android-iconify | Android integration of multiple icon providers | Icon library

I am unable to use the sample code to write to a GATT characteristic over BLE. I'm using the following code from Polidea's examples available here: https://github.com/Polidea/RxAndroidBle

Code:

rxBleDevice.establishConnection(false) .flatMapSingle(rxBleConnection - > rxBleConnection.writeCharacteristic(characteristicUUID, bytesToWrite)) .subscribe( characteristicValue - > { // Characteristic value confirmed. }, throwable - > { // Handle an error here. } );

IDE Errors:

App Level Gradle:

I tried to add Onesignal as Push Service to an App, but now i get following error after editing the build.gradle file.

ERROR: Could not get unknown property 'android' for root project 'android' of type org.gradle.api.Project.

Can someone tell me how to fix that? It's my first time editing an android project.

Thats my build.gradle(app) file:

My gradle is like bellow:

I'm using HashMap to fetch values for my listview adapter. The problem is that the last two elements of my HashMap are repeated. I have tried different solutions before posting this question. Some help would be highly appreciated, Thank you.

Here is the code for my HashMap

As per this answer and this answer I already make changes in app gradle but still it is showing me following error while building my application.

My gradle is bellow:

I have an apk with 31MBsize then I used from proguard and it is 30MB now.

Problem : When I upload apk on google play the size of apk increase to 57MB

What can I do ?

Here is my gradle :

I am getting the below error all of a sudden. The app was running fine till morning. Since then I have been getting this. I tried loading older commits from Git, however I am getting the same issue now. I can see that there's a duplicate entry of some class, but it is not very clear where. I have checked all of my libraries to locate the issue but in vain. Please help

I updated my android studio to :