I have developed some apps for Android, and this questions stays always:
How should I structure my UI? Should I launch activity after activity and leave the phone to make the "back" button, or should I choose more optimized, but more complex to implement, way with switching manually Views and then manually doing the "Back" button functionality?
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Are there design guidelines to help decide if an application with multiple views should be designed with multiple activities or just one activity and control the back button itself.
I've tried both. My most complex applications using one activity per screen. However, now that I'm successfully written an app with just one activity and handling the back button myself, I don't see any compelling reason to use multiple activities. The one activity application is much simpler and more straightforward.
What advantages of multiple activities am I missing?
I'm working on an application using xml layouts.
I wish to know which is better:
1. Use few activities and change its contentview
2. Use an activity for each 'view' needed
If both works, in which case which option would be better?
I have an application using ListView inside Tabs, and I'd like to switch to a separate View(data collection widget) on clicking an item in the List.I'm adding each List's row's children to a ViewFlipper and the items are added at runtime so there is no definite number of views. As such, i would want to navigate/switch to a particular View in the ViewFlipper.Any pointers?
View 3 Replies View RelatedI start a browser and from the browser,I start a video which occupies only a small part of the screen,say the bottom right corner.
Now the browser will be pushed to the 2nd position in the window order and Video will come to the first position. Is it possible that browser can have the control for active window and receive the key events though the video is the Top Most window.
My situation is the following: I have written one MapActivity class that is able to display a set of places as well as single places. On startup, the application creates an instance of this MapActivity and displays multiple places. If the user clicks on a certain place, then a new Activity is launched that shows the details of the selected place. This activity has a menu item that allows the user to view the place on a map - this causes that a new instance of the MapActivity is created, except that now only this single place is displayed.
The problem now is that if the user navigates back to the first MapActivity (the one that shows multiple places) the tiles won't be loaded anymore + sometimes OutOfMemoryErrors are encountered. According to the Android JavaDocs, it is only possible to have one MapActivity per process. However, I don't want to define my MapActivity as a singleInstance/singleTask, since the user should always be able to navigate back to the first MapActivity that shows multiple places. I have seen that the Google Places app (which has come with Google Map 4.4) for Android uses multiple MapActivity instances. How is this possible?
I have the following XML code:.................
The idea is to change the views, whenever I press one of the radio buttons. When I press a button the first time everything works out fine, but the second time I press a button, I get an IllegalStateException, and I can't quite see why I'm getting this.
Also, the Activity seems to set all my global variables to null, which is why I have to create them every time I switch from portrait to landscape or vice versa. So I would like to know if there is a way I can save my views in the Bundle, or any other way in which I can permanently save my views, so I don't have to add or create them every time, I flip the phone. And whenever I flip the phone, it seems that it rereads the main XML file, causing the RadioGroup to be set to 2D even if the 3D button is checked. This is because I've said the 2D button to be checked from when the app is first created, but I would like to also save the state of that RadioGroup.
how to call BarCodeScanner, and return the value to a field.so now, i have a toast that says "successful scan" and then i want to pass the result to a new activity. when i comment out my intent, everything works (minus the passing of data/switching of screen, obviously) but when i run my project as is, it FC's no errors reported by eclipse in code or xml. any insights?
View 2 Replies View RelatedI'm planning to develop and app that presents the users with several different screens (of different information).
Was wondering what would be the best way to implement this?
Is it better to have separate XML layouts and an activity to display and allow the user to interact with each screen of data?
OR would handling all of these in the same activity be more efficient (and dynamically load / unload each layout)?
I am working on an Android app that has multiple screens the user will need to navigate between and I am curious what the best practices are when switching between those screens. I am torn between creating a new Activity for each screen and simply changing the view (setContentView(R.layout.whatever)). The screens all share at least some variable values so I'm leaning toward changing views and using class level variables, but I'm worried a single activity could become very large and confusing with logic for multiple screens in a single file. I'd like to keep the code clean and separated, but I also don't want to be passing several variables around between views if that isn't needed.Being new to Android development, I'm hoping some more experienced members of the community could share their thoughts and let me know how best to handle it
View 2 Replies View RelatedOn my application I'm developing, the main.xml layout (the default layout of my app) has a few buttons that have been assigned onClickListeners (not the implementation way). One of those buttons I want to have the ability to take you to another view. On the other view (preview.xml), there's another button that takes you back to the main.xml view. I've used setContentView in the onClickListeners of those buttons and this works fine so far, but after you click the button that takes you back to main.xml, the buttons on main.xml have lost their onClick functionalities. How can I get this to work right? I presume using setContentView isn't the right way to do this?
View 2 Replies View RelatedI've got a activity showing the user a list of songs to play, and when he opens a song I launch an activity which embed a player.
My problem is that when i finish playing i call "this.finish()", but when the user reopen the player, the "onCreate" is launched and it seems that the GUI is building itself "again".
I've tried to not call "this.finish()" and call the Activity.startActivity on the father, but with this way, when I clic on the "back" button on the emulator, I get all the players playing in the same time (they still exist).
So my question, is there a way to make an activity "a singleton" or to freeze it to be retrieved later (It can't be able to retrieve it with "back" button) or a way to cache all the constructions so to not have to do it again ?
I am developing a Music Player and I have a view flipper to control all the artist view, album view, so on and so forth. What I am doing now is that I have list view in each view of the view flipper. However, I do not want to put all my codes inside one activity but rather, to have different activities for each view. Is that possible to implement?
View 1 Replies View RelatedI've got a basic list activity with a few images that when you select one starts a new activity with a SurfaceView (based on the Lunar Lander sample). Some times the screen is just blank, from some debugging I can see that the background .png is being loaded and doDraw() is being called by the activity doesn't display anything for anything from 4 to 20 seconds. Other times the game activity is loaded just fine. I assumed it was some kind of garbage collection problem but I can't see anything in LogCat and the second activity is actually loaded, just not displayed for some reason.
View 2 Replies View RelatedTrying to understand the Android framework model. I have an application that needs to have several threads running. On thread gets GPS fixes, another picks up GPS fixes and pushes them to server, and yet another occasionally polls a server for dispatched orders. Some of these threads update status Views as well.
Since I am new to Android, the application framework model hasn't clicked for me. Where are these threads started? Right now I start the threads in the initial Activity, but if I understand it right, once that Activity goes invisible it is stopped. Furthermore, I have to track GPS and network statistics so that I can have a View which may (or may not) be the active View.
I am attempting to learn how to develop on the Android platform but do not quite understand the relationship between Activities and Views, because according to the documentation an Activity is almost always linked to a UI object that the user can interact with, but if this is the case where does the whole idea of Views come in?
View 1 Replies View RelatedI have a 3 nested ViewFlippers which seem to be working ok except that when I change the screen orientation the view flip back to the first one of my views, giving the user the impression it went back a few steps.I am a bit stumped as to what to do and was hoping someone had some experience with this.
View 3 Replies View RelatedI'm starting on Android and got a beginner question on switching between multiple activities. I understand i can go between two activities by invoking an intent and then returning with setResult(). What I want to know is how to jump between multiple activities. Specifically I want to learn about the process life-cycle. I understand how every activity is started ar onCreated(), but I'm not sure how to implement onResume() or onRestart() when I want to come back. So basically I have 3 activities: Activity1, Activity2 and Anctivity3. I start with Activity1 and then invoke Activity2 with an Intent, and Activity2 invokes Activity3. Using buttons. Now I want to come back to Activity1 from Activity3. I do the same thing here too. Make an Intent and call startActivity(Activity1_Intent). But it gives a runtime error.I think I need to implement OnResume() or onRestart(), but I'm not sure how to do this. In onCreate() I make a gridView, so when I come back, do I need to make that gridView again? If anybody could give a small explanation of refer to a tutorial it would be great.
View 1 Replies View RelatedDoes switching activities in Android start a fresh JVM? It seems like each activity is meant to run as its own "main" method. If I have a singleton (via Guice, not an actual singleton in this case) should I expect to be re-creating it every time I switch activities?
View 1 Replies View RelatedCurrently I have a TabHost implemented with 3 tabs each containing a separate activity. My question is how do I switch between tabs from within one of the activities that is located inside the tab host. ie say i have a button inside one of the tabs[tab 1], when i click on this button it should switch to another tab[tab 2]. To understand my problem click on the link below, http://stackoverflow.com/questions/2541802/android-switch-tabs-from-w.
View 3 Replies View RelatedI posted a StackOverflow question here (http://stackoverflow.com/ questions/4226898/dismiss-android-popupwindow-when-switching-to-a-new- tab-in-tab activity/4227034#4227034) but it didn't get any responses. Basically, how can one dismiss a PopupWindow when changing to a different TabActivity? The onPause() method in my TabActivity causes the app to force close.
View 2 Replies View RelatedI'm currently developing an Android-app, in which I have already implemented an Slidingmenu (jfeinstein10's library). As above-views I have several activities I'd like to switch between with the menu-items in my Slidingmenu. For the most part, these activities consist of two fragments, a list and a content-view. In landscape-mode both are displayed, in portrait-mode only the list. Currently I'm switching between these activities with intents, which is not a very pretty "solution". How should I implement this?
View 1 Replies View Relatedi am using canvas for 2D graphics using Views, Now i have to switch from one canvas to another Canvas.
View 1 Replies View RelatedI've been programming in Android for two years now and just joined an Android project where they are using a TabActivity to host multiple Activities. It's unclear why this is better than rewriting the TabActivity to simply use Views instead.
TabActivity extends ActivityGroup which means TabActivity can host both Activities and Views. But what's the use of this capability? I was under the impression that Activities should be treated as individual screens of an application.
In short, what is an example use case where it's recommended that TabActivity should host multiple Activities rather than multiple Views?
I am using a TabActivity (Main) with 3 TabSpecs
I am using Intents for the content of the 3 Tabs
TabA, TabB, TabC for example.
All these tab activities use common data that is stored in SharedPreferences
In the Main TabActivity I have an options menu which has a refresh option.
CODE:.............
This refresh uses an AsyncTask (updateCommonDataFromWeb) to reload the common data from the web.
I need a way to tell the 3 tab activities to refresh their views and rebuild their content from the newly downloaded data.
When the tab activities are first created they load the data from SharedPreferences like so:
CODE:..............
I thought about making a common method on each of the tab activities
like.... reloadViewData()
I thought maybe I could use the activity manager from the Main TabActivity to get the activity of the current tab like so:
CODE:.............
Unfortunately i cant get this approach to work, whilst activity is the correct instance its an Activity instead of a TabA,TabB or TabC
Maybe i've completely taken the wrong approach to the whole thing.
I have also read alot about not using Activities for tab content instead using views.
However I dont know what view to use to replace my <RelativeLayout /> as i cant use my R.layout.* as views.
I am working on a graphics application in Android. I have a question regarding MULTIPLE SURFACE VIEWS. Can I be rendering multiple surface views at the same time. Initially, when I had two surface views in the same activity, it didn't seem to work, as it used to show only one at any time. But, with one surface view attached to one activity, is there any way I can keep the background activity's Surface View alive so that both the surfaces get rendered together?
View 2 Replies View Relatedwhat would be the outcome of using findViewById when multiple child views have the same ID lets say for example when using a layout to dynamically produce multiples of the same control?
View 4 Replies View RelatedI have a ListView that could have 4 different views for a row depending on the data for the row. I have the ListView working correctly overriding getViewTypeCount and getItemViewTYpe. I originally was trying to dynamiclly update the view type count as new views were inflated by forcing calls to getViewTypeCount because it was possible that maybe one or two views may be all that would be needed. The app never functioned correctly crashing after there was more than one view added. The problem was fixed by setting getViewTypeCount to always return 4. I noticed getViewTypeCount is automatically called on app start-up and never called again unless a force call is made. So I'm just curious if this can be changed dynamically or do you need to know the number of max views you can possibly have and override getViewTypeCount to return that max value.
View 1 Replies View RelatedI tried to add these views to list view using this kind of factory but everytime I try and add the view to a ListActivity, it comes up with nothing. What am I doing wrong?
View 3 Replies View RelatedI have a very simple game that consists of only one activity, and I want to add a title screen.If the title screen is another activity, what changes do I need to make to my manifest file to make the title screen open first?The gameplay activity is called Leeder, and the title screen activity is called LeederTitleScreen.
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