Step 1: Attach a text change listener

TextWatcher’s afterTextChanged method is called to notify you that, somewhere within EditText, the text has been changed.

If a text is changed and

• length is 1 that means typing is started,


• length is 0 means typing is stopped.

Sample android code:


Source: Github Applozic Android Chat SDK

Typing status should be stopped ina few others cases like:

i) If the app goes to background,

ii) EditText loses focus, or

iii) Typed text length remains same for some time duration.

Step 2: Publish and subscribe typing status of the user

It is time to send and receive typing status to the other device. This can be implemented using a publish-subscribe pattern. Let’s understand what is a publish-subscribe pattern..

Source: Wikipedia

Now, all we have to do is:

Subscribe user A’s app to a topic “/topic/user-a”, user B’s app to a topic “/topic/user-b” and publish the typing status to receiver’s topic.

	User A	User B
Subscribe	/topic/user-a	/topic/user-b
Publish	/topic/user-b	/topic/user-a
Typing started	1	1
Typing stopped	0	0

In order to send data from one device to another device in real time, we will require a socket based connection. There are many options available like Socket.io, Mosquitto.org, RabbitMQ.

For this tutorial, we will use RabbitMQ

Run RabbitMQ MQTT Adapter on your server.

On android, use the eclipse paho library to create mqtt client.

org.eclipse.paho.android.service–1.0.2.jar
org.eclipse.paho.client.mqttv3-1.0.2.jar

Above 2 versions for eclipse paho android client can be found here:

Android code to publish data:

Source: Github Applozic Android Chat SDK

Step Step 3: Update typing status real time on UI

At the receiver’s end, upon receiving typing status, show and hide the typing indicator accordingly.

Below is the android code to receive the typing status

More resourceful links:

Find typing indicator code in Applozic open source chat SDK available in GitHub.

for lightweight Android Chat SDK.

for lightweight iOS Chat SDK.

For iOS, you can use MQTT Client Framework for sending and receiving data from devices..

Reference:.

Build typing indicator in android

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