Add manifestPlaceholders feature

buildozer/default.spec

@@ -235,6 +235,12 @@ android.allow_backup = True
 # (str) XML file for custom backup rules (see official auto backup documentation)
 # android.backup_rules =
 
+# (str) If you need to insert variables into your AndroidManifest.xml file,
+# you can do so with the manifestPlaceholders property.
+# This property takes a map of key-value pairs. (via a string)
+# Usage example : android.manifest_placeholders = [myCustomUrl:\"org.kivy.customurl\"]
+# android.manifest_placeholders = [:]
+
 #
 # Python for android (p4a) specific
 #

buildozer/targets/android.py

@@ -897,6 +897,12 @@ class TargetAndroid(Target):
             cmd.append('--depend')
             cmd.append(gradle_dependency)
 
+        # support for manifestPlaceholders
+        manifest_placeholders = self.buildozer.config.getdefault('app', 'android.manifest_placeholders', '[:]')
+        if manifest_placeholders:
+            cmd.append('--manifest-placeholders')
+            cmd.append("{}".format(manifest_placeholders))
+
         cmd.append('--arch')
         cmd.append(self._arch)