CODEWITHSUNDEEP
javaandroidnullpointerexception
user8488823
user8488823

Reputation: 75

Android P WifiRttManager is always null

I recently installed this RTT-Manager-App on my Smartphone, mainly to find out if my device and the available Access Points support the IEEE 802.11mc standard.

However as soon as I start the app, it crashes. This is caused by a NullPointerException on the WifiRttManager instance. I then set up a tiny App which only contains this code in it's MainActivity:

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

    WifiRttManager rttManager = (WifiRttManager) getBaseContext().getSystemService(Context.WIFI_RTT_RANGING_SERVICE);
    rttManager.isAvailable();
}

This results in the same error: 

Unable to start activity ComponentInfo{...MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.net.wifi.rtt.WifiRttManager.isAvailable()' on a null object reference

WifiRttManager requires both Android P as well as a CPU that supports 802.11mc (such as Qualcomm Snapdragon 820 CPU, as stated by the author of the before mentioned RTT-Manager-App).

I first tried running the app on a OnePlus X (Android P and Qualcomm Snapdragon 801) where it crashed, so I thought that the CPU did not support 802.11mc.

However I then also tried running it on a OnePlus 6T (Android P and Qualcomm Snapdragon 845) where it crashed just the same.

What else could be the reason for getSystemService(Context.WIFI_RTT_RANGING_SERVICE) always returning null?

Upvotes: 1

Views: 1216

Answers (1)

JoonBLUE
JoonBLUE

Reputation: 51

It seems like your phone needs to be enabled to support wirirtt. According to the google document, https://source.android.com/devices/tech/connect/wifi-rtt

To implement Wi-Fi RTT, you must provide both framework and HAL/firmware support:

Framework:

AOSP code Enable Wi-Fi RTT: requires a feature flag Wi-Fi RTT (IEEE 802.11mc) HAL support (which implies firmware support)

To implement this feature, implement the Wi-Fi HIDL and enable the feature flag:

In device.mk located in device//, modify the PRODUCT_COPY_FILES environment variable to include support for the Wi-Fi RTT feature:

PRODUCT_COPY_FILES += frameworks/native/data/etc/android.hardware.wifi.rtt.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.hardware.wifi.rtt.xml

Otherwise, everything required for this feature is included in AOSP.

Upvotes: 1

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