Question

以下是我的活动代码。我致电setKey()来设置密钥，但当我使用getKey()时，它会返回"";

public class SharedData {
    // This is a singleton class that provides a global data
    private SharedData instance = null;

    private SharedData() {
    }

    // Data to be shared
    private String key = "";

    public static SharedData getInstance() {
        instance = new SharedData();
        return instance;
    }

    public String getKey() {
        return key;
    }

    public void setKey(String skey) {
        key = skey;
    }
}

Answer 1

似乎每次都是每次为SharedData创建新实例

  public class SharedData {

        // this is a singleton class that provides a global data        
        private static SharedData instance = null;

        private SharedData() {

        }

        // data to be shared
        private String key = "";

        public static SharedData getInstance() {
            if (null == instance) {
            instance = new SharedData();
        }

        return instance;
        }


        public String getKey() {
            return key;
        }

        public void setKey(String skey) {
            key = skey;
        }
    }

现在你需要在每行下面的行中使用相同的实例：

SharedData data = SharedData.getInstance();
data.setKey("some string");//to set value
data.getKey(); //to get value

无法从中获取存储的数据

1 个答案: