Fix build

src/org/kde/kdeconnect/Backends/BaseLink.java

@@ -9,6 +9,7 @@ package org.kde.kdeconnect.Backends;
 import android.content.Context;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.WorkerThread;
 
 import org.kde.kdeconnect.Device;
@@ -45,7 +46,7 @@ public abstract class BaseLink {
         return getDeviceInfo().id;
     }
 
-    public abstract InetAddress getDeviceIp();
+    public abstract @Nullable InetAddress getDeviceIp();
 
     public BaseLinkProvider getLinkProvider() {
         return linkProvider;

src/org/kde/kdeconnect/Backends/BluetoothBackend/BluetoothLink.kt

@@ -21,6 +21,7 @@ import java.io.InputStream
 import java.io.InputStreamReader
 import java.io.OutputStream
 import java.io.Reader
+import java.net.InetAddress
 import java.util.UUID
 import kotlin.text.Charsets.UTF_8
 
@@ -98,6 +99,10 @@ class BluetoothLink(
         return theDeviceInfo
     }
 
+    override fun getDeviceIp(): InetAddress? {
+        return null;
+    }
+
     override fun disconnect() {
         if (connection == null) {
             return
@@ -159,4 +164,4 @@ class BluetoothLink(
             false
         }
     }
-}
+}

src/org/kde/kdeconnect/Backends/LoopbackBackend/LoopbackLink.kt

@@ -13,12 +13,16 @@ import org.kde.kdeconnect.Device
 import org.kde.kdeconnect.DeviceInfo
 import org.kde.kdeconnect.Helpers.DeviceHelper.getDeviceInfo
 import org.kde.kdeconnect.NetworkPacket
+import java.net.InetAddress
 
 class LoopbackLink : BaseLink {
     constructor(context: Context, linkProvider: BaseLinkProvider) : super(context, linkProvider)
 
     override fun getName(): String = "LoopbackLink"
     override fun getDeviceInfo(): DeviceInfo = getDeviceInfo(context)
+    override fun getDeviceIp(): InetAddress {
+        return InetAddress.getLoopbackAddress()
+    }
 
     @WorkerThread
     override fun sendPacket(packet: NetworkPacket, callback: Device.SendPacketStatusCallback, sendPayloadFromSameThread: Boolean): Boolean {