Android Dial Phone Programmatically

Have you imagined your app can make a phone call for you directly? Yes, Android phone can do this for you easily with only a few steps!

Mind map for making a phone call directly and dialling a number

Android provides two ways to call a phone number from app — One is directing user to the keypad page of System “Phone” app and the another one is directly making a phone call for user. To provide a smoother user experience, the later method should be considered but developer should take care for the runtime permission (CALL_PHONE) carefully.

In this article, I would go through the steps and details to implement this flow.

Telephone URI Standard

Before start coding, there is an IETF standard defines the URI specification for a phone call. A phone call URI contains four parts:

1. Schema: tel: which defines this URI represents a telephone call
2. Preserved character: “+” which defines the start of the country code
3. Country code: Length ranges from 1 to 4 number, e.g. 852 represents Hong Kong
4. Phone number: Self-explanatory

Below is an example of telephone URI for a phone call to Hong Kong (+852) with phone number “1878200”. The overall URI is tel:+8521878200.

Method 1) Dial a number (Permission-free)

Mind map for dialling a phone number

Step 1:
We have to parse the readable telephone string to Uri object by the Uri.parse() function.

Step 2:
Set the Intent Action of Intent to Intent.ACTION_DIAL such that Android system can filter and delegate the dialling action to any app that can make a phone call.

Step 3:
Set the phone call URI to the Intent data in order to pass the phone number to the target phone call app.

Step 4:
Start an Activity that can accept making a phone call.

Method 2) Make a phone call directly

Mind map for making a phone call directly

The steps for making a phone call directly is similar to dialling a phone call except it requires a runtime permission CALL_PHONE and a new Intent Action Intent.ACTION_CALL (See line 15 of the above code).

CALL_PHONE permission is a dangerous runtime permission since it can instantiate a phone call directly without going through the Dialler user interface for the user to confirm the call.

To request CALL_PHONE permission, it is recommended to use the simple RxPermissions library which takes care the Activity lifecycle during requesting the permission. See line 6 to line 9 for the set up.

Summary

1. App can help user to make a phone call directly or dial a phone number at System Phone app.
2. Dialling a phone number is permission-free and easy to use. However, it is less user-friendly since it requires user to press the dial button to make a phone call.
3. Making a phone call directly requires a CALL_PHONE runtime permission but can provide a better user experience.
4. Telephone URI standard is defined by the IETF and consists of 4 parts, i.e. schema, preserved plus symbol, country code and phone number.

Reference

1. Android permission CALL_PHONE
2. IETF — The tel URI for Telephone Numbers

You are welcome to follow me at Twitter@myrick_chow for more information. Thank you for reading this article. Have a nice day! 😄