I am a newbie in Android and currently I am designing an application where I have faced a big problem with changing views. I have 3 classes, each one for a different screen. I use a button to change pages but it does not seem to work. Every time I move to the next screen, the variables methods etc of the 2nd screen are located in a different class. Can you please show me the simplest way to do this? Thank you.
Place each screen in different Activity. Start respective activities according to button presses. To pass data between activities use Intent.
Activity Reference
Intent Reference
Simple Example for Activities and Intents
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
For example, I have activityMain which contains the main logic of the Application, but it should be opened from several buttons that stored in other activities, and some activities contains multiple buttons too. And they should call activityMain. So i need to pass different data from db depending on which button called activityMain
Help please, there weren't similar topics at all.
If i Understand your question correctly, you can achieve this functionality with android jetpack navigation component. I add the link of documentation below
Get started with the Navigation component
I am beginner to android..I am started new android project..for supporting
different screen size..in fragment documentation they given to use fragment..but
why cant i use activity in android..if i use activity or fragment..which i should i use in this both..please dont give link of activity or fragment..please anyone answer me..i dont know which to use?...i want about all documentation they given about activity and fragment but i dint understand which to use..below is the link i read about fragment..if i use activity i should do more codings?
https://developer.android.com/guide/components/fragments.html
In fact you can't use a Fragment alone, Fragments are inside the Activity.
One point of using the Fragments for supporting different screen sizes is the ability to implement some views like a "Master/Detail" view.
A Fragment, as its name says, is a part of a bigger controller "the Activity", its reference can be removed and it's cleaner than having a big massive Activity to handle all the states of a view.
So the use case is completely depends on your project and its User Interface. I'd be glad to help you if you give me more information about your project and its design.
I think you will need at least one activity. And then for better handling different device rotations and screen sizes you can use one or more fragments inside this activity.
I try to explain this with an example:
You want to create a nice music player app which should look nice in portrait and landscape mode.
You split your app up into three fragments:
Here you can see how the app looks in portrait mode. The activity shows two fragments: The first fragment only consists of a listview. There the song titles are listed. On the bottom you can see the second fragment, which displays the song title of the current playing song and got a button for pausing the music.
When your user uses the music player app on a tablet in landscape mode you have more space for displaying stuff. Then the activity shows the list fragment (which also gets displayed in portrait mode) and it shows a third fragment which shows detailed information about the current playing song (e.g. the album image) and a progress bar.
By using fragments you only need to write the code for the list once.
Sweet and Simple thing, What i recommend is always use Fragments,
But for Fragment you will require Activity.
Take it in this way , Activity is a Canvas on which you can put any number of Fragments.
Whatever your UI is always use Fragment present on a activity if you want to show one screen even then also, So that you will always have Flexibilty to use all those cool things which fragments provides,maybe in future or in current.
If you use activity it has limits,FOR EXAMPLE, LIKE in INSTAGRAM AT BOTTOM, It has FIVE OPTIONS, Suppose THOSE OPTIONS ARE ON A ACTIVITY AND BY CLICKING ON THEM YOU CAN SWITCH TO DIFFERENT FRAGMENTS.
For more info:
Here is the most accepted answer for this topic.
I am following the Google tutorial for building your first android application. I got to the point where I needed to implement the actionbar actions with the functions openSearch() and openSettings().
I implemented all of this in the MainActivity.java file.
My question is this:
In the example app you can type a message and then send it and it displays it in a second activity. In the second activity, the top action bar changes and does not display my Search icon or perform the action when the settings button is clicked. In order to have these icons displayed in the action bar for this activity as well, do I need to add those methods and update onOptionsItemSelected method in DisplayMessageActivity.java as well as in MainActivity.java? Is this the only way to carry the action bar icons/actions over? To retype the same methods in each activity that you want them in? Or is there a better way to do it?
My other somewhat related curiosity is this. The method openSettings() is called when I click the 3 vertical dots and then settings. These 3 vertical dots show up on every activity, and settings is always in the list. However clicking settings obviously doesn't perform the call to openSettings() when in the DisplayMessageActivity and not MainActivity. How is it that settings and the vertical dots are carried over?
Second to last, how can I add other selections to the drop down list from the options/vertical dots in the action bar? Settings is always there although it responds differently in each activity which was my first question. But I would like to add certain things to the options menu that are on all activities, and some things that are unique to some activities. I assume there must be a better way than repeating switch statements and methods in every Activity.java file.
And finally, what is the best practice to implement an action bar over multiple activities?
Obviously different activities will often have different icons/actions in the action bar, however some things like the 3 vertical dots(options) and settings within that would obviously be acceptable to have in every Activity, while it would be nice to add other things to the options list I don't see why settings should ever change across activities. Yet as I stated before the method is not called in DisplayMessageActivity unless I repeat the code in DisplayMessageActivity.java that I had added to MainActivity.java. I'm confused as to where I can add these so that they are displayed on all activities without repeating code. And I'm confused as to how the actionbar's options/vertical dots are carried over to all activities while others require the repeating of code in each activities' java file that I want them to show up in.
I know this was a bit of a long winded quesiton, I will clarify if necessary. I'm just a bit confused. I was able to make it through the tutorial fine as I have a decent understanding of java. However google's guide isn't written that well and the Android environment is very confusing to a beginner.
I do understand how things work to a degree, I just want to ensure that I'm actually doing it in a way that when my app grows in complexity it won't be a mess of unnecessarily repeated statements and methods.
Thanks in advance for any assistance and tips.
In order to have these icons displayed in the action bar for this activity as well, do I need to add those methods and update onOptionsItemSelected method in DisplayMessageActivity.java as well as in MainActivity.java? Is this the only way to carry the action bar icons/actions over? To retype the same methods in each activity that you want them in? Or is there a better way to do it?
That is certainly one solution, but as you obviously know, it's not a very good one. There are at least two alternative solutions:
Create a MenuActivity class which implements all the logic for common menu items and then extend this class from all of your activities, rather than extending the standard Activity class.
Use fragments to implement your UI. Fragments are similar to activities in that they create UI elements from an XML layout. One difference is that they live inside a "host activity". In this particular case, the host activity will provide the common menu functionality and each fragment can customize it further depending on your needs.
How is it that settings and the vertical dots are carried over?
Most likely your DisplayMessageActivity overrides onCreateOptionsMenu() and inflates a menu XML layout which was created by Android Studio (or Eclipse?) when you created the activity class.
My app has an album style feature that users can pick/take photos from device and load it in every page in this album.
Now the number of this album pages is up to user and should be unlimited. On the Other hand the codes that is being used in activities as you could imagine are exactly same. I have wrote code once and I just want to reuse this activity for each page of album. how should I achieve this?
Since there are thousands of apps that are provide this kind of functions I know there is a good way but i'm unable to find that. Just a trick or a link to a tutorial or even a small explanation is good enough.
Thanks in Advance.
You can create a next() method, and change every layout view in the page with this function, so that you are in same activity but only views are being changed.
One solution is to add the data to be displayed to the "extras" of the Intent which you use to start the activity.
Alternatively, you might want to look at using a Fragment instead of an Activity. You might also want to look at using ViewPager to be able to swipe through the fragments which display the album data.