1.使用Hilt实现快速依赖注入

1.1 导入依赖

  //hilt依赖
    //Hilt
    implementation("com.google.dagger:hilt-android:2.44")
    annotationProcessor("com.google.dagger:hilt-android-compiler:2.44")

1.2 在build.gradle(app)中加入插件

plugins {
    id("com.android.application")
    id("dagger.hilt.android.plugin")//hilt插件
}

1.3 在build.gradle(project)中加入classpath 

// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
    id("com.android.application") version "8.1.4" apply false
}

buildscript{
    dependencies{
         classpath("com.google.dagger:hilt-android-gradle-plugin:2.44")
   }
}

1.4 创建自定义Applciation

package com.tiger.hilt;

import android.app.Application;

import dagger.hilt.android.HiltAndroidApp;

@HiltAndroidApp //生成相应的组件
public class MyApplication extends Application {
}

1.5 将自定义Application添加到 清单文件

1.6 将要注入的类

package com.tiger.hilt;

import javax.inject.Inject;

public class User {
    //把对象实例的获取称之为绑定

    @Inject
    public User(){

    }
}

1.7 activity

package com.tiger.hilt;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;

import javax.inject.Inject;

import dagger.hilt.android.AndroidEntryPoint;
import dagger.hilt.android.HiltAndroidApp;

@AndroidEntryPoint
public class MainActivity extends AppCompatActivity {


    @Inject
    User user;


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

        Log.d("ning",user.toString());


    }
}

注入成功 

2.Hilt 的优势

3.在Hilt 中使用Module

package com.tiger.hilt;

import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;
import dagger.hilt.InstallIn;
import dagger.hilt.android.components.ActivityRetainedComponent;
import dagger.hilt.android.internal.managers.ApplicationComponentManager;
import dagger.hilt.components.SingletonComponent;

@InstallIn(SingletonComponent.class)//Application作用域
@Module
public class AppModule {

    @Singleton
    @Provides
    User providerUser(){
        return new User();
    }



}

package com.tiger.hilt;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;

import javax.inject.Inject;

import dagger.hilt.android.AndroidEntryPoint;
import dagger.hilt.android.HiltAndroidApp;

@AndroidEntryPoint
public class MainActivity extends AppCompatActivity {


    @Inject
    User user;

    @Inject
    User user2;

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

        Log.d("ning",user.toString());
        Log.d("ning",""+(user==user2));

    }
}

4.默认标准组件

ApplicationComponent新版本变成 

SingletonComponent

5.限定符注入Context

    @Inject//默认是ApplicationComponent
    public ViewModel(User user, Application application,Activity activity,@ApplicationContext Context context) {
        this.user = user;
        this.application = application;
        this.activity = activity;
        this.context = context;
    }

    @Inject//默认是ApplicationComponent
    public ViewModel(User user, Application application,Activity activity,@ActivityContext Context context) {
        this.user = user;
        this.application = application;
        this.activity = activity;
        this.context = context;
    }

6.Hilt 对 ViewModel的支持

6.1导入依赖

    //hilt依赖
    //Hilt
    implementation("com.google.dagger:hilt-android:2.44")
    annotationProcessor("com.google.dagger:hilt-android-compiler:2.44")

    //JetPack hilt 支持
    implementation("androidx.hilt:hilt-lifecycle-viewmodel:1.0.0-alpha03")
    annotationProcessor("androidx.hilt:hilt-comiler:1.0.0-alpha03")

plugins {
    id("com.android.application")
    id("dagger.hilt.android.plugin")//hilt插件
}

buildscript{
    dependencies{
        classpath("com.google.dagger:hilt-android-gradle-plugin:2.44")
    }
}

这里有点问题，以后在用Kotlin是另一套，这里主要了解使用流程，和核心思想！