Add OnCompleteListener

Author: kengoon

sjfirebase/jinterface/oncomplete.py

@@ -0,0 +1,13 @@
+from jnius import PythonJavaClass, java_method
+
+
+class OnCompleteListener(PythonJavaClass):
+    __javainterfaces__ = ["com/google/android/gms/tasks/OnCompleteListener"]
+
+    def __init__(self, callback):
+        super().__init__()
+        self.callback = callback
+
+    @java_method('(Lcom/google/android/gms/tasks/Task;)V')
+    def onComplete(self, task):
+        self.callback(task.isSuccessful())