dependencies {
    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.4.0'

ViewModel class and LiveData

class PracticeProgressViewModel : ViewModel() {
    
    private val _text = MutableLiveData<String>().apply {
        value = ""
    }

    val text: MutableLiveData<String> = _text

    fun setText(value: String){
        _text.value = value
    }
}

Fragment

class PracticeProgressFragment : Fragment() {

    private val homeViewModel: PracticeProgressViewModel by activityViewModels()

Observer Pattern

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {

        homeViewModel.text.observe(viewLifecycleOwner, {
            textView.text = it
        })

Update the ViewModel

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val button = binding.button
        button.setOnClickListener(View.OnClickListener {
        
            val totalAmoint = practiceDao.getTotalAmount()
            homeViewModel.setText(totalAmoint.toString())
        })
    }

The post How to use ViewModel in Android appeared first on Creatronix.

Architecture

Source Code

is hosted here: https://android.googlesource.com/platform/manifest

Google uses repo (basically a git wrapper written in python) to clone the source code.

You can find the instructions here:  https://source.android.com/setup/build/downloading

Further Reading

What is Ninja?

What is kapt?

Anatomy of a Gradle file

The post What is the AOSP? appeared first on Creatronix.

Dependency

implementation 'com.google.android.material:material:1.4.0'

Layout

A snackbar must be tied to a coordinator layout. If you use fragments the standard layout is FrameLayout which can be directly swapped with:

<androidx.coordinatorlayout.widget.CoordinatorLayout

Snackbar

val snackbar = Snackbar.make( 
    binding.root, 
    "No internet connection! Please enable WiFi or Mobile Data", 
    Snackbar.LENGTH_INDEFINITE ) 
snackbar.show()

Further Reading

Passing data between fragments using SafeArgs

Dependency Injection with Koin and Kotlin in Android

How to use ViewModel in Android

The post How to use Snackbars appeared first on Creatronix.

Sometimes you want to redirect the user from your app to the website for e.g. imprint and data protection info.

So it can be helpful to open up a website directly from your app.

Implementation

In Switch between activities you learned that the standard way of switching between activities is an intent.

The same goes for open up the browser on your phone. The intent is called the “ACTION_VIEW”

import android.content.Intent
import android.net.Uri
val browserIntent = Intent(Intent.ACTION_VIEW)
browserIntent.data = Uri.parse("https://prestissimo-guitar.com/")
startActivity(browserIntent)

Further Reading

Passing data between AndroidActivities

Passing data between fragments using SafeArgs

Pass custom objects via SafeArgs

The post How to open a URL in a browser from your Android app appeared first on Creatronix.

Timber is built upon Android’s Log class. If you are not yet familiar with logging in Android have a look at Logging in Android

Dependency

Timber has just on dependency. Nice!

dependencies {
  implementation 'com.jakewharton.timber:timber:5.0.1'
}

Initialization in Application

To use Timber in your app you need an application class where you call the static method Timber.plant

import android.app.Application
import timber.log.Timber

class LevelUpApplication : Application()  {
    override fun onCreate() {
        super.onCreate()
        if (BuildConfig.DEBUG) {
            Timber.plant(DebugTree())
        }
    } 
}

Make sure that your custom application class is referenced in your manifest:

<application
    android:name=".LevelUpApplication"
    ...
>

Import & Logging

After you have added Timber Android Studio highlights the old log statements:

Timber is imported via

import timber.log.Timber

And the new log statement looks like this:

Timber.d("onCreate")

The new log statement has no TAG element so you can remove the companion object from your class.

Timber on github

The post Logging in Android with Timber appeared first on Creatronix.

• Create a new folder e.g. app/src/main/res/values-de
• Add strings.xml into this folder
• Translate the content

The cool thing about translation in android is that you can do it incrementally: when there is no translation for a string resource in a locale Android will automagically use the value from /res/values/strings.xml

The post Localization of Android Apps appeared first on Creatronix.

You have to provide a SHA-1 key which can be generated as following:

Command line

$ chmod u+x gradlew
$ ./gradlew signingReport

The post Generating SHA-1 for Google API appeared first on Creatronix.

private void openVideoActivity(String video) {
    Intent newActivity = new Intent(this, PlayerActivity.class);
    newActivity.putExtra("videoId", video);
    startActivity(newActivity);
}

Retrieving data

final String videoID = getIntent().getExtras().getString("videoID");

In Kotlin it looks like this:

val intent = Intent(this, NewActivity::class.java).apply {
    putExtra("EXTRA_MESSAGE", "Test 123")
}
startActivity(intent)

Retrieving

val message = intent.getStringExtra("EXTRA_MESSAGE")

Further Reading

Passing data between fragments using SafeArgs

Pass custom objects via SafeArgs

The post Passing data between AndroidActivities appeared first on Creatronix.

A permission is something an app is allowed to do 🙂

E.g. using the camera, reading location or accessing your contacts.

<uses-permission android:name="android.permission.CAMERA" /> 
<uses-feature android:name="android.hardware.camera" android:required="true" />

Internet Access

If your app uses e.g. web-APIs you need internet access. This can be achieved by adding android.permission.INTERNET to your manifest. In this case you need the uses-permission tag.

<manifest package="de.creatronix.sample_app" xmlns:android="http://schemas.android.com/apk/res/android"> 
<uses-permission android:name="android.permission.INTERNET"/> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

INTERNET

Allows applications to open network sockets.

ACCESS_NETWORK_STATE

Allows applications to access information about networks.

Non-TLS APIs

When You have resources which do not use TLS (https but just http) you have to add

<application 
... 
android:usesCleartextTraffic="true"> 
</application>

Permissions in Services

Checking Permission

import android.content.pm.PackageManager;
int uid = getCallingUid(); 
int pid = getCallingPid(); 
Log.d(LOGTAG, "Message from PID " + pid + " UID " + uid);
int perm = mContext.checkPermission("de.creatronix.my_service.MY_PERM", pid, uid); 
if (perm == PackageManager.PERMISSION_GRANTED) 
    Log.d(LOGTAG, "Granted"); 
else 
    Log.d(LOGTAG, "Denied");

Enforcing Permissions

mContext.enforceCallingPermission("de.creatronix.my_service.MY_PERM", "echoString permission not granted"); 

More about permissions:
https://developer.android.com/reference/android/Manifest.permission.html

The post Features and Permissions in Android appeared first on Creatronix.

Recommended by my colleague Jens Dittmar this little helper improved my workday a lot. Let’s see it in action first:

Documents

Let’s say You have a book cover like this:

Now we take a photo of it with MS Office Lens. What the app does is detecting the edges of a document and highlights them like that:

If you now take the photo it automagically crops the image, rectifies the edges and improves the contrast. This is what you get without further adjustments:

I’m not an expert in image processing but it seems like the app does some gamma correction, too.

I think the result is amazing when you consider that you don’t have to fumble with any settings so far!

Whiteboard

OK, another use case. You did some brainstorming on a whiteboard and want to send a picture to your colleagues. As You can see a conventional photo is a bit poor.

This is the part where Office Lens comes in handy:

The only drawback: it does not improve your handwriting 😉

Business Cards

I don’t get business cards very often but when I do I want to have a nice little photo of ’em. (No meme intended 🙂 ) Does it work? Does it even work with black business cards?

Well, yes it does work. Again, the edges are detected and rectified, contrast and gamma improved. (The font does look like this intentionally 🙂 )

Bottom Line

I really like this app because it does one thing and this one thing great! With this app there is definitely no need anymore to keep a scanner around.

You can get the app for free for iOS, and Android

The post Review Microsoft Lens appeared first on Creatronix.