Dagger2 +ButterKnife 框架集成和运用

Dagger2 是一个注入框架 ：简单说就是 对象注入 以前要new 的东西，现在通过Dagger2 直接提供 实现了一定程度的解耦合

一 环境配置 

  dependencies {
        classpath 'com.android.tools.build:gradle:2.3.3'

        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }

全文如下不细说，注意Butterknife 的原始自动生成代码用的  不是Apt  所以会发生冲突 将他的改成这样就都可以用了

apply plugin: 'com.android.application'
apply plugin: 'com.jakewharton.butterknife'
apply plugin: 'com.neenbedankt.android-apt'
android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "com.example.cuizehui.estore"
        minSdkVersion 19
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    //dagger2和butterknife冲突
    packagingOptions{
        exclude 'META-INF/services/javax.annotation.processing.Processor'
    }

}

dependencies {
    apply plugin: 'com.neenbedankt.android-apt'


    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })


   /* apt 'com.google.dagger:dagger-compiler:2.10-rc4'
*/
    //dagger2
    apt 'com.google.dagger:dagger-compiler:2.0'
    compile 'com.google.dagger:dagger:2.0'


    compile 'com.android.support:appcompat-v7:26.+'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support:design:26.+'
    compile 'com.android.support:support-v4:26.+'

    //butterknife
    compile 'com.jakewharton:butterknife:8.8.1'
    /*annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'
*/
    //只需要改这一句
    apt 'com.jakewharton:butterknife-compiler:+'

    // circleimagerview
    compile 'de.hdodenhof:circleimageview:2.1.0'

    testCompile 'junit:junit:4.12'
    provided 'org.glassfish:javax.annotation:10.0-b28'
}

二 根据框架结构分三层

 Application  -->Activity --> view/fragment  大多数情况下都是这三层

参考文章：

http://www.jianshu.com/p/f4180ad30317

1

Application:  (因为ApplictionComponent 是Activity 的依赖项所以 在生成其他Component 时 需要依赖项的对象)

APPComponet的创建:

public class MyApplication extends Application
{
   
    //全局单例 注入器 并给其他注入器提供依赖
    private ApplicationComponent appComponent;

        @Override
        public void onCreate() {
            super.onCreate();
            initAppComponent();

        }


    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;

    }


    public  void  initAppComponent(){

        appComponent= DaggerApplicationComponent
                .builder()
                .applicationModule(new ApplicationModule(this))
                .build();
    }
    public static MyApplication getInstance(Context context){
        return (MyApplication)context.getApplicationContext();
    }


    public ApplicationComponent getAppComponent(){
            return  appComponent;
    }


}

AppComponent 文件（是一个接口文件 加注释 因为这里使用了单例模式所以依赖项后面要加作用范围 也就是作用域@注解）：

package com.example.cuizehui.estore.interfaces;

import android.app.Application;

import com.example.cuizehui.estore.MainActivity;
import com.example.cuizehui.estore.module.ApplicationModule;


import javax.inject.Singleton;

import dagger.Component;

/**
 * Created by cuizehui on 17-9-13.
 * * 注入器
 */
@Singleton
@Component (modules = ApplicationModule.class)
public interface ApplicationComponent {

    Application getApplication();

}

AppModule:文件 只是简单的提供了一个APP对象

package com.example.cuizehui.estore.module;

import android.app.Application;

import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;

@Module
public class ApplicationModule {


    private Application application;

    public ApplicationModule(Application application){
        this.application=application;
    }

    @Provides
    @Singleton
    public Application provideApplication(){
        return application;
    }

}

2

MainActivity:

MainActivityComponet(由于前面的单例依赖项后面要加作用范围 也就是作用域@PreActivity):

package com.example.cuizehui.estore.interfaces;

import com.example.cuizehui.estore.MainActivity;

import com.example.cuizehui.estore.PreActivity;
import com.example.cuizehui.estore.module.MainActivityModule;

import dagger.Component;

/**
 * Created by cuizehui on 17-9-14.
 *
 */
@PreActivity
@Component (modules = MainActivityModule.class,dependencies = ApplicationComponent.class)
public interface MainActivityComponent {
    void inject(MainActivity mainActivity);
}

PreActivity():

package com.example.cuizehui.estore;

import javax.inject.Scope;

@Scope
public @interface PreActivity {
}

MainActivityModule:(这里实现了对一个listview adapter对象的创建和提供)

package com.example.cuizehui.estore.module;

import android.util.Log;

import java.util.ArrayList;

import dagger.Module;
import dagger.Provides;


@Module

public class MainActivityModule {

    //mainActivity 引用的获取  ,方便fragment  获取
    private   MainActivity mainActivity;

    public MainActivityModule(MainActivity mainActivity) {

        this.mainActivity=mainActivity;

    }

    @Provides
    @PreActivity

    MainActivity provideMainActivity() {
        return mainActivity;
    }

    @PreActivity
    @Provides
    public ArrayList<BasePagerView> providePagerViews(){

        ArrayList<BasePagerView>   pagerViews=new ArrayList<>();
        pagerViews.add(new HomepagerView(mainActivity));
        pagerViews.add(new ShopPagerView(mainActivity));
        pagerViews.add(new OrderPagerView(mainActivity));
        pagerViews.add(new MinePagerView(mainActivity));

        return  pagerViews;
    }

    //通过参数的方法 也能进入到上面的代码 获取到对象 ，另外这段代码可以省略和直接在在MainViewPagerAdapter的构造函数中添加注解的效果一至
    @PreActivity
    @Provides
    public MainViewPagerAdapter providemainViewPagerAdapter(ArrayList<BasePagerView> pagerViewslist){
        MainViewPagerAdapter mainViewPagerAdapter=new MainViewPagerAdapter(pagerViewslist);
        return  mainViewPagerAdapter;
    }



}

MainActivityComponet的注入（在MainAcitivity中完成）：

   MainActivityComponent  mainActivityComponent= DaggerMainActivityComponent
                .builder()
                .applicationComponent(appComponent)
                .mainActivityModule(new MainActivityModule(this))
                .build();
        mainActivityComponent.inject(this);

这样的注入也可以在BaseActivity 中写好了接口方便 继承BaseActivity的Activity 进行注入，像这样：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_base);
        setupActivityComponent(MyApplication.getInstance(this).getAppComponent());
    }



    protected abstract  void setupActivityComponent(ApplicationComponent appComponent);

3

view （普通类）注入

viewModule:

package com.example.cuizehui.estore.module;

import android.content.Context;
import android.util.Log;

import java.util.ArrayList;

import dagger.Module;
import dagger.Provides;

/**
 * Created by cuizehui on 17-9-19.
 */
@Module

public class HomepagerViewModule {
    public MainActivity mainActivity;
    public HomepagerViewModule(MainActivity mainActivity) {
        this.mainActivity=mainActivity;
    }



    @Provides
    public ArrayList<ShopDaTa> provideShopDaTa(){
        ArrayList<ShopDaTa> arrayList=new ArrayList<>();
        //请求拉取数据放到 arraylist中
        //模拟数据
        ShopDaTa shopDaTa1=new ShopDaTa();
        shopDaTa1.setProductName("dfsfd");

        ShopDaTa shopDaTa2=new ShopDaTa();
        shopDaTa1.setProductName("df43fd");
        arrayList.add(shopDaTa1);
        arrayList.add(shopDaTa2);



        return  arrayList ;
    }

    @Provides

    public HomeViewpagerLVAdapter provideLVadpter(ArrayList<ShopDaTa> arrayList){
        Log.d("list.size:",arrayList.size()+"");
        HomeViewpagerLVAdapter homeViewpagerLVAdapter=new HomeViewpagerLVAdapter(arrayList,mainActivity);

        return  homeViewpagerLVAdapter;
    }
}

viewComponet:

package com.example.cuizehui.estore.interfaces;

import dagger.Component;

@Component(modules = HomepagerViewModule.class)
public interface HomePagerViewComponent {
    //注入方法
    void inject(HomepagerView homepagerView);

}

viewComponet 在view中注入：

        HomePagerViewComponent homePagerViewComponent= DaggerHomePagerViewComponent
                .builder()
                .homepagerViewModule(new HomepagerViewModule(mainActivity))
                .build();
        homePagerViewComponent.inject(this);

特别要注意注入一定要在使用之前，还需要注意所传的上下文之间的引用！！

参考文章：

Dagger2 入门：

http://www.jianshu.com/p/1d84ba23f4d2

http://www.jianshu.com/p/cd2c1c9f68d4

Dagger2 封装：

http://blog.youkuaiyun.com/u012702547/article/details/52200927

http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2015/0519/2892.html

三 ButterKnife在viewHolder下的bind

.........

 @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ShopDaTa shopDaTa= shopDATAsarrayList.get(i);


        LayoutInflater layoutInflater=LayoutInflater.from(context);
        ViewHolder holder;

        if (view != null) {
            holder = (ViewHolder) view.getTag();
        }
        else {

            view =layoutInflater.inflate(R.layout.shop_data_layout,null);
            holder = new ViewHolder(view);

         //   holder.textView =view.findViewById(R.id.productName_tV);

            view.setTag(holder);
        }

        holder.textView.setText(shopDaTa.getProductName().toString());

        return view;

    }
    //在holder中绑定
    static class ViewHolder {
         @BindView(R.id.productName_tV)
         TextView textView;
        public ViewHolder(View view) {
           ButterKnife.bind(this, view);
        }
    }

参考文章：

http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2015/0519/2892.html