Serkan,
There was a client bug that may still exist on Android where the action target for an embedded image would be ignored by the client, causing the action to fail. You can work around this bug by creating a wrapper action that contains a single sub-action step that calls your real action with the correct target.
So create an action called ShowActivityDetailWrapper that has a singe sub-action step that calls ShowActivityDetail with your target. This wrapper action should not accept any object type. Tie this wrapper action to the embedded image.
Jason Latko - Senior Product Developer at SAP
