辛格尔顿在Android中 [英] Singleton in Android
问题描述
我按照这个链接，并成功地取得了单例类的机器人。 <一href="http://www.devahead.com/blog/2011/06/extending-the-android-application-class-and-dealing-with-singleton/">http://www.devahead.com/blog/2011/06/extending-the-android-application-class-and-dealing-with-singleton/
I have followed this link and successfully made singleton class in Android. http://www.devahead.com/blog/2011/06/extending-the-android-application-class-and-dealing-with-singleton/
问题是，我希望有一个单一的对象。像我有活动A和活动B.在活动AI获得从Singleton类的对象。我使用该对象并进行了一些修改。
Problem is that i want a single object. like i have Activity A and Activity B. In Activity A I access the object from Singleton class. I use the object and made some changes to it.
当我移动到活动B和访问从单例类的对象时，它给我的初始化的对象和不保留我在活动A.所做的更改 是否有任何其他的方式来保存的变化？ 请帮我专家。 这是MainActivity
When I move to Activity B and access the object from Singleton Class it gave me the initialized object and does not keep the changes which i have made in Activity A. Is there any other way to save the changing? Please help me Experts. This is MainActivity
public class MainActivity extends Activity {
protected MyApplication app;
private OnClickListener btn2=new OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent=new Intent(MainActivity.this,NextActivity.class);
startActivity(intent);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Get the application instance
app = (MyApplication)getApplication();
// Call a custom application method
app.customAppMethod();
// Call a custom method in MySingleton
Singleton.getInstance().customSingletonMethod();
Singleton.getInstance();
// Read the value of a variable in MySingleton
String singletonVar = Singleton.customVar;
Log.d("Test",singletonVar);
singletonVar="World";
Log.d("Test",singletonVar);
Button btn=(Button)findViewById(R.id.button1);
btn.setOnClickListener(btn2);
}
}
这是下一个活动。
公共类NextActivity延伸活动{
public class NextActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_next);
String singletonVar = Singleton.customVar;
Log.d("Test",singletonVar);
}}
单例类
public class Singleton
{
private static Singleton instance;
public static String customVar="Hello";
public static void initInstance()
{
if (instance == null)
{
// Create the instance
instance = new Singleton();
}
}
public static Singleton getInstance()
{
// Return the instance
return instance;
}
private Singleton()
{
// Constructor hidden because this is a singleton
}
public void customSingletonMethod()
{
// Custom method
}
}
和所有MyApplication
and MyApplication
public class MyApplication extends Application
{
@Override
public void onCreate()
{
super.onCreate();
// Initialize the singletons so their instances
// are bound to the application process.
initSingletons();
}
protected void initSingletons()
{
// Initialize the instance of MySingleton
Singleton.initInstance();
}
public void customAppMethod()
{
// Custom application method
}
}
当我运行此code，我得到你好，我在辛格尔顿当时的世界，我给它的主要活动已经初始化，并再次表明你好在接下来的活动中logcat中。 我希望它的下一个活动再次显示世界。 请帮我纠正。
When i run this code, i get Hello which i have initialized in Singleton then World which i gave it in Main Activity and again shows Hello in Next Activity in logcat. I want it to show world again in Next Activity. Please help me to correct this.
推荐答案
你能不能从你的code发布一个例子吗？
Could you post an example from your code ?
看看这个要点： https://gist.github.com/Akayh/5566992
它的工作原理，但它很快完成：
it works but it was done very quickly :
MyActivity：设置单首次+初始化mString在私有构造属性（你好），并显示该值（你好）
MyActivity : set the singleton for the first time + initialize mString attribute ("Hello") in private constructor and show the value ("Hello")
设置新的价值mString：单身
Set new value to mString : "Singleton"
启动activityB并显示mString值。 单身出现......
Launch activityB and show the mString value. "Singleton" appears...
这篇关于辛格尔顿在Android中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
