Develop Reference

Multiple activities for displaying many images?

I developed an app for the iPhone that I would like to make for Android. However, because I was self taught with Xcode, I approached the project incorrectly. My app in it's basics loads a certain picture from a List View when the user selects the certain button associated with the picture they want. I had no programming experience when I started, so I just linked by drag and dropping roughly 300 buttons to 300 different scenes which displayed 300 different pictures in Xcode. Yes, it was very time consuming... My question is how should I approach my project to do the same function in Android Studio, but minimizing the amount of activities. I have the idea that it would be more beneficial to use code to have one List View activity that incorporates many buttons, that when pressed, will display the particular picture. Any recommendations for tutorials or videos as a place to start as I learn my way around Android Studio? Or am is it hopeless and I will have to have another roughly 300 Activities in Android Studio.

You can use fragment for acheving your purpose.
A Fragment is a piece of an activity which enable more modular
activity design. It will not be wrong if we say, a fragment is a kind
of sub-activity
Fragment you can think of it like a sub activity, which sits with in
an activity and which contributes its own UI to the activity screen.
Fragments are always part of an activity. With out an activity, a
fragment will not exist. So your fragment life cycle will always be
affected by activity life cycle. An activity can contain more than one
fragment. Similarly a fragment can be re used in multiple activities
Below links will help you to know more about fragment and how it's implemented in an android application
https://stackoverflow.com/a/13757241/4247543
https://www.raywenderlich.com/117838/introduction-to-android-fragments-tutorial
https://www.tutorialspoint.com/android/android_fragments.htm
https://developer.android.com/guide/components/fragments.html

Should each Fragment have its own Activity?

Android Studio 0.8.10
I have developed an App that has 3 fragments. I have just used 1 Activity and when I want to display a different fragment I just replace the existing fragment with the one I want to display. However, as I have 3 fragments now, and maybe more in the future, I think this will get harder to manage.
I am just wondering what is the design pattern when programming with multiple fragments, should each fragment have its own activity?
I will be scaling this to Tablets in the future, so I am not sure what impact this will have if I stick with the multiple fragments and single activity.
Many thanks for any suggestions,

should each fragment have its own activity?
Yes, but you can also use nested fragments.
I think this will get harder to manage.
you are right but
i think you must match your app with some other widget for example if you have multiple fragments that want to show one after the other use viewpager or you can use horizontalscrollview. you can create tabs and sync them by viewpager and so on.

Yeah, this can be really hard to figure out. I think a pretty good analogy, from the web application world, might be a servlet and a frame.
An Activity is like a servlet. It is one page in your app's workflow.
A Fragment, on the other hand, is like a block of content. It might appear in several different contexts and it might be served by several different servlets.
In MVC terms, the activity is largely part of the controller. A fragment, on the other hand, is more like a view include.
Much of the time, those two concepts align. A page in the workflow frequently contains exactly a single block of content. As you have, wisely, noticed, though, when you get more screen real estate (on a tablet), it is entirely possible that a single activity will display more than one fragment.
A single activity, on a tablet, might show, for instance, both a list of selectable items, and the details for the currently selected item in that list. When you have less space on the screen, though, those two things would be displayed as separate workflow items. Clicking on an item in the list invokes an entirely new activity.
The content is constant. The workflow changes.
Most modern applications will use a Fragment to display Activity content. It makes the application more flexible and easier to adapt to wildly different screens.

Android Fragments or Layouts - advice needed

I am developing an application which should display a number of tiles on the first page. Tiles are generated dynamically from json, each should allocate itself according to size specified in json and should take as much screen as required. Each tile represents short summary of information. The requirement is that when tile is pressed user is redirected to another page which provides more detailed info (like a form) which takes the whole page. User then should be able to go back to previous page and choose another tile if needed or go back to the first one. I don't know in advance how many tiles there will be and what are their components, so everything is dynamic. There is also a possibility that small tiles(with different info) can be required to be drawn on detailed view.
At the moment I am on the stage where all small tiles are displayed on the first page and I need to find the best way to display detailed view and allow user to navigate easily and quickly. Each tile extends RelativeLayout because of absolute positioning of components inside. I am considering switching tiles from Layout to Fragments because they seem to be providing flexibility required and many articles and tutorials I search refer to them. In this case when user presses the tile fragment, all existing tiles would be replaced with required detail fragment. Pressing back button would replace detail fragment with previous smaller ones on the screen (would it be display all of them or only one?).
Another option I am considering is to leave layouts and on tile press redirect user to a separate Activity with detail view. In this case navigating back seems to be destroying activity and it will need to be redrawn again if user wants to come back to it (redraw is not desirable).
My question is what is better for performance. Each tile as well as detail view might have some images in it and full page will take time to load. But figuring out how to handle this with Fragments programmatically might take a while and the last thing I want to find is that Fragments are not suitable. Maybe you have other ideas for scenario described? Any good tutorials/articles where Fragments are created and managed programmatically completely(no XML).
I am relatively new to Android and completely lost now.
Edit:
Thanks everyone for your advice. I can't choose the best answer at this point. I have to do some more research and learning now. Will do that later.

Fragment should be the best way to go. because filling details in a fragment dynamically is easy. will help check some codes i have written that could solve this

Fragments are a new style in Android for creating GUIs, they should not be compared with simple Activity + xml layout's in performance terms. Fragments were created to make it easier to build complicated GUIs, on both phones and tablets. You can create low performance GUI using both methods.
From your description I suppose its best to create two fragments, and wire them in Master Detail pattern. Master will be your json list with short summaries, and detail will be your additional data fragment. You can still put both fragments in separate activities, and show detail fragment from master one (master actitity will get hidden) - this makes sense on small screen devices. But you can show both fragments on one screen on tablets. See 'Master Detail Flow Template', http://developer.android.com/tools/projects/templates.html.
So fragments gives you a lot of flexibility to modify your UI, without huge code rewrites.
Some new widgets like ViewPager will work only with fragments, so if you want to use it you better invest time in learning them.

From what you have described above you do not need Fragments to do this. On your main page you can use a GridView to display your tiles. You could create two other Activities. One called TileActivity which will open each time a tile is pressed. Then you could create a PopulateActivity which would populate the TileActivity with the relevant information depending on which Tile was pressed. In terms of performance instead of closing the TileActivity to go back to the main page you could use Intent Flags so that the TileActivity isn't closed it is just added to the stack and then restarted instead of recreated each time its called.

How to switch between different activities like tabs in android?

I need to develop an application which contain these tabs shown in the image. Each tab contain a form which will be filled by the user.User can switch to any tab.
User click Activity1, Activity 1 gets displayed and user enters some data; then user press Activity 2, activity 2 gets displayed, user press Activity1 again, Activity 1 gets displayed with the data entered by the user(not the blank activity).
At the end when user click "Save" I need to get all the data from these activities and save it somewhere.
I have worked a lot in java but new to android, I am stuck in developing the UI for this scenario. However I have done this many times in iOS.
Anybody please share your experience of developing such UI.
Thanks,

Fragments will be more suitable for this scenario, the benefit are
They are light weight and faster
Managed automatically by the FragmentManager.
Data Sharing between Fragments is smoother and simpler than it is for Activities
They don't complicate the Architecture of the Application
You can have as many Fragments as you want in you Activity. Following two links can be useful for you.
A similar Thread
A Good Tutorial
Another good tutorial
If even after that you decide to use Activities, You need to think

Activities, Views and Dialogs in Android. Proper application structure for game

I was in the midsts of tinkering in android with the goal of trying to make this small exploration game. I actually got pretty far so far: a nice sprite system, a title screen with a main menu that is all in game code (no UI buttons or anything) that launch various activities. An activity that loads this cool map view, that when clicked on will load up another view of a more detailed "zoomed in" action part of a map. It all works pretty well but now I am left wondering how well I am going about this.
(What happens to a view when you instantiate and then move the set the context to a new view? I am guessing as long as the activity is alive all the instantiations of various views that an activity uses are still good? And in an activities onPause is when id have to save the data thats changed in these views to persist the state in the event the user quits the game etc.. ?)
I have three menu options at the start of the game. The main one is:
New Game
The new game, I launch my main map
activity that can launch three views:
First two are a loading screen for
the second, a map screen.
Third view is a more detailed action
orientated part that uses this sprite
engine I developed.
It all works pretty good as in the map view you click on a cell it tells the Calling Activity through a listener to start the detailed action view, and passes in the ID of the cell (so it knows what objects to load in the detailed view based on the cell clicked in second view). (This took me awhile to figure out but someone helped here on another question to get this.) Reference that helped me on this part here. I also used the various information here on ViewSwitcher.
I got even a yes no dialog box in the second view that asks if they really wanna goto that cell when they click on it, a yes tells the calling activity to set the new view. What helped me to get this working was this reference here. I also had to fiddle with the calls to getContext and that, I am still not 100% sure what getResources and getContext do for me.
So is it bad practice to call and load a dialog from a view? If it is, then I don't understand how if I have an event in the view that needs to pop up a dialog how I do that? Call back to the activity and let the activity handle it the dialog response and then call a method on the view for the response?
So far all this works great, I did have a bit to learn about threads too. I spawn a different thread for my MenuView (handles the detection of button clicks and responses), my CellMap view which handles the cool big map that users can click on to see the indepth view which is my SystemView view.
So basically the activity call list is like this:
Home.Activity -> ScrollMap.activity which listens to CellMap wher ethe Yes/No dialog apperas (in the view of CellMap) and if the answer is yes to the question, then the onTouchEvent starts up the SystemView view using
private CellMap.MapClickedListener onTouchEvent=
new CellMap.MapClickedListener() {
#Override
public void onMapClick(int id) {
setContentView(new SolarSystem(theContext,id));
}
};
To help anyone else, that listener had to be defined in my CellMap class. Then in the ScrollMap activity when I am about to start the CellMap I just call a method to CellMap sets the map click listener. So far this is the only way I have been able to get data from a dialog (in this case a it was clicked so set the new view) back to the calling activity. Is this proper practice?
Now my biggest question is, I have a playerObject class I want to initialize on new game event (I know how to detect that push) and that then is available to any view in any activity for the life time of the cycle. So far the game activity has just two (3 if you count the loading progress bar) views. I want to get the players name, is that another activity or view? I cannot find a decent tutorial of just how to make a simple input dialogg box that would return a string.
How do i go about passing this stuff around? After I get the players name from wherever that edit box is to be loaded, I want to set the players name in the class and pass that class instance off to another view or activity so they may get at that data. Everything I have searched on this seemed like overkill or not the right way. Whats the best way to pass this "playerClass" around so that I can access it from other views (to say display the players name in every view).
I also have my Home Activity that waits for an onClick on 3 buttons, it then launches their activity that shows the view. I realize a continue game and new game are the same activity and will just change in data loaded off the drive to restore a save game. When the new game button is clicked I would love to get the players name they want to use and of course set the member of the playerClass to this name so it persists.
Where do I call (an edit dialog is it?) the edit dialog from? (more over how do I build one that can take an okay button and input from keyboard etc). Id also like to make it pretty, maybe I could have a simple view that has one edit box in it and a nice image background (though I haven't figured out how to place the edit boxes to fit nicely matching a background i draw for it. I guess id like an edit dialog I can skin to look how i want it to and fit the look of the game).
I am actually kinda happy what I got so far its looking not to bad, just not sure about some specifics like getting user input for a name of the player. Storing that information and passing it then to other activities and views.
Is it better to have one GameMain activity, and a ton of views:
Map view
Character sheet view
inventory view etc etc?
Or Should there be diff activities in there somewhere as well?

You've written a lot here, so I'm go gonna go ahead and answer the questions I think you're asking.
First, how can one share information between activities and views? If you're just sharing it between views in a single activity, store it in the instance of the Activity subclass.
Sharing between activities requires a little bit more. Instead of using an instance of the default Application class, you can create a subclass of Application and use that instead. Put your data in fields of that subclass. To tell your app to use your subclass, modify the app manifest like so:
<application
....
android:name=".YourAppClassNameHere">
....
</application>
As for getting user input, the simple answer is use the built-in EditText view. since you seem to want to give your game a more "custom" style, though, you may need to go about creating your own editable textbox. That and buttons should allow for most sorts of basic user input.
Now, good practice vis-a-vis activities and views. I'm not aware of a standard for this, but when designing I generally try to think of activities as more conceptually separate elements, whereas views are conceptually interwoven. the line between the two is dependent, in part, on the scope of the app; an app with a narrow focus can afford to break more actions down into different activities than can one with a much broader focus.
Your "GameMain" example is a bit on the fence, but I think you've made the right choice: the activity is "playing the game," as opposed to a menu or high-scores table, and the views present different aspects of the game being played.