So im wondering how I can change what is displayed on the phone screen without the need for creating a new activity each time I wish to do so.
For example in a simple game im trying to make: there will be a small row of buttons (inventory, stats, save, options, etc). When I press one of these buttons, how can I change the view within the same activity to show the appropriate data without having to create an entirely new task, if possible.
Two possibilities here depending on what you're really trying to accomplish.
1: If this is just another xml layout you want to display I would suggest using fragments.
http://developer.android.com/guide/components/fragments.html
2: If this is graphical ( often true with a game ) you will need to extend SurfaceView and
implement a drawing thread. http://developer.android.com/reference/android/view/SurfaceView.html
( There are multiple examples of how to do this if you google for SurfaceView example ).
It's not a good practice but if it's simple enough you can just use view.SetVisibility(View.Gone) to views you wish to hide and view.SetVisibility(View.Visible) to the views you wish to show.
Related
I'm trying to create an overlay that is triggered when a button is pressed. This overlay is supposed to allow the user to add their contact and I was wondering how can I use fragments to get this effect like you can see in this mockup.
I am in a dilemna over using fragments is the right choice. My reasoning being that I only need to have it do one task that is adding contacts, and thus I do not need a whole activity.
This is what I have on the main activity right now
I would really appreciate any help on understanding how to make this work.
You can use a DialogFragment.
It behaves like a normal Fragment for the most part. Here is a guide for a basic implementation https://guides.codepath.com/android/using-dialogfragment
They appear automatically in the center of the screen. To get it a bit lower like in your mockup you can change where it is in the window. Here is an answer showing such Position of DialogFragment in Android
I want to make a recipes app, the basic layout is the same for all the recipes the only thing that changes are the images, times and ingredients.
The problem is, I could make 40 activities, one for each recipe and performance wouldn't be a problem because the user is only interacting with one activity at the time. However, writing the same code and going on a copy paste spree feels wrong.
I would have to repeat the same code over 40 activities and it would work (I guess), but it would be much easier to create one activity with the functionalities I want like a timer and the layout and in some way make smaller files that insert the data for the selected recipe in that "pre-made template".
There's must be a way of doing it, although I'm not experienced enough
Here is an example layout
It is usually good practice to have a base activity that implements all the code common to several activities then those activities can simply inherit from the base activity like this public class ChildActivity extends BaseActivity.
This will allow you to call methods that are in the BaseActivity from any of the child activities. You can have a read up on Java Inheritance here and here is a blog post with some examples of using a base activity.
You can create only one activity that will receive the Receipt data as extra using Intent. The layout for this activity should contain an image view(or a recycler view to hold all your images), a recyclerview to show your steps/ingredients and a textview for the time.
Receiving these data from the activity(that one that the user selected which receipt he wants too check) that created this new activity, all you need to do is to setup your layout with this data.
Check this question to get how to pass data between activities
Click here to see how to create recycler views.
I have a workflow with several screens with different questions and answer-options. So there is a question on screen 1 and the user makes his choise -> the user hits the continue button -> screen 2 opens with another question -> user makes his choice and continues -> screen 3 opens etc...
But actually I'm not sure which is the best way to implement this behavior in consideration of a good maintainability and clearness. I think they are at least three options:
Every screen gets its own activity and layout file and I pass the choosen data trough intents.
1 Activity and different fragments, each fragment has its own layout. If the continue button is pressed, the fragment will be replaced with the next fragment.
1 Activity and different layout files. Just the layout gets replaced and everything else is handled in the activity.
Actually I already started implementing with option 2.) but I don't know if this is not "too much".
The Android API guidelines say that you should use Fragments for multipane UI and for reusability. But actually I don't want to build a multipane UI in this case and the fragments are not reused. So maybe 3.) is the way to go? Or even 1.)?
I would choose your option # 3. The reasons are:
Activity takes some memory compared to fragment or layouts. The interface between activities and fragments is a bit awkward, though I got used to it. I don't recommend it for your case.
I like fragments. However if all the fragments are similar in looks/feel, then why take the computer time for hiding/showing or replacing them. The reason for fragments is stated in Google web page like at Building a Flexible UI. I don't think you need a flexible UI as said in Google's intention.
I would suggest one Activity, at least one Fragment for all the questions/answers. You simply use one layout to change text/content. If the UI is different, then replace the layout with another. It's quite normal for an Android app to have so many different layouts anyway.
Android takes some memory to load layouts but it's quite fast and efficient.
For option 3 design:
You can use the inflate() method to load a certain layout and to replace one. A good example at SO link # Android layout replacing a view with another view on run time
I need some advice for those who are experienced making Android applications. What I would really like to have, for my application's appearance: at the top, a title-bar which is a ImageView (content is a png), and at the bottom a series of custom buttons which make up a tab-bar like thing. In between the title and the tab-bar is the Content, which may be anything... (most likely buttons)
I have been doing this by making a RelativeLayout which specifies LeftMargin and UpperMargin for x,y coordinates--
Currently all of my activities are inheriting a custom MyActivity class, which rebuilds the title and the tab-bar at the time of onCreate. This seems bad to me!
PART1)
---A solution to Persistent data
Since the "tab-bar" and the title are persistent no matter what screen you're on during this application's run-time, it makes the most sense to store them somewhere... How should I do this? Make a singleton object that the Activity's ask for?
I thought a little about the singleton object, and I'm not even sure what I would store, since the Views that are on displayed during Activity A have activity A as context, and not Activity B.
PART2)
---Animation Aesthetics
I would really like to have the "Content" (the view in the middle between title and tabbar) slide out to the left, and the new content slide in from the right. I.e, I'd like the tab-bar and the title to remain fixed while the "activities" change. is this at all possible? What should I do to achieve it?
one idea I had, was to make all of the program in one activity! I would create an animation for the Custom View in the middle, and I would override the "back" button to navigate correctly to the previous Custom View. Is that a horrible idea?
Anyone have any advice?
Read http://developer.android.com/design. Most of the design principles can be applied to apps that run on legacy releases; it's not just limited to Honeycomb and Ice Cream Sandwich. Do consider the Action Bar and Dashboard design patterns.
I don't really recommend using just one Activity -- generally, an Activity should be a separate, encapsulated, pretty well defined chunk of functionality that can execute independently of other Activities.
To avoid duplication of your UI, consider reusing XML layouts.
To avoid duplication of your logic, consider using Fragments. You should be able to mix and match them in your activities.
To achieve the animation you describe, consider implementing a ViewPager.
Using the ActionBarCompat sample app and Android Support Library, you can enjoy modern goodies like Action Bar, fragments, tabs, and horizontal sliding transitions on devices running Android all the way back to Donut (1.6).
I am working on an Android project where a group of buttons needs to show on the bottom of every screen (activity) in the application. The group of buttons are basically a navigation bar. I want to know the best way to do this without creating new buttons for every activity. I have been around programming (C++/C#) for many years but am pretty new to Android and Java so if someone can point me in a general direction, it would be appreciated.
Thanks.
I bet you need to use "include" tag for xml layouts. It's the best when you need to reuse some UI components. See http://www.curious-creature.org/2009/02/25/android-layout-trick-2-include-to-reuse/ for the examples and description.
To elaborate on Konstantin's answer, after you've used include, you'll need to bind actions to these buttons.
If the buttons should have the same action regardless of the activity they are in, use the include tag to create their layout and then create a parent NavigationActivity (or whatever else you want to call it) class from which all your other activites will inherits.
In the parent NavigationActivity class' onCreate method, you can set up the onClickListener (and other needed stuff) for the buttons.