工厂模式:顾名思义,工厂生产对象。
public class FactoryMode { private static Map<Integer, Fragment> sFragmentMap = new HashMap<>(); public static Fragment createFragment(int postition) { Fragment fragment = sFragmentMap.get(postition); if (null == fragment) { switch (postition) { case 0: fragment =new Fragment1(); break; case 1: fragment =new Fragment2(); break; case 2: fragment =new Fragment3(); break; case 3: fragment =new Fragment4(); break; } sFragmentMap.put(postition, fragment); } return fragment; } }抛去繁琐的new对象,只调用createFragment方法即可