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首页 > 解决方案 > 安卓|| 在 Hilt 不支持的类中注入依赖项，例如 Helper 类

java - 安卓|| 在 Hilt 不支持的类中注入依赖项，例如 Helper 类

问题描述

我在我的应用程序中使用了 Hilt，我成功地在 Activity 类中注入了依赖项并获得了所需的结果，但无法在其他类中注入依赖项，例如辅助类。

请检查我在MainActivity类下面尝试过的以下代码

package com.inn.hiltdemo;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import com.inn.hiltdemo.hilt.MyFirstHelperClass;

import javax.inject.Inject;
import javax.inject.Named;

import dagger.hilt.android.AndroidEntryPoint;

@AndroidEntryPoint
public class MainActivity extends AppCompatActivity {


    @Inject
    @Named("MyHelperClass")
    MyFirstHelperClass myFirstHelperClass;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ////IT IS RUNNING SUCCESSFULLY
        System.out.println("HERE IS THE HELPER CLASS DATA==>>>> "+ myFirstHelperClass.getStringData());


        MySecondHelperClass mySecondHelperClass = new MySecondHelperClass();
        mySecondHelperClass.getSecondaryDataFromHelper(this);

    }
}

我的MyModule课程

package com.inn.hiltdemo.hilt

import dagger.Module
import dagger.Provides
import dagger.hilt.InstallIn
import dagger.hilt.components.SingletonComponent
import javax.inject.Named
import javax.inject.Singleton

@Module
@InstallIn(SingletonComponent::class)
class MyModule {

    @Singleton
    @Provides
    @Named("MyHelperClass")
    fun provideMyHelperClass(): MyFirstHelperClass {
        return MyFirstHelperClass()
    }
}

请检查MyFirstHelperClass类

 package com.inn.hiltdemo.hilt;

public class MyFirstHelperClass {

    public String getStringData() {
        return "My Data";
    }
}

这是我的MySecondHelperClass.java，我试图在其中获取Hilt依赖注入，请检查以下代码。

 package com.inn.hiltdemo;
    
    import android.content.Context;
    
    import com.inn.hiltdemo.hilt.MyFirstHelperClass;
    
    import javax.inject.Singleton;
    
    import dagger.hilt.EntryPoint;
    import dagger.hilt.InstallIn;
    import dagger.hilt.android.EntryPointAccessors;
    import dagger.hilt.components.SingletonComponent;
    
    @Singleton
    public class MySecondHelperClass {
    
    
        @EntryPoint
        @InstallIn(SingletonComponent.class)
        interface DeviceDiagnosticHelperEntryPoint {
            public MyFirstHelperClass provideMyFirstHelperClass();
        }
    
        public void getSecondaryDataFromHelper(Context mContext) {
    
            Context appContext = mContext.getApplicationContext();
            DeviceDiagnosticHelperEntryPoint hiltEntryPoint =
                    EntryPointAccessors.fromApplication(appContext,
                            DeviceDiagnosticHelperEntryPoint.class);
            MyFirstHelperClass myFirstHelperClass =
                    hiltEntryPoint.provideMyFirstHelperClass();
    
            System.out.println("HERE WE CAN USE==>>>> " + myFirstHelperClass.getStringData());
    
    
        }
    
    
    }

从MySecondHelperClass.java，我想在我的上面的类中进行依赖注入但是得到如下异常

[Dagger/MissingBinding] com.inn.hiltdemo.hilt.MyFirstHelperClass 不能在没有 @Inject 构造函数或 @Provides-annotated 方法的情况下提供。在 com.inn.hiltdemo.MySecondHelperClass.DeviceDiagnosticHelperEntryPoint.provideMyFirstHelperClass() 请求 com.inn.hiltdemo.hilt.MyFirstHelperClass

标签： javaandroidandroid-studioandroid-activitydagger-hilt

解决方案

您在第二个 Helper 中错过了 @Named 注释：

public class MySecondHelperClass {

   @EntryPoint
   @InstallIn(SingletonComponent.class)
   interface DeviceDiagnosticHelperEntryPoint {
       @Named("MyHelperClass")
       MyFirstHelperClass provideMyFirstHelperClass();
   }

   public void getSecondaryDataFromHelper(Context mContext) {

       Context appContext = mContext.getApplicationContext();
       DeviceDiagnosticHelperEntryPoint hiltEntryPoint =
               EntryPointAccessors.fromApplication(appContext,
                       DeviceDiagnosticHelperEntryPoint.class);
       MyFirstHelperClass myFirstHelperClass =
               hiltEntryPoint.provideMyFirstHelperClass();

       System.out.println("HERE WE CAN USE==>>>> " + 
       myFirstHelperClass.getStringData());
   }
}

第二种选择是MyFirstHelperClass用注入注释的构造函数并完全删除 Module 类（如果MyFirstHelperClass是你的）

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