java – Dagger 2:如果没有@ Provide-annotated方法,则无法提供
发布时间:2020-12-15 00:41:02 所属栏目:Java 来源:网络整理
导读:我刚刚开始学习dagger2,面对一个看起来像个bug的奇怪问题.这是模块: @Modulepublic class SimpleModule { @Provides Cooker providerCooker() { return new Cooker("tom","natie"); }} 零件: @Component(modules = SimpleModule.class)public interface Si
我刚刚开始学习dagger2,面对一个看起来像个bug的奇怪问题.这是模块:
@Module public class SimpleModule { @Provides Cooker providerCooker() { return new Cooker("tom","natie"); } } 零件: @Component(modules = SimpleModule.class) public interface SimpleComponent { void inject(DaggerTestActivity activity); } 接口: public interface CoffeeMaker { String makeCoffee(); } 执行: public class SimpleMaker implements CoffeeMaker { Cooker mCooker; @Inject public SimpleMaker(Cooker cooker) { this.mCooker = cooker; } @Override public String makeCoffee() { return mCooker.makeCoffee(); } } 电饭煲: public class Cooker { String name; String coffeeKind; public Cooker(String name,String coffeeKind) { this.name = name; this.coffeeKind = coffeeKind; } public String makeCoffee() { return name + "make" + coffeeKind; } } 咖啡机: public class CoffeeMachine { CoffeeMaker mMaker; @Inject public CoffeeMachine(CoffeeMaker coffeeMaker) { this.mMaker = coffeeMaker; } public String makeCoffee() { return mMaker.makeCoffee(); } } 只是它.我在活动中使用.这里面临奇怪的问题: @Inject CoffeeMachine mCoffeeMachine; 我从Dagger 2编译器得到的错误如下: Error:(14,10) com.wyyc.daggertest.CoffeeMaker cannot be provided without an @Provides-annotated method. com.wyyc.zqqworkproject.DaggerTestActivity.mCoffeeMachine [injected field of type: com.wyyc.daggertest.CoffeeMachine mCoffeeMachine] com.wyyc.daggertest.CoffeeMachine.<init>(com.wyyc.daggertest.CoffeeMaker coffeeMaker) 所有这些情况看起来都很奇怪,我想听听更有经验的Dagger 2用户的一些意见. 解决方法
您的CoffeeMachine需要CoffeeMaker.并且您已声明Dagger将通过使用@Inject注释构造函数来处理向CoffeeMachine提供依赖性.但达格说:
因为您没有在任何地方指定应如何创建CoffeeMaker对象. @Injecting SimpleMaker是不够的,因为SimpleMaker!= CoffeeMaker.因此,你必须明确指出,当Dagger想要CoffeeMaker时,然后向他提供SimpleMaker. 将您的模块更改为: @Module public class SimpleModule { @Provides Cooker providerCooker() { return new Cooker("tom","natie"); } @Provides CoffeeMaker provideCoffeeMaker(Cooker cooker) { return new SimpleMaker(cooker); } } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |