How to receive data instantly with Architecture Compoenents?
I'm trying to implement the recommended architecture by Google and in a tutorial they show this diagram:
So I have a MainActivity and when the app starts it should go and fetch some data from the internet. I do those network operations in the Repository. Now my problem is that I don't know how to communicate properly between activities and Repository. For example MainActivity starts and immediately display a circular progress bar while Repository fetches the data. How can I stop the animation in MainActivity as soon as the data is inserted to the database? I guess I could call observe() on the LiveData and wait for onChanged(). Is there a better approach? What if there is no new data? Then onChanged() wouldn't be called...
Maybe I could send intent from Repository to MainActivity when there is no data so MainActivity knows it should stop the animation and if it doesn't receive the intent it just waits for onChanged()?
I guess I just don't feel confortable with the onChanged() method because I will never be sure of the operation it corresponds to. Maybe before the data from the network arrived there was some other data inserted which trigged onChanged() which would then stop the loading animation before it was supposed to.
android architecture android-livedata edited Nov 21 at 8:25
Knossos
11.3k74171
asked Nov 20 at 18:00
xpland
32
add a comment |
I'm trying to implement the recommended architecture by Google and in a tutorial they show this diagram:
So I have a MainActivity and when the app starts it should go and fetch some data from the internet. I do those network operations in the Repository. Now my problem is that I don't know how to communicate properly between activities and Repository. For example MainActivity starts and immediately display a circular progress bar while Repository fetches the data. How can I stop the animation in MainActivity as soon as the data is inserted to the database? I guess I could call observe() on the LiveData and wait for onChanged(). Is there a better approach? What if there is no new data? Then onChanged() wouldn't be called...
Maybe I could send intent from Repository to MainActivity when there is no data so MainActivity knows it should stop the animation and if it doesn't receive the intent it just waits for onChanged()?
I guess I just don't feel confortable with the onChanged() method because I will never be sure of the operation it corresponds to. Maybe before the data from the network arrived there was some other data inserted which trigged onChanged() which would then stop the loading animation before it was supposed to.
android architecture android-livedata edited Nov 21 at 8:25
Knossos
11.3k74171
asked Nov 20 at 18:00
xpland
32
Firstly, you don't mentionViewModel- are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?
– Knossos
Nov 21 at 8:31
@Knossos Yes I'm usingViewModeland alsoRoomto store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?
– xpland
Nov 21 at 10:04
add a comment |
I'm trying to implement the recommended architecture by Google and in a tutorial they show this diagram:
So I have a MainActivity and when the app starts it should go and fetch some data from the internet. I do those network operations in the Repository. Now my problem is that I don't know how to communicate properly between activities and Repository. For example MainActivity starts and immediately display a circular progress bar while Repository fetches the data. How can I stop the animation in MainActivity as soon as the data is inserted to the database? I guess I could call observe() on the LiveData and wait for onChanged(). Is there a better approach? What if there is no new data? Then onChanged() wouldn't be called...
Maybe I could send intent from Repository to MainActivity when there is no data so MainActivity knows it should stop the animation and if it doesn't receive the intent it just waits for onChanged()?
I guess I just don't feel confortable with the onChanged() method because I will never be sure of the operation it corresponds to. Maybe before the data from the network arrived there was some other data inserted which trigged onChanged() which would then stop the loading animation before it was supposed to.
android architecture android-livedata edited Nov 21 at 8:25
Knossos
11.3k74171
asked Nov 20 at 18:00
xpland
32
I'm trying to implement the recommended architecture by Google and in a tutorial they show this diagram:
So I have a MainActivity and when the app starts it should go and fetch some data from the internet. I do those network operations in the Repository. Now my problem is that I don't know how to communicate properly between activities and Repository. For example MainActivity starts and immediately display a circular progress bar while Repository fetches the data. How can I stop the animation in MainActivity as soon as the data is inserted to the database? I guess I could call observe() on the LiveData and wait for onChanged(). Is there a better approach? What if there is no new data? Then onChanged() wouldn't be called...
Maybe I could send intent from Repository to MainActivity when there is no data so MainActivity knows it should stop the animation and if it doesn't receive the intent it just waits for onChanged()?
I guess I just don't feel confortable with the onChanged() method because I will never be sure of the operation it corresponds to. Maybe before the data from the network arrived there was some other data inserted which trigged onChanged() which would then stop the loading animation before it was supposed to.
android architecture android-livedata android architecture android-livedata edited Nov 21 at 8:25
Knossos
11.3k74171
asked Nov 20 at 18:00
xpland
32
edited Nov 21 at 8:25
Knossos
11.3k74171
asked Nov 20 at 18:00
xpland
32
edited Nov 21 at 8:25
Knossos
11.3k74171
edited Nov 21 at 8:25
Knossos
11.3k74171
edited Nov 21 at 8:25
Knossos
11.3k74171
11.3k74171
asked Nov 20 at 18:00
xpland
32
asked Nov 20 at 18:00
xpland
32
asked Nov 20 at 18:00
xpland
32
32
Firstly, you don't mentionViewModel- are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?
– Knossos
Nov 21 at 8:31
@Knossos Yes I'm usingViewModeland alsoRoomto store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?
– xpland
Nov 21 at 10:04
add a comment |
Firstly, you don't mentionViewModel- are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?
– Knossos
Nov 21 at 8:31
@Knossos Yes I'm usingViewModeland alsoRoomto store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?
– xpland
Nov 21 at 10:04
Firstly, you don't mention
ViewModel - are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?– Knossos
Nov 21 at 8:31
Firstly, you don't mention
ViewModel - are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?– Knossos
Nov 21 at 8:31
@Knossos Yes I'm using
ViewModel and also Room to store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?– xpland
Nov 21 at 10:04
@Knossos Yes I'm using
ViewModel and also Room to store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?– xpland
Nov 21 at 10:04
add a comment |
1 Answer
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oldest
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Regarding your issue in the comments, which I believe to answer your main question also.
You need to observe from your UI (Activity / Fragment) to a progress LiveData in your ViewModel. That could be working with a Boolean (LiveData<Boolean>). To represent the progress view being visible or not.
That in turn needs to take an identical LiveData from the Repository (declared in the Repository as a MutableLiveData). You then post updates to the progress MutableLiveData in the Repository.
Now, whenever the MutableLiveData receives a change, that exists in your ViewModel as it shares the variable reference, and it will pass to the observer in your UI.
-
Alternatively, you could return a LiveData<Boolean> from the method in your Repository that pulls data. That would then be observable in your UI.
Instead of Boolean, you could also use a more complicated structure containing more information. A message, error code, etc.
answered Nov 21 at 10:20
Knossos
11.3k74171
add a comment |
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Regarding your issue in the comments, which I believe to answer your main question also.
You need to observe from your UI (Activity / Fragment) to a progress LiveData in your ViewModel. That could be working with a Boolean (LiveData<Boolean>). To represent the progress view being visible or not.
That in turn needs to take an identical LiveData from the Repository (declared in the Repository as a MutableLiveData). You then post updates to the progress MutableLiveData in the Repository.
Now, whenever the MutableLiveData receives a change, that exists in your ViewModel as it shares the variable reference, and it will pass to the observer in your UI.
-
Alternatively, you could return a LiveData<Boolean> from the method in your Repository that pulls data. That would then be observable in your UI.
Instead of Boolean, you could also use a more complicated structure containing more information. A message, error code, etc.
answered Nov 21 at 10:20
Knossos
11.3k74171
add a comment |
Regarding your issue in the comments, which I believe to answer your main question also.
You need to observe from your UI (Activity / Fragment) to a progress LiveData in your ViewModel. That could be working with a Boolean (LiveData<Boolean>). To represent the progress view being visible or not.
That in turn needs to take an identical LiveData from the Repository (declared in the Repository as a MutableLiveData). You then post updates to the progress MutableLiveData in the Repository.
Now, whenever the MutableLiveData receives a change, that exists in your ViewModel as it shares the variable reference, and it will pass to the observer in your UI.
-
Alternatively, you could return a LiveData<Boolean> from the method in your Repository that pulls data. That would then be observable in your UI.
Instead of Boolean, you could also use a more complicated structure containing more information. A message, error code, etc.
answered Nov 21 at 10:20
Knossos
11.3k74171
add a comment |
Regarding your issue in the comments, which I believe to answer your main question also.
You need to observe from your UI (Activity / Fragment) to a progress LiveData in your ViewModel. That could be working with a Boolean (LiveData<Boolean>). To represent the progress view being visible or not.
That in turn needs to take an identical LiveData from the Repository (declared in the Repository as a MutableLiveData). You then post updates to the progress MutableLiveData in the Repository.
Now, whenever the MutableLiveData receives a change, that exists in your ViewModel as it shares the variable reference, and it will pass to the observer in your UI.
-
Alternatively, you could return a LiveData<Boolean> from the method in your Repository that pulls data. That would then be observable in your UI.
Instead of Boolean, you could also use a more complicated structure containing more information. A message, error code, etc.
answered Nov 21 at 10:20
Knossos
11.3k74171
Regarding your issue in the comments, which I believe to answer your main question also.
You need to observe from your UI (Activity / Fragment) to a progress LiveData in your ViewModel. That could be working with a Boolean (LiveData<Boolean>). To represent the progress view being visible or not.
That in turn needs to take an identical LiveData from the Repository (declared in the Repository as a MutableLiveData). You then post updates to the progress MutableLiveData in the Repository.
Now, whenever the MutableLiveData receives a change, that exists in your ViewModel as it shares the variable reference, and it will pass to the observer in your UI.
-
Alternatively, you could return a LiveData<Boolean> from the method in your Repository that pulls data. That would then be observable in your UI.
Instead of Boolean, you could also use a more complicated structure containing more information. A message, error code, etc.
answered Nov 21 at 10:20
Knossos
11.3k74171
edited Nov 21 at 11:20
answered Nov 21 at 10:20
Knossos
11.3k74171
answered Nov 21 at 10:20
Knossos
11.3k74171
answered Nov 21 at 10:20
Knossos
11.3k74171
11.3k74171
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Firstly, you don't mention
ViewModel- are you using that? That is an important middleman. Secondly, are you using Room to store data, or only from the internet?– Knossos
Nov 21 at 8:31
@Knossos Yes I'm using
ViewModeland alsoRoomto store the data in the database. The loading progress bar is a good example of my difficulties. I only want to stop that animation in MainActivity when the freshest data arrives. How do I implement that using this architecture?– xpland
Nov 21 at 10:04