AvailMem.pas

uses
  Androidapi.JNI.App, Androidapi.Helpers, Androidapi.JNI.GraphicsContentViewText;

// Available memory in MB
function GetMemory: Int64;
var
  LMemoryInfo: JActivityManager_MemoryInfo;
  LActivityManager: JActivityManager;
begin
  LActivityManager := TJActivityManager.Wrap(JObjectToID(TAndroidHelper.Context.getSystemService(TJActivity.JavaClass.ACTIVITY_SERVICE)));
  LMemoryInfo := TJActivityManager_MemoryInfo.Create;
  LActivityManager.getMemoryInfo(LMemoryInfo);
  Result := Round(LMemoryInfo.availMem / $100000);
end;