普通类，单例类或静态方法以提高性能

Question

In my application I've a class called AppUtils.java , which basically contains utility functions like covertDpToPx() , UrlEncoder()` etc.

Issue is this class, apart from normal Activities , can also be called by Services running constanly in background.

So, how should I design this class from performance point-of-view?

Thank You

Answer 1

The good practice for an utility class is to make it final to disable inheritance, make constructor private to prevent instantiation and provide a set of public static utility methods:

public final class AppUtils {

    private AppUtils() {
    }

    public static float covertDpToPx() {
        ...
    }

    public static String encodeUrl(String url) {
        ...
    }
}

Answer 2

根据Android性能提示， Google建议在Android上使用static over singleton或virtual

Answer 3

如果可能，请将所有方法设为静态，以防万一将构造函数声明为私有，以免您意外创建该类的实例。