java android view structure - java

Just a simple maybe stupid question.
Is it ok to use multiple activities at once in an android application using an Inflater? I want to have multiple views on my screen without losing the previous view. For example, a user clicks on a button and a information screen shows up. Start Intent would convert the whole screen to the information screen activity.
Using an Inflater works but I'm just wondering if its the right way to display multiple views. Thanks in advance.

You should be using Fragments for this. Each fragment has a view/layout and you can move them in & out of your main view as you require. There are many tutorials

You can set the visibility of the views, e.g.:
Button b = (Button)findViewById(R.id.button);
b.setVisibility(View.GONE);

Related

How to Show Custom View (FAB) On All Screen in Android

I want to show my custom floating button on all screen in my app without putting it in each activity.
Do we have some Global Activity like put a code once will show the Custom View all screen and hide/remove when app killed
I tried lot of things like Screen Overlay display over all apps
Please check code here - How to display custom view on all screen in android from my library
I've never tried to do it the Java/Kotlin way. But have you considered using Fragments?
You can declare xml layout and code for one Activity with a FrameLayout container and an FAB. The container holds all your screens and they switch between each other in the container. The FAB is on top and therefore will be displayed no matter the screen.
The Activity has a reference to any screen that might be displayed in it, so the FAB can behave accordingly.
Not sure if this helps. Perhaps if I see some pictures, I could suggest better.
Related Read:
Creating a fragment: here
Fragment Transactions: here

I don't understand how to organise my fragments

I have realised an NFC reader application
So i have 3 activities :
MainActivity, which is an activity who contains a Button. If button is clicked, the scan is activated and the user can put his NFC tag against the device to detect it.
WebActivity, who is launched if the NFC tag contains and URL (and open a WebView) or if the user want to launch WebActivity by himself
HistoryActivity, who gonna contains a list of every scans.
Now, I would like to swipe activity with a finger gesture. according to my research on Internet. I need fragments and ViewPager.
But every example that I saw is bases on ONE activity and multiple fragments.
But in my case, I have to create 3 fragments (one per activity), right ?
And I really don't know how to manage my fragment. I mean, what to put inside ?
All I want to do is create a transition/animation while changing activity... That's crazy
This is too broad of a question but hopefully my answer will steer you in right direction.
You should definitely go with single activity/multiple fragments model. Aside of recommendations by Google, you could use navigation components, deep linking much easier then without single activity.
Yes you should be using ViewPager for the purpose (and likely your implementation of FragmentPagerAdapter as well) however I do not understand what kind of swiping will you be doing
Reading your setup, I would suggest to use bottom view with 2 items (good example is here https://github.com/android/architecture-components-samples/tree/master/NavigationAdvancedSample/app/src/main/java/com/example/android/navigationadvancedsample). 2nd one would show history, first one would offer a button that activates your action, and then displays fragment with your WebView.
As a side effect of such implementation, you'd be able to go back from 2nd bottom view item to whatever first one holds - by pressing system back button - which I think is nice touch.
UPDATE to "swiping takes place anytime. " comment:
You could have single activity, ViewPager with 2 fragments. First fragment would display a button, 2nd fragment would display a history. You could freely swipe between them, as you want to. However to me it does not make sense to put WebView screen into this. WebView screen is result of action (NFC detection) and it should probably display as full screen, without any chance of swiping between main/history and itself. Hope it helps or I'm missing some important piece of info you did not share.

Android: How to open a new full screen fragment from a fragment

I would like to open a new full screen view (layout) from a fragment without have to create a new activity.
I know how to do it creating a new activity but I read you better "always" use multiple fragments, not multiple activities for your full project so I am following that "rule"
You can check the images attached to explain the situation I would like to reproduce. As you can see, from a fragment with a listview, it open a new full screen view. Tapping the back button in the action back, you go back to the main with navigation, toolbar and the list.
I am using xamarin but a suggestion using java will work too for me. I just need to understand the concept of how to do this and what kind of controls do they used.
Thanks in advance.

stack activity in android

Hi i am working with android , and i have a problem with the activity stack. As i know, when someone uses the back button, reload the back activity. But in the case i have many layouts shown from one activity, how can i go back to them.
Here is the deal, i am using a listview filled with categories, and when i press an item, i reuse the activity and the layout, to show its subcategories. So what i need is to came back no to the back activity, not to the back layout, but to the back "state".
Well, the idea is simple, first i show all the categories with no parent, then when i pressed an item, i show its subcategories.
The easiest way is creating two Activities - for categories and for subcategories. If you try to implement all the logic in a single Activity you won't earn nothing and just end up totally confused. Using Activities simplifies things a lot just because it handles problems such as yours. Hope this helps.
Check out Fragments, they are the stepping stone between a view and an activity. An activity can have multiple fragments and will manage their back stack (if you tell it to).
http://developer.android.com/guide/components/fragments.html
You'll have to use the support library to used them on pre honeycomb devices.

View different images depending on what item in my list view I click

I'm fairly new to Android programming and I've got this project I need to finish and I'm currently stuck.
I've got a standard listview in a Menu class with an array containing around 20 different elements. So what I want to do is load images in an imageview depending on which item in the listview I click, and since I'm a beginner the only idea I had was to make a new activity for each imageview which seems like a pretty bad way to do it since I'd need about 20-30 new activities..
To sum things up what I want is:
Code for making ONE activity that will display a different image depending on which item in the listview I click, probably pretty basic coding I want as simple solution as possible.
If possible I'm also looking for a solution that includes an SQLite database that stores the URL of an image and then display it in a single activity, also depending on which item I press in my current listview.
(I hope you understand my needs, and if you need I can also post my current code for the Menu class if it helps you help me) Or you can just show me a different way to make this work, I appreciate every answer! Thanks in advance!
NOTE
And please keep in mind, I'm a noob at Java and Android so keep it rather simple or at least explain what you do.
When you click on a list item, display the image in another view in the same layout, unless you want the image to take up the entire screen real estate. If you want it in the entire screen, go to a new Activity by sending the activity an Intent.
Activities are the "controller" of your application. They interact with the visible UI and the input from the user. You don't need a separate activity for each image, just an activity that's associated with a "place" in the UI (an ImageView) where you'll display the image.
I'd start by adding the images as resources under res/drawable before going on to databases.
You are going to have to do most of this yourself. There really isn't any substitute for taking the time to learn Java and Android. There are several tutorials and Android University classes under the Resources tab in the Developers Guide; I suggest you do all of them.

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