Android 无法从中提取存储的数据
下面是我的活动代码。我调用Android 无法从中提取存储的数据,android,Android,下面是我的活动代码。我调用setKey()来设置密钥,但是当我使用getKey()时,它返回” 似乎每次为SharedData创建新实例时 public class SharedData { // this is a singleton class that provides a global data private static SharedData instance = null; private SharedData
setKey()
来设置密钥,但是当我使用getKey()
时,它返回”
似乎每次为SharedData创建新实例时
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,您需要在下面几行中每次使用相同的实例:
SharedData data = SharedData.getInstance();
data.setKey("some string");//to set value
data.getKey(); //to get value
SharedData data = SharedData.getInstance();
data.setKey("some string");//to set value
data.getKey(); //to get value