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Mvvm 的简单封装使用

Mvvm的封装我采用的是kotlin + ARouter + Retrofit + MvvM方式进行封装,实现一个app的基本开发需求,包括:分包、快速开发、网络请求、框架集合等。如下,介绍一些封装的基础组件,详细代码模本可参考我的开源工程。

LiveData

界面实现

  1. 界面实现是通过反射创建基类BaseMvvmActivity、BaseMvvmFragment,如下:
    abstract class BaseMvvmFragment<in T: ViewDataBinding, V: ViewModel>() : BaseFragment(){

        /**
         * 泛型占位符
         */
        private  val tClass:Class<T>
        private  val vClass:Class<V>
        constructor(layoutId:Int):this()


        init {
            val type = javaClass.genericSuperclass
            val types = (type as ParameterizedType).actualTypeArguments
            tClass = types[0] as Class<T>
            vClass = types[1] as Class<V>
        }

        /**
         * 数据绑定生成类
         */
        private lateinit var viewBinding:T

        /**
         * 数据操作ViewModel
         */
        protected lateinit  var viewModel: V

        override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
            activity?.let {
                if (it is AppCompatActivity){
                    viewModel =  it.obtainViewModel(vClass).also { viewModel ->
                        observe(viewModel)
                    }
                }
            }
            val method = tClass.getMethod("inflate", LayoutInflater::class.java,ViewGroup::class.java,
                Boolean::class.java)
            method.isAccessible =true
            viewBinding=  (method.invoke(null,layoutInflater,container,false) as T).apply {
                val objClass = javaClass
                try{
                    val mt =   objClass.methods.last {
                        it.name.startsWith("set") && it.parameterTypes.size==1 && it.parameterTypes[0] == vClass
                    }

                    mt?.isAccessible = true
                    mt.invoke(this,viewModel)
                }catch (e: Exception){
                    e.printStackTrace()
                    LogUtils.e("获取viewModel异常:${e.message}")
                }
                lifecycleOwner = viewLifecycleOwner
            }
            val view = viewBinding.root
            init(view)
            return view
        }

        /**
         *
         * 数据监听回调
         * @param v 绑定的viewModel
         */
        abstract fun observe(v:V)

        /**
         * 重写初始化UI或者data,非必要
         */
       open fun init(view:View)=Unit

    }
  1. recyclerview adapter基类
    abstract class BaseAdapter<T,V: ViewDataBinding>(@LayoutRes val layoutResId:Int,list:List<T>?=null):
            BaseQuickAdapter<T, BaseHolder<V>>(layoutResId,list) {

        override fun convert(helper: BaseHolder<V>?, item: T) {
            observe(helper?.binding,helper,item)
        }


        abstract fun observe(v:V?, helper: BaseHolder<V>?, item: T)
    }


    class BaseHolder<V: ViewDataBinding>(val view: View): BaseViewHolder(view){

        var binding:V = DataBindingUtil.bind<V>(view)!!.apply{
            executePendingBindings()
        }
    }
  1. viewModle 实现基类
    abstract class BaseViewModel<T> : ViewModel() {

        /**
         * 网络请求泛型占位符
         */
        private  val tClass:Class<T>?
        val resp: RepositoryImpl = ViewModelFactory.getInstance().repository
        init {
            val type = javaClass.genericSuperclass
            val types = (type as ParameterizedType).actualTypeArguments
            tClass = types[0] as Class<T>
        }

        /**
         * 网络请求api
         */
        val api:T? by lazy {
            tClass?.let {
                RetrofitFactory.instance.create(tClass)
            }
        }

        companion object {

            @BindingAdapter("app:imageUrl")
            @JvmStatic
            fun loadImage(imageView: ImageView, url: String) {
                Glide.with(imageView.context).load(url).into(imageView)
            }

        }

    }

  1. 网络请求使用 网络请求可直接创建retrofit 的api接口类,直接在viewModel调用请求
    interface TestApi {

       @GET("/test")
       fun getTest():CallAdapterLiveData<BaseResp<TestData>>

    }


    //ViewModel
    class TestViewModel : BaseViewModel<TestApi>(){

      fun initData(){
        lifecycleObserver?.apply {
               api?.getTest()?.observe(this, Observer {

                   it.success {
                       //成功返回数据
                   }.error {  
                      //返回数据异常
                   }
               })

           }
      }
    }
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