Forem: BalaKrishnan

Andriod Core Concepts

BalaKrishnan — Sun, 08 Mar 2020 06:50:44 +0000

I started to study the core of android few days back. I feel I am 1 year late to this. Ironically, You don't need to stretch too hard to find it. It is available in Android developer Documentation.
I would recommend you start from (1) Java memory allocation (2) Android Memory management (3) Linux memory management concepts.

## EasyCam

BalaKrishnan — Sat, 18 Jan 2020 16:32:15 +0000

EasyCam is Android Library that lets you easily integrate a camera feature in your app.

Goals of EasyCam's are

Easy implementation of the camera in the app
Easy Customization of camera view

This library handles all the logical parts internally and lets you implement a camera view within minutes. In this post, we will see how to integrate EasyCam by calling an Intent and EasyCamFragment - a way to customize your UI as we have handled all logics and memory handling in EasyCamFragment.

Here is the repo Link and Sample

By Intent

How does it work?

EasyCam has Capture and Preview page. The Capture page is where the user has a preview of the camera preview (you can look at the image below). Each UI component on this page is customizable. The preview page contains a preview of the image taken. You can go through the list of images you had captured and delete them if required.

It stores the images taken in the external directory as files and returns in onActivityResult callback.

EasyCam offers the following features

Screen orientation handling
Output image orientation handling
Front and Back camera support
Flash support
Single and multiple photoshoot mode
Set minimum and maximum count for multiple shoot mode
Preview of taken photos
Manual focus
Live preview in full screen or fit the aspect ratio
Delete option in multiple shoot mode

Add the dependency in module Gradle file

implementation 'in.balakrishnan.easycam:easycam:0.0.3-rc5'

implementation 'androidx.recyclerview:recyclerview:1.1.0'

implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0-rc03'

You can trigger the Camera Activity with the following code

        Intent intent = new Intent(this, CameraControllerActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
        intent.putExtra("inputData", new CameraBundleBuilder()
                .setFullscreenMode(false)
                .setDoneButtonString("Add")
                .setSinglePhotoMode(false)
                .setMax_photo(3)
                .setManualFocus(true)
                .setBucketName(getClass().getName())
                .setPreviewEnableCount(true)
                .setPreviewIconVisiblity(true)
                .setPreviewPageRedirection(true)
                .setEnableDone(false)
                .setClearBucket(true)
                .createCameraBundle());
        startActivityForResult(intent, 214);

You will get the result in the onActivityResult callback

   @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 214) {
            if (resultCode == RESULT_OK) {
                assert data != null;
                list = data.getStringArrayExtra("resultData");
            }
        }
    }

CameraBundleBuilder is a builder class used to configure the Camera View. With simple parameters, you will get the following screen

EasyCam Fragment

EasyCam Fragment contains all logic and configuration required for setting up a Camera View in your app.

To implement a simple camera view in your app. Extend EasyCamFragment instead of Fragment. There are three abstract functions you need to override.

getImageThumb() - You can get the thumbnail image of the captured image. The image is Low in size and quality. It is snap from texture view
getImage() - You can get an Original image using this function. The Image is high in size and quality. It is from Camera Source
setTextureResource() - You should return the Texture Id in this callback

How to trigger Image capture?

You can trigger image capture using takePicture() function in EasyCamFragment.

Customization

You can customize the following

Front and Back Camera selection
Flash type
Full-Screen
Manual Focus

Here is an example

Looking back at 2019

BalaKrishnan — Mon, 30 Dec 2019 08:49:46 +0000

2019 has been a year to remember for me. Here I have shared gist of things I have done in 2019

💭Developed app for

1 Android - Mobile
2 Android - Tab
3 Android TV
4 FireStick

📱Worked on different apps

Streaming app
Selling / Buying platform app
Wallpaper app - NFWalls
Tweetstorm - StormIt

👨‍💻Worked with

Kotlin
Coroutines
Dagger
Jetpack Components
- RoomDB
- WorkManager
- ViewModel
- LiveData
- Navigation component
Camera2 API
Multi module app
Instant app
Firebase
- RealTime DB
- Firebase Auth
- Firebase Dynamic link
- Firebase Analytics and distribution
- Firebase In-App messaging and Cloud messaging (Notification)
- Firebase Remote config
Maps
RxJava
Google drive API integration for backup and restore
DRM content streaming
Security
- SSL Pinning
- RSA content verification
- AES Encryption / Decryption
- Keystore to store sensitive data

🧗Updated

Moved an App from Java to Kotlin
Moved an App from ORM Lite to Room DB

Open source Contribution

RxJava - Make your Async Task Synchronous

BalaKrishnan — Fri, 18 Oct 2019 12:21:39 +0000

In Android framework, We have to do all the time consuming work in background thread. It sounds easy but believe me implementation is pain. If you are using kotlin you can use doAsync or Coroutine but if you are using RxJava you can achieve this without much changes in your code.

I have a use case where I have to download the given files in background using WorkManager. Well, here comes the pain, "We have to download all the images and then return success or failure or retry Result to the work manager". How do we hold the thread until Download is complete?
Initially I have solved this with the CountDownLatch, I implemented and got a working code with that. But it was messy code.

If you are using RxJava, We can do this with operator "blockingGet()" for this your Observable should be "Single".

https://gist.github.com/BalakrishnanPT/ea6281f15f5dc7882c2e74b3ec46b848