating Adapter object two times
Image should be stored in cache
Any tweak or suggestions will be helpful a lot, please comment if you don't understand any part or whole question.

For above problem, the tweaking you are thinking is almost right. Other than below:
What I believe you must create two different adapters to have more control over different views. For example, you might want to show with scale type crop center for an image in list view but scale type center inside for an image in grid view. There might be the different type of thing you may want to perform. So, it's a good practice to make two different adapters, to make the code more manageable.
Again the same goes for the fragment, see if actions in both the fragments are same or can be done with single variable passing. Then only go with a single fragment.
Rest of the things are perfect.

What is the best way to change between different types in a android quiz?

For a school project a need to build a android quiz application with multiple question types. These question types are: Multiple Choice, Textbox, Radio button and a minigame in which you need to sort images in the right order in a draggable gridview.
I think to use multiple activities for this isn't needed and that i just can switch the overall layout between multiple xml layout files for each of these question types if i first check what the type of the question is. Most other posts on stackoverflow are only related to quizzes with one type of question, without minigames in between the questions so i wanted to know what the best method is to switch between these different question types and layouts. At least i know i need a switch/case to check the different question types (for my prototype located in a array) and switch to right type if you press the "Next question" Button that is located under the answers (under the gridview in case of the minigame).
I already searched on the internet for it and i found the following options but i don't know what's best in my case. I also wanted to make the app compatible with android version 2.3.3. Some examples could also help me very much!!
(Adapter)Viewflipper
An Adapter that changes a inner layout
setContentView() of the main activity
Including a layout in another layout and change it
Make some views/layouts visible and invisible.
Make a new activity for each question (if there is no other option)

You can do it with a ViewFlipper. In the ViewFlipper XML, just list each layout for each question type and just have the user scroll through the flipper to get to the type they want. You can probably do this by setting a OnTouchListener and calling showNext() as they scroll.
Setting the correct data for each view is solely up to you; you would just have to match the correct data based on what view they are in to populate it correctly. That's it :)

It depends on how you want to structure your quizes are the questions supposed to be mixed together? Are they all seperate quizes.
If they are separate the easiest approach would probably to implement a view pager. With the view pager it will create a new fragment for each page. From here you have a two options, you can either create a new fragment for each quiz type. Or you can create one quiz fragment and pass an argument to that fragment to select the correct layout. Either way you'll likely want a new layout for each quiz type. As for your minigame you can just include that as a page in your view pager in between two quiz views.
All of the above will work on 2.3 and above if you use the support library. I would recommend checking out some tutorials on viewPager they are fairly straightforward to use.

Two Custom ListViews inside an activity for larger displays

Android 2.3.3
I have an activity where I display "Device's Contacts" in my custom view(imageview, 3 textboxes, checkbox) inside a ListView. What I want to do is, display two listviews with both showing alternate contacts (Splitting the listview into two) side by side. This is because, I want to utilize space on landscape mode of larger displays.
I haven't seen many questions on SO and somewhere I have read that, this approach will mess up scrolling of listviews and will get messy.
So, can someone explain why/how would it get messy and is there another way to use the space in larger displays in my scenario.
Thanks.

This sounds like exactly what the Building a Dynamic UI with Fragments android tutorial was designed to address.
As #ooops mentions you will need to put each ListView within its own container. In the tutorial I linked to, they accomplished this by using 2 Fragment instances, each that loaded different content. Whether you copy their example and use the <fragment> tab (admitidly I don't remember which API level that works on) or use a different container like a regular LinearLayout you should be able to acomplish this easily.

You could do this, but each ListView should be in it's own container.
For examlple How to use multiple listviews in a single activity on android?
But be aware that #Rarw is more correct in the way of good programming practice. Fragments are recommended for such purpose.

Android: using viewfliper with dynamic no of slides, number of slides can vary

I need to implement an application which uses a sliding view (ViewFlipper) for one of its activity, this activity displays information stored on and array and passed from the previous activity via intent. The number of slides or tabs is expected to vary depending on the number of elements in the array. i.e for 4 elements in the array,we shall get 4 slides and when there is only 3, we have the same amount of slides displaying respective information accordingly.
Any idea on how to implement this, an example if possible? I am very new to android development. please help

Create an .xml file now implement a view flipper design the layout of how each pages work. I suggest using a relative layout and add those views inside the view flipper. Seems pretty basic now go search tuts on .xml, viewflippers, types of layout, textviews, and don't put questions here next time asking for answers. We are a community after all helping people with problems who actually tries to do something not for copy and paste people.

For this purpose it's best not to use the ViewFlipper, but instead use a ViewPager to which you can dynamically add 'subviews' (pages) using a PagerAdapter. ViewPager will provide performance benefits over ViewFlipper as it loads (and removes) pages on-demand (like a ListView).
Set-up of the ViewPager is in essence the same as setting up a ListView. You can use the ViewPager on Android <3.0 devices using the compatibility library.
Create your own class that extends PagerAdapter, and set mViewPager.setAdapter(mAdapter);. In your adapter, in the method instantiateItem() you will build your 'page' and add it to the parent with mViewPager.addView(newView);.
For a more detailed example of how to set-up a ViewPager see my answer here.

Custom view in android

I need some valuable advice from you guys...
I have a UI where I have to drag objects from one view to another.
I have a rough sketch of this UI below
I think I have to create a custom view for this. I have to drag a square and a ball from bag 1 and bag2 [both bags are scrollable, can contain 10 to 60 items each] and drop it to the closet one by one. and later I have to find the number of items in the closet. The items in the closet must be arranged in a well maintained fashion [may be ...like 6 in a row].
Where should I start?
How many custom views should I use?
Is there a simple and effective UI solution for this?
Happy coding..!

I would suggest a design with three different GridView objects laid out inside a ViewGroup that supports dragging objects from one GridView to another. The objects would be custom ImageView subclasses so you'd have a place in code to support a drag-and-drop protocol of some sort and because you'd likely want to associate some data that is specific to your application with the objects being dragged.
As for the drag-and-drop protocol, you could consider an adaptation of the Android Launcher drag-and-drop framework or the current drag-drop classes described on the Android developers' website. I don't have much to say about the current drag-drop classes. I have not tried them yet, but understanding them is on my to-do list. However, I have done an adaptation of the Launcher code, and I have written it up on my blog and posted demo apps and source code there. See Drag-Drop for an Android GridView.
With the framework that originated in the Android Launcher, you have a good set of classes and interfaces to work with. Some of the objects include: DragLayer, DragSource, DropTarget, DragController, DragView. The DragLayer is a custom ViewGroup within which all drag-drop operations occur. It delegates handling of all the touch events to a DragController, which is the object that does the actual moving of objects around on the screen. As it does so, it interacts with DropTarget objects to give the user visual feedback that something is being dragged and that a place to drop something is available. A DropTarget is an object where something can be dropped. A DragSource is the interface for objects that can be dragged within the DragLayer. The Launcher framework is a good one because it gives you a way to think about dragging and dropping and how you want to divide up the responsibilities defined by the framework.
The reason I suggest GridViews for your problem is it sounds like you are thinking that way already. The closet has "maybe 6 in a row" so that could be a GridView with one or more rows depending on how screen space you have. A GridView would also work for the container that holds the squares and circles. If that is a good fit, you could study the code in my drag-drop tutorial and see if that makes it easy for you to move objects from one GridView to another.
In my demo program, I ended up with a custom subclass of ImageView that I called an ImageCell. These are views that are on the grid. An ImageCell allows objects to be dragged from them and onto them. For awhile as I worked on the tutorial, I had a custom GridView class too but ended up with the standard GridView. It sounds like you'd want a custom GridView because it sounds like being in the closet is different than being in the other sections. Having it gives you a convenient place for the methods you have not thought of yet.
I hope some of these suggestions prove useful.

Depends on the Android version you are targeting. For 11 and above you can use the built in drag and drop functionality, otherwise you are pretty much on your own. I would normally advice you to implement some sort of a long press action that might even allow you to select multiple items and move them in batches, which would be a really simple thing to implement.
If you really need DnD you should check out this example, it should give you some idea on how to make your own implementation.

I think that bag1, bag2 and closet can be three instance of the same configurable custom view (let's name it CustomBagView).
CustomBagViews should be responsible for displaying items (using a gridview of imageview for example).
I think those will not need to handle drag & drop directly but they should support
removing and adding elements
provide a setOnItemTouched(Interface_class) callback setter.
Then you will need to code a Container custom view (let's name it BagContainerView) that will contain the three bags and handle the dragging & dropping from the bags.
You will provide a handleDrag callback to each bag using CustomBagView.setOnItemTouched, then track the finger motion in it.
When the dragging finishes, you must find where it ends, locate the right 'customBagView' and ask it to add the item to its list.