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This should also include "weatherDao"

So it would look like "Update SunshineRepository, WeatherDao, ViewModel and Adapter

Hello,
Like mentioned on the title i can not find this class com.example.android.sunshine.R

Needed to add this to the bottom of the module app build.gradle
Android Studio 3.1.2

configurations.all {
    resolutionStrategy.eachDependency { DependencyResolveDetails details ->
        def requested = details.requested
        if (requested.group == 'com.android.support') {
            if (!requested.name.startsWith("multidex")) {
                details.useVersion '26.1.0'
            }
        }
    }
}

https://codelabs.developers.google.com/codelabs/build-app-with-arch-components/index.html

Doesn't compile.

This pertains to the lesson text and not the code (code compiles and runs just fine).

Near the end of the lesson for Step 11, after observing the logs.

"2. When SunshineData.intializeData() is called"

This may be incorrect.  Shouldn't "SunshineData"be "SunshineRepository" like this?

"2. When SunshineRepository.intializeData() is called"

I can not find the classes: ActivityDetailBinding,DataBindingUtil

Hi!

In the section titled "Your Turn: Complete the logic for fetching data", step 3, It says the following

In SunshineSyncIntertService, in onHandleIntent(), call the WeatherNetworkDataSource's fetchWeather() method.

When it should say

In SunshineSyncIntentService, in onHandleIntent(), call the WeatherNetworkDataSource's fetchWeather() method.

Make the ListViewWeatherEntry class
=>
Make the ListWeatherEntry class

Also:

I'm not sure, but should "Select only the rows you need" be "Select only the columns you need"?

Hopefully this code lab should have an another branch for kotlin

LifecycleActivity has been deprecated since android.arch.lifecycle libs are stable version.

Fourth step in introduction to ViewModels can be removed

On step 9, you are including the following dependencies for lifecycle:

compile "android.arch.lifecycle:runtime:1.0.0-alpha9"
compile "android.arch.lifecycle:extensions:1.0.0-alpha9"
annotationProcessor "android.arch.lifecycle:compiler:1.0.0-alpha9"

but with this libreries the postValue() make my application crash, instead of this I use:

implementation "android.arch.lifecycle:runtime:1.0.0"
implementation "android.arch.lifecycle:extensions:1.0.0"
annotationProcessor "android.arch.lifecycle:compiler:1.0.0"

and i change again DetailActivity extends from AppCompatActivity instead of LifecycleActivity, because on this version is deprecated.

If his problem is also fixed, could you please, update this tutorial?

Same issue as #38

getInstance Method needs another null check inside the synchronized block

In code lab: Step 11, "Your Turn: Complete the logic for fetching data", part 3

There is a race condition in the getInstance method in SunshineRepository.java.

Imagine there are 2 threads - A and B - both calling getInstance() and that sInstance is null to start with

Thread A
Checks if sInstance is null. Returns True

Thread B
Checks if sInstance is null. Returns True

Thread A
Obtains the lock and creates a new instance for sInstance. Releases lock

Thread B
Remember Thread B already checked if sInstance was null earlier.
Obtains the lock and creates a new instance for sInstance. Releases lock

There should be a second null check inside the synchronized block.

• Room
• LiveData
• ViewModel
• Retrofit

Sunhine-Architecture-Components

I've found no example code available from google (or anyone) of unit tests that depend on mocking the Room database and tightly coupled dao objects:
SunshineDatabase.getInstance(context).weatherDao();
Note: I'm explicitly not talking about instrumented tests.

I used PowerMock(ito) to mock the canonical RoomDatabase.getInstance() static method at the heart of it all. Is this the best way? Or is it skipped because Dagger2 is the preferred way, and that is deemed to complex for these example apps?

Either way, please add best practice examples of unit testing Room with mocks, whether it be with dependency injection or mocking the static getInstance() method.

Thanks.

• In step 13, there is first sub point which is "doa" instead of "dao".
• In step 16, there are all bullet points, in which "Steps:" in also bullet point. It should be without bullet because it denotes that below in steps.

Thanks

There is a typo in https://codelabs.developers.google.com/codelabs/build-app-with-arch-components/index.html?index=..%2F..%2Findex#11:

The WeatherDao returns the data you want and you could have the DetailActivityViewModel communicate directly with the WeahterDao. But that defeats the whole point of the repository class; the repository should be the single source of truth for all data operations. Therefore the DetailActivityViewModel will get this data from the SunshineRepository. The SunshineRepository will, in turn, ask the WeatherDao for the LiveData:

Since the January 22, 2018 release of Architecture components, LifecycleActivity is deprecated.

The build.gradle file can be updated to:

implementation "android.arch.lifecycle:runtime:1.1.1"
implementation "android.arch.lifecycle:extensions:1.1.1"
annotationProcessor "android.arch.lifecycle:compiler:1.1.1"

and at point 4.) Open ui.detail.DetailActivity. Have DetailActivity extend LifecycleActivity instead of AppCompatActivity. we should just keep it AppCompatActivity

The variable type mentioned in the diagram is LiveData<List<List>> while it should have been LiveData<List> in MainActivityViewModel Box .

"WeatherNetworkDatasource is created via InjectorUtilis..."

Should be InjectorUtils

In step 9 -> under LiveData -> in the 6th paragraph -> Second sentence: The period at the end of this sentence is delimited as ., instead of a regular period.

Check out my fork here. I have changed nothing besides updating all the Gradle and dependencies versions.

Your Turn: The DetailActivityViewModel

4. Open ui.detail.DetailActivity. Have DetailActivity extend LifecycleActivity instead of AppCompatActivity.

is there any activity name LifecycleActivity?

in step 14 when you're about to go through the steps, the first point says:

Make new doa command for a list of forecasts after a date

I think this is supposed to be dao? maybe you could just call it Dao :)

Then this point:

Also make a factory, you can model this off of the detail view model factor almost entirely

factor == factory?

also suggest view model to be ViewModel as this is already in the context of android :)

Uncomment injector utils

== Uncomment InjectorUtils ?

hope this helps with the doc.

My issue addresses the part in the class named "AppExecutors", at line 47 there is a method named "getInstance", at the section :
public static AppExecutors getInstance() { if (sInstance == null) { synchronized (LOCK) { sInstance = new AppExecutors(Executors.newSingleThreadExecutor(), Executors.newFixedThreadPool(3), new MainThreadExecutor()); } } return sInstance; }

This synchronized block does not actually avoid the race condition; consider the following scenario :
Thread 1 & Thread 2, they both call "getInstance" method at the same exact time for the very first time, then both will evaluate "if (sInstance == null)" to be True, thus the first one to acquire the lock will instantiate "sInstance" and then the other thread will acquire the lock afterwards thus, re-instantiating the "sInstance" variable once again, which is what we were trying to avoid in the first place.

So, to only instantiate "sInstance" only exactly once no matter what, you could either swap the condition line with the synchronized line like so :
synchronized (LOCK) { if (sInstance == null) { sInstance = new AppExecutors(Executors.newSingleThreadExecutor(), Executors.newFixedThreadPool(3), new MainThreadExecutor()); } }

Or to actually remove the synchronized block altogether and just make the whole function Synchronized like so :
synchronized public static AppExecutors getInstance() { if (sInstance == null) { sInstance = new AppExecutors(Executors.newSingleThreadExecutor(), Executors.newFixedThreadPool(3), new MainThreadExecutor()); } return sInstance; }

This will ensure 100% that "sInstance" will only be instantiated exactly once.

Thanks for your support.

In lesson 9: Intro to ViewModels and LiveData, step 4 says "Open ui.detail.DetailActivity. Have DetailActivity extend LifecycleActivity instead of AppCompatActivity." LifecycleActivity is now a component of AppCompatActivity. Extending LifecycleActivity will produce compile errors.

All the libraries in the project are needed to be upgraded along with the documentation https://codelabs.developers.google.com/codelabs/build-app-with-arch-components/#0

Kindly update the documentation and the project libraries. It's taking longer than the given time-frame to complete the tasks. Adding navigation component to the project would be good.

Sorry if this may seem too basic, but I can't wrap my head around the concept of ViewModelProvider factories. Why do we need factories? And is this the only way to create viewmodels in an activity? Thanks

This is what I get when I Try to Build the project

Manifest merger failed : Attribute meta-data#android.support.VERSION@value value=(26.0.1) from [com.android.support:preference-v7:26.0.1] AndroidManifest.xml:25:13-35
	is also present at [com.android.support:support-core-utils:26.1.0] AndroidManifest.xml:28:13-35 value=(26.1.0).
	Suggestion: add 'tools:replace="android:value"' to <meta-data> element at AndroidManifest.xml:23:9-25:38 to override.

If you're a developer, you can get it here:
https://github.com/edwardotis/android-build-an-app-architecture-components

If you're a Google employee, please approve my PR here:
#36

In Step 5 towards the end there's the following snippet:

allprojects {
    repositories {
        jcenter()
        maven { url 'https://maven.google.com' }
    }
}

but this repository build.gradle uses the short version google(). That might be confusing.

Under "Create an Entity", the third step ("The date field should be unique") has a hyperlink on "Indices." However, this merely links to the landing page for Room.
As the link above does not talk in specific about indices, would this be the intended link for indices in Room? If you could confirm on the link, I will be happy to raise a PR with the fix.
Thanks! :)