Remove db.close(); If you try another operation after closing the database, it will give you that exception. The documentation says: Releases a reference to the object, closing the object… Also, check out Android SQLite closed exception about a comment from an Android Framework engineer which states that it is not necessary to close the database … Read more
Josh Bloch recommends using a single-element enum type to implement singletons (see Effective Java 2nd Edition, Item 3: Enforce the singleton property with a private constructor or an enum type). Some people think this is a hack, since it doesn’t clearly convey intent, but it does work. The following example is taken straight from the … Read more
This question might be old but since this was the nearest answer I found when I had this problem I though I’d describe my solution. Using JUnit 4 Split your tests up so that there is one test method per class (this solution only changes classloaders between classes, not between methods as the parent runner … Read more
If I’m not wrong, you can cancel the closing event of that window and instead set visibility to hidden private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e) { e.Cancel = true; this.Visibility = Visibility.Hidden; }
(1) UPDATE 2019: ES7 Version class Singleton { static instance; constructor() { if (instance) { return instance; } this.instance = this; } foo() { // … } } console.log(new Singleton() === new Singleton()); (2) ES6 Version class Singleton { constructor() { const instance = this.constructor.instance; if (instance) { return instance; } this.constructor.instance = this; } … Read more
Yes, it has singleton pattern, Code to create a singleton object, public partial class Form2 : Form { ….. private static Form2 inst; public static Form2 GetForm { get { if (inst == null || inst.IsDisposed) inst = new Form2(); return inst; } } …. } Invoke/Show this form, Form2.GetForm.Show();
The standard singleton pattern is: final class Manager { static let shared = Manager() private init() { … } func foo() { … } } And you’d use it like so: Manager.shared.foo() Credit to appzYourLife for pointing out that one should declare it final to make sure it’s not accidentally subclassed as well as the … Read more
EntityManagerFactory instances are heavyweight objects. Each factory might maintain a metadata cache, object state cache, EntityManager pool, connection pool, and more. If your application no longer needs an EntityManagerFactory, you should close it to free these resources. When an EntityManagerFactory closes, all EntityManagers from that factory, and by extension all entities managed by those EntityManagers, … Read more
Because the class is now being injected with an IoC container, then why not use it to resolve all other dependencies too? Using the service locator pattern completely defeats one of the main points of dependency injection. The point of dependency injection is to make dependencies explicit. Once you hide those dependencies by not making … Read more
Update: 06-Mar-18 Use MyApplication instance instead of Context instance. Application instance is a singleton context instance itself. public class MyApplication extends Application { private static MyApplication mContext; @Override public void onCreate() { super.onCreate(); mContext = this; } public static MyApplication getContext() { return mContext; } } Previous Answer You can get the the application context … Read more