Android Singleton

Question

Class MyApplication is created :


    public class MyApplication extends Application {  // code - freeCodeCamp.org 
    
        private static MyApplication singleton;
        private List<Location> myLocations;
    
    
        public List<Location> getMyLocations() {
            return myLocations;
        }
    
        public void setMyLocations(List<Location> myLocations) {
            this.myLocations = myLocations;
        }
    
        public MyApplication getInstance(){
            return singleton;
        }
    
        public void OnCreate() {
            super.onCreate();
            singleton = this;
            myLocations = new ArrayList<>();
        }
    }

    MyApplication myApplication = (MyApplication)getApplicationContext();
    savedLocations = myApplication.getMyLocations();
    savedLocations.add(currentLocation);

currentLocation具有有效的位置值。有什么提示吗？谢谢

Answer 1

MyLocations为null，因为您拼错了onCreate方法签名，而且实际上从未调用过它。

您应该更改以下内容：

public void OnCreate() {

对此：

@Override
public void onCreate() {