I have a tabbased application. On one of my tabs I have a listview with productcells. When the user taps the row a new activity is launched. Is it possible to start the new activity as normal but without "losing" the tabbar at the bottom. Because now my tabbar is gone when I start the new activity. Much like the navigation hierachy on iOS?
This is what you are looking for:
http://blog.henriklarsentoft.com/2010/07/android-tabactivity-nested-activities/
It basically explains how to use ActivityGroup to achieve that effect. I usually don't recommend this approach, not only because sometimes gets a PITA to handle but because it too iPhone-like. Remember, you are developing for Android.
Edit: with regards to Mur's comment... it's not a matter of fanaticism (I even own an iPhone). So what's wrong with doing Android apps in the iPhone way? Basically, the Android OS is not designed to be used in that way. For instance, the nested tabs: using ActivityGroup forces you to handle the back button manually, the activities themselves don't work as they should (what you do with ActivityGroup is getting the Activities' Views and play with them), you have to create public static non-final objects to handle simple things like showing a dialog, etc.
Just saying.
Related
My application basically has one main activity. Within it there are three tabs, each with a fragment. Something similar to the layout of whatsapp.
To add more functionality to the application, I saw that the NavigationDrawer would be a good option. But because of my application running with a main activity with children fragments, I wonder if it would be a bad practice loading activities and not fragments, when the User clicking on any item NavigationDrawer.
Or does the best meneira would turn my MainActivity in a fragment? It would give me a great job ..
I would like to suggestions =)
You can use the NavigationDrawer to open new activities. Basically just make each of the Activities have the same-looking Drawer and the user experience will be same as if you were replacing Fragments.
However, I would discourage this. I have been working with apps that mixed Fragments and Activities for the NavigationDrawer and the outcome was problematic, especially when it came to backtracking and saving state. It did work, but required hackfixing and some illogical code.
The best practice for the NavigationDrawer is to have one "container" activity which does little more that just exchanging Fragments in a FrameLayout it holds. The rest of the logic would be in the Fragments. This way the app is easily extendable and the backstack is handled by the platform.
I prefer Fragments but there is no problem to open new Activities. Instagram does something similar. It has tabs (I know that you want to use NavigationDrawer, but this is just a example), and one on these tabs open a new Activity, with the X button to close the Activity.
Instagram Main Activity:
New Activity with close button:
The Series Guide Android application does exactly the same. It opens Activities from the Navigation Drawer. Such Activities extend the BaseNavDrawerActivity. The Activity's start and exit animations are custom to make the transition looking smoother.
I would recommend this approach since it's much more easier to manage Activities' back stack than Fragments'.
Proceed happily with opening activity as well. Make sure you put the back button on the opened activity so that user would have clear idea that which screen is the primary.
But wait..
If you are worried about whether you are following the standards (industry) or not then read below:
If all your activity has the equal importance for users (including the tabbed one) then recommended way is to use the fragments and on the other side if you don't want people to get distracted by navigation drawer icon or tabs then better to open a new activity with just a back button on top..
I hope it would give you idea how to proceed..
Just a disclaimer, I am pretty new to Android and slowly working through tutorials. Most tutorials dont talk about fragments at all in the beginning, but Android-studio by default sets up one for you.
I've read some of the past questions and the dev blog related to fragments and activities and they were helpful in giving me an idea as to the advantages of using fragments.
I am still a bit confused on when one would use a new activity in an app, it seems to me like everything could be accomplished with fragments and a single activity.
Lets say an app has multiple screens, do you implement that as one activity with multiple fragments, or multiple activities with one fragment each to them.
This image makes sense to me and demonstrates the power of fragments, but why on the handsets example is two activities required?
Another add-on question, should everything moving forward be done in a fragment?
Thank you and sorry if these questions didnt really make sense.
An Activity should be the host for a collection of related Fragments. For instance, you might have something like:
Base Activity extends FragmentActivity
LoginActivity extends BaseActivity
-- LoginFragment
-- LoginErrorFragment
-- LoginSignUpFragment
SettingsActivity extends BaseActivity
-- SettingsGeneralFragment
-- SettingsAdvancedFragment
If you try to move all of your logic into a single Activity, it's going to get unmaintainable very quickly. Another good practice is to have a base Activity which all of your Activities extend; since if you suddenly find that there's some functionality you want to provide to all activities, you can just add it to the base class.
Everything said above in both regards are absolutely correct. I would just like to add few points to them.
When thinking about fragments please keep in mind that they are a part of an Activity, which like any other view can be added, modified and replaced dynamically. For example, while using ActionBar's and Navigation Drawers fragments become more handy and flexible. Similar things stands true for ViewPager etc.
Fragments also cater to larger screen sizes in a much better way than the traditional Activity approach. Imagine the users experience then when for every action performed a new screen would replace the Phone/ Tablet against now when all the actions and their performed events lie on the same screen.
One more thing which I like about fragments is, we dont have to declare them in the Manifest. :) Most of the time we forget to do that with Activities until the compiler prompts. :) (At least me)
As you said. In simple application you can use only one Activity and just replace fragments. I did it in my apps and it works perfect. Sometimes you just need to start new Activity if you want to follow android design and architecture patterns.
According to your question about images that you posted you can
obtain the same effects using just one Activity and Fragments.
Yes everything moving forward can be done in a Fragment.
I'm looking for the the best way to reproduce, in an Android app, the behavior of the iPhone UiNavigationController within an UITabBarController.
I'm working on this Android app where I have a TabActivity and 4 tabs. I've already gone through a lot of posts regarding the use of activities and tabs and how it's not a good idea to use activities for everything, which seems fair enough. I decided to use one Activity on each tab anyway, since it makes sense in my application.
However, in one of those activities I have a deep navigation tree with more than one branch and up to 12 different views the user can go through.
The problem is: Android controls the navigation through activities inside an app, if you click the back button it will go to the previous one, but if I'm navigating through views, using one Activity, and I click back, it just finishes it. So how can I have a smooth navigation behavior between views in an Activity?
I had implemented this using a TabActivity with FragmentActivity as each tab. Utilizing Fragments API you can organize the code just like you would be using 12 different activities, still using only 1 for each tab in fact. Fragment's framework will handle back key press for you to show previous fragment instead of closing the entire activity.
There are some problems with such approach, for example, there's no MapFragment, but the workarounds can be found here on SOF.
You will need Android Support Package if your minimum SDK version is lower than 3.0.
Well I know very little about UiNavigationViewController, but I guess you want something to navigate between different Views. As you are using TabActivity, every tab should load into a separate Activity.
But since you want to branch it out, using that many Activities is not a perfect solution, neither the ActivityGroup too. The better solution, as per my opinion(I have run into similar problem once) is to have the main or root tabs loads into separate Activity, but for their branches, use the ViewFlipper, which flips the Views. So the whole Layout(Subclass of View) can be flipped.
You may run into some problem while flipping more than two Views (as what people say, though I never had any problem). So in that case you can use layout.setVisibility(View.GONE) to hide the layout and just change it with View.VISIBLE for next view.
And about the concerns of back button, you need to store the last used View or Activity into a variable, and in the override of onBackPressed(), just need to call them.
There might be better solution than this, not that I can remember, but yeah it's the easiest solution I can come up with.
Im making a music player/library app in wich I would like a frame/toolbar on top of all other activities as a header. This frame/toolbar will show information about the current playing track and have some controlls like play, next and stop etc. and be a separate selfsufficiennt activity. Is this possible and if so, how?
You can create an ActivityGroup. This is how TabHost is implemented. So your ActivityGroup would fill the whole window and implement the toolbar. Then you could swap out Activities in the bottom part.
Currently I don't think that making a static top bar it's own activity in the life-cycle idea. However, what you can do is have every activity have the top bar and just re-create the bindings needed for each activity. It gives the idea that a section is static.
Now this breaks down if you start doing animations between the screens. Another solution is to just have a single activity and swap out the views. This allows for animations between screens be custom and only the parts that change need to create the connections they need. The trade off there is that you'll lose any kind of state saving and history that you gain by using an activity orientated approach.
I think you can do something like this on Honeycomb tablets as the fragments idea could be implemented like that but I've never explored it much.
I've recently started developing Android Apps, and whilst the model is making more sense the more I look at it, I cannot do something (nor find any reference material on it) which to me seems quite simple.
I have an activity which has five buttons along the bottom, and a blank View taking up the rest of the screen. I want, upon clicking these buttons, for an activity to be opened in (and confined to) this view. I can get a new activity running without incident, but this opens in a new screen.
If anyone can show me an easy way to launch a (sub/child?) activity within a view which is defined in the parent activity's layout xml file - equally, it could be created in the parent activity - you'd really be doing me a favor!
I'd recommend taking a look at TabHost. The tabhost is an Activity itself, and the sub-views are all Actvities as well.
Here is a good tutorial that'll get you going very quickly. There is a more work to create (optional) icons for the tabs (also describe in the tutorial).
Hope this helps.
Edit* You mentioned buttons being at the bottom of the screen. Take a look at this SO Question
You can achieve that by using an ActivityGroup... here is a simple example which shows how to do it using a TabActivity:
http://web.archive.org/web/20100816175634/http://blog.henriklarsentoft.com/2010/07/android-tabactivity-nested-activities/
Of course, you will have to change the code since you are not using TabActivities. Just take a look at the getLocalActivityManager and getDecorView methods that is what you will be using.