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Android Shrink Resources, Resource Not Found

Sun, 05 Jul 2020 00:00:00 +0000

Recently I came across an issue when using Google Cast SDK with R8(Proguard) and Shrinkresources. My debug build seems to work well, but release build compiles and installs… But crashes as soon as it opens. :thinking:

Let’s look into the crash logs.

 Caused by: android.content.res.Resources$NotFoundException: Drawable com.sample.application:drawable/mr_button_light with resource ID #0x7f08018a
     Caused by: android.content.res.Resources$NotFoundException: File res/drawable/mr_button_light.xml from drawable resource ID #0x7f08018a
        at android.content.res.ResourcesImpl.loadDrawableForCookie(ResourcesImpl.java:876)
        at android.content.res.ResourcesImpl.loadDrawable(ResourcesImpl.java:659)
        at android.content.res.Resources.getDrawableForDensity(Resources.java:906)
        at android.content.res.Resources.getDrawable(Resources.java:845)
        at android.content.res.Resources.getDrawable(Resources.java:820)
        at androidx.mediarouter.app.MediaRouteButton$b.doInBackground(:1)
        ...
     Caused by: android.view.InflateException: Class not found x
        at android.graphics.drawable.DrawableInflater.inflateFromClass(DrawableInflater.java:224)
        at android.graphics.drawable.DrawableInflater.inflateFromXmlForDensity(DrawableInflater.java:141)
        at android.graphics.drawable.Drawable.createFromXmlInnerForDensity(Drawable.java:1402)
        at android.graphics.drawable.Drawable.createFromXmlForDensity(Drawable.java:1361)
        at android.content.res.ResourcesImpl.loadXmlDrawable(ResourcesImpl.java:939)
        at android.content.res.ResourcesImpl.loadDrawableForCookie(ResourcesImpl.java:862)
        at android.content.res.ResourcesImpl.loadDrawable(ResourcesImpl.java:659) 
        at android.content.res.Resources.getDrawableForDensity(Resources.java:906) 
        at android.content.res.Resources.getDrawable(Resources.java:845) 
        at android.content.res.Resources.getDrawable(Resources.java:820) 
        at androidx.mediarouter.app.MediaRouteButton$b.doInBackground(:1) 
        ...
     Caused by: java.lang.ClassNotFoundException: Didn't find class "x" on path: DexPathList[[zip file "/data/app/com.sample.

The problem - R8 assumes these mr_*resources (media router) are unused and are skipped to be included with the build. Hence, while accessing them via reflection in the code by the Cast SDK it fails.

How can we fix it?

As stated in the Android developers documentation

res/raw/keep.xml

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:tools="http://schemas.android.com/tools"
    tools:keep="@drawable/mr_*" />

The above xml tells the gradle plugin not to shrink resources of this kind.

How can we verify this?

run ./gradlew clean bundleStageRelease –info » output.txt

Search around the file, if skip unsed is been shown for mr_ files.
Now go back add the keep.xml file and repeat the same.

I hope it helps!

References

Basics of Easing Animations in android

Thu, 12 Nov 2015 14:34:25 +0000

An easing function describes the value of a property given a percentage of completeness. Thanks to Robert Penner for defining equations which drove animations with ease.

How do we do this android ? First lets see how we do animations with ValueAnimator.

Setting up Activity

app/package.name/MainActivity.java

Button click;
View view;
@Override
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
	view = (View)findViewById(R.id.view);
	click = (Button)findViewById(R.id.button);
	click.setOnClickListener(clickListener);
}
View.OnClickListener clickListener = new View.OnClickListener() {
	@Override
	public void onClick(View v) {
    	ease();      
    }
};

Our XML layout

<View
    android:id="@+id/view"
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:background="@android:color/holo_blue_bright"/>
<Button
    android:id="@+id/button"
    android:text="Click"
    android:layout_width="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_height="60dp"/>

Setup simple Animation

ValueAnimator class provides a simple timing engine for running animations which calculate animated values and set them on target objects . AnimatorSet class plays a set of Animator objects in the specified order. Animations can be set up to play together, in sequence, or after a specified delay.

We will be using these two classes to make our first animation.

app/package.name/MainActivity.java

private void ease() {
	AnimatorSet animatorSet = new AnimatorSet();
	ValueAnimator valueAnimatorX = ValueAnimator.ofFloat(fromX,toX, fromX);
	valueAnimatorX.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
		@Override
		public void onAnimationUpdate(ValueAnimator animation) {
			view.setTranslationX((float) animation.getAnimatedValue());
		}
	});
	animatorSet.playTogether(valueAnimatorX);
	animatorSet.setDuration(1500);
	animatorSet.start();
}

![Linear Animation](/assets/article_images/easing-animations-android/linear.gif)

This animations seems so boring. We need somthing cool.

Easing to make it awesome

ValueAnimator class accepts an evaluator, which defines on how the value is derived. So we make use of setEvaluator function and put our easing equations there to get the desired animation.

So make a class Easing implementing TypeEvaluator

app/package.name/Easing.java

public class Easing implements TypeEvaluator<Number> {
	@Override
    public Number evaluate(float fraction, Number startValue, Number endValue) {
    }
}

Now we have the evaluate methods which tell the ValueAnimator on how it should evaluate.

app/package.name/Easing.java

/**  
* Converts params to calculate easing values
* @param fraction
* @param startValue
* @param endValue
* @return
*/

@Override
public Number evaluate(float fraction, Number startValue, Number endValue) {
	float t = duration * fraction;
	float b = startValue.floatValue();
	float c = endValue.floatValue() - startValue.floatValue();
	float d = duration;
	float result = calculate(t,b,c,d);
	return result;

}

What’s the calculate method here? This method decides which easing equation we are going to use. There is a lot mentioned about equations here. You can edit this method based on any of the equations given and get your desired animation.

app/package.name/Easing.java

/**
* @param t - Current Time
* @param b - Start Value
* @param c - Change in value
* @param d - Duration
* @return value calculated for cubic ease-in-out
*/

public float calculate(float t, float b, float c, float d){
	t /= d/2;
	if (t < 1) {
		return c/2*t*t*t + b;
	}
	t -= 2;
	return c/2*(t*t*t + 2) + b;
}

Update MainAcvitity

Now we are good with the Easing class and ready to include it in our ValueAnimator.

app/package.name/MainActvity.java

private void ease() {
	Easing easing = new Easing(1500);
	...
	valueAnimatorX.setEvaluator(easing);
	valueAnimatorX.addUpdateListener(...)
	...
}

Uh! is that enough ?

Find the source code of the entire sample over here, Easing on Android.

AnimationEasingFunctions seems an awesome library to make easing animatons easier and lively.

CRUD on Android with Firebase API (Deprecated)

Wed, 09 Sep 2015 14:34:25 +0000

Firebase provides a powerful API to store, retrieve and sync data in realtime, which paves way for an accelerated development reducing the pain of setting up your backend. In this post we will get a quick glance of making a CRUD with [Firebase Android SDK][firebase-android]. Firebase also provides you with a [Quick Start][firebase-quick-start] guide to get on with its SDKs.

Once you have an account with [Firebase][firebase], create an app and note down the app's URL. This app URL will be used in our android application as the base URL to firebase.

Adding Dependencies

app/build.gradle

dependencies {
	compile 'com.firebase:firebase-client-android:2.3.1+'
}

Incase you end up with build errors,

android {
	...
	packagingOptions {
	exclude 'META-INF/LICENSE'
	exclude 'META-INF/LICENSE-FIREBASE.txt'
	exclude 'META-INF/NOTICE'
	}
}

Adding Permissions

app/src/main/AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />

Necessary Layout Components

Two EditText components, a ListView and a Button. These EditText components holds the name(key) and the message(value) to be saved. Button is used to trigger the save action using Firebase sdk and a ListView to display the data.

<EditText
	android:layout_width="fill_parent"
	android:layout_height="60dp"
	android:hint="Enter Name"
	android:id="@+id/name"
	android:layout_marginTop="10dp"
	android:layout_alignParentLeft="true"
	android:layout_alignParentStart="true"/>
<EditText
	android:layout_width="fill_parent"
	android:layout_height="60dp"
	android:hint="Enter Message"
	android:layout_marginTop="10dp"
	android:id="@+id/message"
	android:layout_below="@+id/name"/>
<Button
	android:layout_width="wrap_content"
	android:layout_height="wrap_content"
	android:text="Save"
	android:id="@+id/save"
	android:layout_below="@+id/message"
	android:layout_marginTop="10dp"
	android:layout_centerHorizontal="true"/>
<ListView
	android:layout_width="wrap_content"
	android:layout_height="fill_parent"
	android:id="@+id/listView"
	android:layout_below="@+id/save"
	android:layout_alignParentLeft="true"
	android:layout_alignParentStart="true"/>

Saving data on Firebase - Create

Declare necessary attributes.

Button save;
static Firebase myFirebaseRef;
EditText nameEditText;
EditText messageEditText;
ProgressBar progressBar;
static final String TAG = "Main Acvity";
ArrayAdapter<String> valuesAdapter;
ArrayList<String> displayArray;
ArrayList<String> keysArray;
ListView listView;

The OnCreate Function

@Override
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);

	/*View bindings*/
	save = (Button)findViewById(R.id.save);
	nameEditText = (EditText)findViewById(R.id.name);
	messageEditText= (EditText)findViewById(R.id.message);
	progressBar = (ProgressBar)findViewById(R.id.progressBar);
	listView = (ListView)findViewById(R.id.listView);

	/*Variable Initialization*/
	displayArray  = new ArrayList<>();
	keysArray = new ArrayList<>();
	valuesAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,android.R.id.text1,displayArray);
	listView.setAdapter(valuesAdapter);
	/*listView.setOnItemClickListener(itemClickListener);*/
	save.setOnClickListener(this);

	/*Firebase Initialization*/
	Firebase.setAndroidContext(this);
	myFirebaseRef = new Firebase("<appurl>");
	/*myFirebaseRef.addChildEventListener(childEventListener);*/
}

Adding click Listener to fire save action

@Override
public void onClick(View v) {
	switch (v.getId()){
		case R.id.save:
			String nameString = nameEditText.getText().toString();
			String messageString = messageEditText.getText().toString();
			save(nameString,messageString);
		break;
	}
}

private void save(String name,String message){
	myFirebaseRef.child(name).setValue(message, new Firebase.CompletionListener() {
		@Override
		public void onComplete(FirebaseError firebaseError, Firebase firebase) {
			nameEditText.setText("");
			messageEditText.setText("");
		}
	});
}

We have saved our data to firebase and on our onComplete method above we empty the edittext boxes. So where do we actually read our data and update the view?

Read data from Firebase - Read

Firebase provides a ChildEventListener which pops up when ever a change occurs to the specified child to which the event is bound. In our case we bind it to the myFirebaseRef, which is commented out initially on our onCreate method.

Events which we could listen to are onChildAdded, onChildChanged, onChildRemoved, onChildMoved, onCancelled.

ChildEventListener childEventListener = new ChildEventListener() {
	@Override
	public void onChildAdded(DataSnapshot dataSnapshot, String s) {
		Log.d(TAG, dataSnapshot.getKey() + ":" + dataSnapshot.getValue().toString());
		String keyAndValue = "Key: " +dataSnapshot.getKey().toString() + "\t Value: " +  	dataSnapshot.getValue().toString();
		displayArray.add(keyAndValue);
		keysArray.add(dataSnapshot.getKey().toString());
		updateListView();
	}
	@Override
	public void onChildChanged(DataSnapshot dataSnapshot, String s) {}
	@Override
	public void onChildRemoved(DataSnapshot dataSnapshot) {}
	@Override
	public void onChildMoved(DataSnapshot dataSnapshot, String s) { }
	@Override
	public void onCancelled(FirebaseError firebaseError) {}
};

private void updateListView(){
	valuesAdapter.notifyDataSetChanged();
	listView.invalidate();
	Log.d(TAG, "Length: " + displayArray.size());
}

Whenever a new child is added onChildAdded will get triggered and the view is updated corresponding to the received data.

Listen for changes in the child - Update

As we had seen, the above code provides a method to listen on changes made to the child data. We update our code on onChildChanged method to publish updates and show it to the user.

@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
	String changedKey = dataSnapshot.getKey();
	int changedIndex = keysArray.indexOf(changedKey);
	String keyAndValue = "Key: " +dataSnapshot.getKey().toString() + "\t Value: " + dataSnapshot.getValue().toString();
	displayArray.set(changedIndex,keyAndValue);
	updateListView();
}

Deleting a child - Delete

Now we uncomment itemClickListener for the listview. On click of an item in list view we delete the data based on the given name(Key).

AdapterView.OnItemClickListener itemClickListener = new AdapterView.OnItemClickListener() {
	@Override
	public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
		String clickedKey = keysArray.get(position);
		myFirebaseRef.child(clickedKey).removeValue();
	}
};

And again we override the onChildRemoved function and update the view

@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
	String deletedKey = dataSnapshot.getKey();
	int removedIndex = keysArray.indexOf(deletedKey);
	keysArray.remove(removedIndex);
	displayArray.remove(removedIndex);
	updateListView();
}

You can find the source code of the entire sample over here, [Firebase CRUD][firebase-crud] with few miscellaneous functions, [firebase]:https://www.firebase.com/ [firebase-android]:https://www.firebase.com/docs/android/ [firebase-quick-start]:https://www.firebase.com/docs/android/quickstart.html [firebase-crud]:https://github.com/shrikanthkr/FirebaseCRUD

Basics of Android GCM (Deprecated)

Tue, 08 Sep 2015 14:34:25 +0000

Google Cloud Messaging (GCM) is a service that enables developers to send data from servers to both Android applications or Chrome apps and extensions. Wikipedia.

GCM basics involves four steps

Registering the client (Android Device)
Provide the registration ID to server
Send notifications from Server to GCM with registration ID
Receive notifications on the client

Prerequisite

Project Number (845696541232)
Server API Key (XIzaSyBDRJ00YJbTE011CbWWjlcKYUGI3eLccdI)

Refer to Create Project on creating a new project and Generate API Key for generating a Server key(API Key)

Once we have all the required data we can start with our client registration process.

Creating a new Project

Ensure that we have the necessary dependencies added.

app/build.gradle

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'
    compile 'com.google.android.gms:play-services:6.5.87'
}

Adding Permissions

app/src/main/Androidmanifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android">
	...
	<uses-permission android:name="android.permission.INTERNET" />
	<uses-permission android:name="android.permission.WAKE_LOCK" />
	<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
	<permission android:name="com.example.gcm.permission.C2D_MESSAGE" android:protectionLevel="signature" />
	<uses-permission android:name="com.example.gcm.permission.C2D_MESSAGE" />
	...      
</manifest>

Registering the client (Android Device)

The client part has an interface with a registration button. On click of the button a call to GCM is made and Registration ID is obtained. While making the request it is necessary to note that we have the correct Project Number from the developers console.

res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:tools="http://schemas.android.com/tools"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:paddingLeft="@dimen/activity_horizontal_margin"
                android:paddingRight="@dimen/activity_horizontal_margin"
                android:paddingTop="@dimen/activity_vertical_margin"
                android:paddingBottom="@dimen/activity_vertical_margin"
                tools:context=".MainActivity">
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Register"
        android:id="@+id/register"
        android:layout_below="@+id/textView"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="117dp"/>

</RelativeLayout>

src/main/java/…/MainActivity.java

Declaring necessary variables and functions

Button register_button;
String PROJECT_NUMBER = "845696541232";
GoogleCloudMessaging gcmObj;
String regId;

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    register_button = (Button) findViewById(R.id.register);
    register_button.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        registerInBackground();
      }
    });

Writing the registration function

private void registerInBackground() {
	new AsyncTask<Void, Void, String>() {
		@Override
		protected String doInBackground(Void... params) {
			String msg = "";
			try {
				gcmObj = GoogleCloudMessaging.getInstance(getApplicationContext());
				regId = gcmObj.register(PROJECT_NUMBER);
				msg = "Registration ID :" + regId;
			} catch (IOException ex) { msg = ex.getMessage();}
			return msg;
		}
		@Override
		protected void onPostExecute(String msg) {
			Toast.makeText(getApplicationContext(),"Registered with GCM Server successfully.\n\n"+ msg, Toast.LENGTH_SHORT).show();
			Log.d("MainActivity", regId);
		}
	}.execute(null, null, null);
}

Provide the registration ID to server

Once the registration is successful, Registration ID is obtained. This Registration ID is used by the server to send notifications to device. In our sample the Registration ID printed in logs is copied and used in the server part.

Send notifications from Server to GCM with Registration ID (Server Part)

The sample server code here is written in Nodejs. Using node-gcm library we can easily send messages to GCM. The server part includes two files.

package.json
node-gcm-sample.js

package.json

{
  "dependencies": {
    "node-gcm": "git+https://github.com/ToothlessGear/node-gcm.git"
  }
}

node-gcm-sample.js

var gcm = require('node-gcm');
var message = new gcm.Message();
message.addData('key1', 'Awesome World!!'); /*Message to the client*/

var regIds = ['COPIED_ID_FROM_ANDROID_LOGS'];
var sender = new gcm.Sender('SERVER_API_KEY');

sender.send(message, { registrationIds: regIds } , function (err, result) {
  if(err) console.error(err);
  else    console.log(result);
});

Create both the files in a project folder, and execute npm install

Receive notifications on the client

Now we enter into the last part of preparing our client to receive notifications. We have to intimate the client to listen for notifications using a Receiver and a Service to handle the data from server.

src/main/java/…/GCMReceiver.java

Receiver code stating the necessary service (GCMIntentService) to be triggered.

public class GCMReceiver extends WakefulBroadcastReceiver{
	@Override
	public void onReceive(Context context, Intent intent) {
		ComponentName comp = new ComponentName(context.getPackageName(),GCMIntentService.class.getName());
		startWakefulService(context, (intent.setComponent(comp)));
		setResultCode(Activity.RESULT_OK);
	}
}

Update Androidmanifest

app/src/main/Androidmanifest.xml

<receiver
	android:name=".GCMReceiver"
	android:exported="true"
	android:permission="com.google.android.c2dm.permission.SEND" >
	<intent-filter>
		<action android:name="com.google.android.c2dm.intent.RECEIVE" />
		<category android:name="com.example.gcm" />
	</intent-filter>
</receiver>

src/main/java/…/GCMReceiver.java

Service code for handling the notifications part. Here MESSAGE_KEY is the expected key that is set from the server.

public class GCMIntentService extends IntentService {
	String MESSAGE_KEY = "key1";
	public GCMIntentService() {
		super("Message");
	}
	@Override
	protected void onHandleIntent(Intent intent) {
		Bundle extras = intent.getExtras();
		String message = intent.getStringExtra(MESSAGE_KEY);
		GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
		String messageType = gcm.getMessageType(intent);
		final int notificationID = (int) (Math.random() * 100000000);

		if (GoogleCloudMessaging.MESSAGE_TYPE_SEND_ERROR.equals(messageType)) {
			sendNotification("GCM notification: Send error" + extras.toString(), notificationID);
		}else if (GoogleCloudMessaging.MESSAGE_TYPE_DELETED.equals(messageType)) {
			sendNotification("Deleted messages on server" + extras.toString(), notificationID);
		}else if (GoogleCloudMessaging.MESSAGE_TYPE_MESSAGE.equals(messageType)) {
			sendNotification(message, notificationID);
		}
		GCMReceiver.completeWakefulIntent(intent);
	}

	private void sendNotification(String msg, int notificationID) {
		NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
		.setSmallIcon(R.drawable.common_ic_googleplayservices);
		.setContentTitle("Notification");
		.setContentText(msg);
		Intent resultIntent = new Intent(this, MainActivity.class);
		PendingIntent resultPendingIntent = PendingIntent.getActivity(this,0,resultIntent, PendingIntent.FLAG_UPDATE_CURRENT);
		NotificationManager mNotifyMgr = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
		mNotifyMgr.notify(notificationID, builder.build());
	}
}

Update Androidmanifest

app/src/main/Androidmanifest.xml

<service
	android:name=".GCMIntentService"
	android:exported="false" >
	<intent-filter>
		<action android:name="com.google.android.c2dm.intent.RECEIVE" />
	</intent-filter>
</service>

Now we are ready to check if our GCM component is working. Run the app in a device connected to internet, and open your server project folder from termial. Run node node-gcm-sample.js.Source code for Android Client and Node Server

Drawing borders in Android

Mon, 07 Sep 2015 14:34:25 +0000

To draw borders we have to understand the basics of layer-list drawable component. An exhaustive guide is provided by Android Developers Guide.

Code snippet to draw top and bottom borders:

res/drawable/border.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item><!--Item 1-->
	<shape android:shape="rectangle">
		<stroke android:color="@color/green"   android:width="2dp"/>
		<solid android:color="#FFFFFFFF" />
	</shape>
</item>
<item android:top="2dp" android:bottom="2dp"><!--Item 2-->
	<shape android:shape="rectangle">
		<solid android:color="#FFFFFFFF" />
	</shape>
</item>
</layer-list>

#How layer list works?

Layer One

<item><!--Item 1-->
	<shape android:shape="rectangle">
		<stroke android:color="@color/green" android:width="2dp"/>
		<solid android:color="#FFFFFFFF" />
	</shape>
</item>

Above code snippet results in a layer with border on all sides. Stroke tag defines the border and Solid tag defines the background colour.

#

Layer Two

<item android:top="2dp" android:bottom="2dp"><!--Item 2-->
	<shape android:shape="rectangle">
		<solid android:color="#FFFFFFFF" />
	</shape>
</item>

This snippet is drawn over the first layer which has top offset 2dp and bottom offset 2dp (border thickness)