接入Paging改写动态页面

Author: fmtcias

.idea/codeStyles/Project.xml

@@ -84,6 +84,10 @@ Model-View-ViewModel，View 指绿色的 Activity/Fragment，主要负责界面
    Glide相比起Fresco要轻量很多，api调用起来也很简洁，对图片加载要求不是很高的话建议使用Glide。
 
 # 更新日志
+### v2.0
+  * 接入Paging改写动态分页列表页面,并封装Paging版分页模版(BasePagingVMFragment、BaseLPagingModel)
+  * 提供Paging版分页列表模版以及普通版分页列表模版，方便对比学习
+  * 下个版本计划加入Navigation
 ### v1.9
   * 添加动态页面
   * 调整项目结构，优化代码

.idea/codeStyles/codeStyleConfig.xml

@@ -2,10 +2,21 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlin-kapt'
+apply plugin: 'kotlin-noarg'
+apply plugin: 'kotlin-allopen'
+
 kapt {
     generateStubs = true
 }
 
+allOpen {
+    annotation("com.fmt.github.Poko")
+}
+
+noArg {
+    annotation("com.fmt.github.Poko")
+}
+
 android {
     compileSdkVersion 28
     defaultConfig {
@@ -77,6 +88,9 @@ dependencies {
     kapt "androidx.room:room-compiler:2.2.5"
     implementation "androidx.room:room-ktx:2.2.5"
 
+    //paging
+    implementation "androidx.paging:paging-runtime-ktx:2.1.2"
+
     //koin(依赖注入)
     implementation "org.koin:koin-androidx-scope:2.0.1"
     implementation "org.koin:koin-androidx-viewmodel:2.0.1"

.idea/misc.xml

@@ -0,0 +1,78 @@
+package com.fmt.github.base.fragment
+
+import androidx.lifecycle.Observer
+import androidx.paging.PagedList
+import androidx.paging.PagedListAdapter
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.fmt.github.R
+import com.fmt.github.base.viewmodel.BaseLPagingModel
+import com.fmt.github.ext.yes
+import com.kennyc.view.MultiStateView
+import com.scwang.smartrefresh.layout.api.RefreshLayout
+import com.scwang.smartrefresh.layout.listener.OnLoadMoreListener
+import com.scwang.smartrefresh.layout.listener.OnRefreshListener
+import kotlinx.android.synthetic.main.common_refresh_recyclerview.*
+
+/**
+ * 基于Paging封装通用分页列表
+ */
+abstract class BasePagingVMFragment<M, VM : BaseLPagingModel<M>, VH : RecyclerView.ViewHolder> :
+    BaseVMFragment(), OnRefreshListener,
+    OnLoadMoreListener {
+
+    private val mAdapter: PagedListAdapter<M, VH> by lazy { getAdapter() }
+
+    lateinit var mViewModel: VM
+
+    override fun getLayoutRes(): Int = R.layout.common_refresh_recyclerview
+
+    override fun initView() {
+        mRefreshLayout.run {
+            setOnRefreshListener(this@BasePagingVMFragment)
+            setOnLoadMoreListener(this@BasePagingVMFragment)
+        }
+
+        mRecyclerView.layoutManager = LinearLayoutManager(mActivity)
+        mRecyclerView.adapter = mAdapter
+
+        mViewModel = getViewModel() as VM
+        mViewModel.mBoundaryData.observe(this, Observer {
+            it.yes {
+                mMultipleStatusView.viewState = MultiStateView.ViewState.CONTENT
+            }
+        })
+        mViewModel.loadMoreState.observe(this, Observer {
+            mRefreshLayout.setEnableLoadMore(it)//上拉加载进度条只有在Paging加载更多失败时才有效(用于规避Paging加载更多失败后，无法再次加载问题)
+        })
+
+        afterViewCreated()
+    }
+
+    override fun initData() {
+        mRefreshLayout.autoRefreshAnimationOnly()
+        mViewModel.pagedList.observe(this, Observer<PagedList<M>> {
+            mAdapter.submitList(it)
+        })
+    }
+
+    override fun onRefresh(refreshLayout: RefreshLayout) {
+        mViewModel.refresh()
+    }
+
+    override fun onLoadMore(refreshLayout: RefreshLayout) {
+        mViewModel.loadMoreRetry()
+    }
+
+    override fun dismissLoading() {
+        mRefreshLayout.run {
+            finishRefresh()
+            finishLoadMore()
+        }
+    }
+
+    abstract fun afterViewCreated()
+
+    abstract fun getAdapter(): PagedListAdapter<M, VH>
+
+}

.idea/vcs.xml

@@ -0,0 +1,96 @@
+package com.fmt.github.base.viewmodel
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.viewModelScope
+import androidx.paging.DataSource
+import androidx.paging.LivePagedListBuilder
+import androidx.paging.PageKeyedDataSource
+import androidx.paging.PagedList
+import com.fmt.github.config.Configs
+import kotlinx.coroutines.launch
+
+/**
+ * 基于Paging封装通用ViewModel
+ */
+abstract class BaseLPagingModel<M> : BaseViewModel() {
+
+    lateinit var mDataSource: PageKeyedDataSource<Int, M>
+
+    val mBoundaryData = MutableLiveData(false)//控制页面显示状态
+
+    val loadMoreState = MutableLiveData(false)
+
+    var loadMoreRetry: (() -> Unit)? = null
+
+    val pagedList: LiveData<PagedList<M>> by lazy {
+        LivePagedListBuilder<Int, M>(
+            object : DataSource.Factory<Int, M>() {
+                override fun create(): DataSource<Int, M> {
+                    mDataSource = PageDataSource()
+                    return mDataSource
+                }
+            }, PagedList.Config.Builder()
+                .setPageSize(Configs.PAGE_SIZE)
+                .setInitialLoadSizeHint(12)
+                .build()
+        ).build()
+    }
+
+    //真正加载数据的来源
+    inner class PageDataSource : PageKeyedDataSource<Int, M>() {
+        override fun loadInitial(
+            params: LoadInitialParams<Int>,
+            callback: LoadInitialCallback<Int, M>
+        ) {
+            launch {
+                val list = getDataList(1)
+                mBoundaryData.postValue(list.isNotEmpty())
+                callback.onResult(list, null, 2)
+            }
+        }
+
+        override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Int, M>) {
+            viewModelScope.launch {
+                try {
+                    mStateLiveData.value = LoadState
+                    val list = getDataList(params.key)
+                    callback.onResult(
+                        list,
+                        params.key + 1
+                    )
+                    mStateLiveData.value = SuccessState
+                    loadMoreState.postValue(false)
+                } catch (e: Exception) {
+                    mStateLiveData.value = ErrorState(e.message)
+                    loadMoreState.postValue(true)
+                    loadMoreRetry = {
+                        //保存加载更多失败时的场景
+                        loadMoreFail(params, callback)
+                    }
+                }
+            }
+        }
+
+        override fun loadBefore(params: LoadParams<Int>, callback: LoadCallback<Int, M>) {}
+    }
+
+    fun refresh() {//Paging刷新数据
+        mDataSource.invalidate()
+    }
+
+    fun loadMoreRetry() {//加载更多失败重试
+        loadMoreRetry?.invoke()
+    }
+
+    fun loadMoreFail(//加载更多失败时调用
+        params: PageKeyedDataSource.LoadParams<Int>,
+        callback: PageKeyedDataSource.LoadCallback<Int, M>
+    ) {
+        mDataSource.loadAfter(params, callback)
+    }
+
+    abstract suspend fun getDataList(page: Int): List<M>
+
+
+}

README.md

@@ -7,6 +7,7 @@ import com.fmt.github.BuildConfig
 import com.fmt.github.data.db.AppDataBase
 import com.fmt.github.data.http.interceptor.AuthorizationInterceptor
 import com.fmt.github.home.viewmodel.HomeViewModel
+import com.fmt.github.home.viewmodel.ReceivedEventViewModel
 import com.fmt.github.repos.api.ReposApi
 import com.fmt.github.repos.repository.ReposRepository
 import com.fmt.github.repos.viewmodel.ReposViewModel
@@ -28,17 +29,19 @@ private const val TAG = "fmt"
 
 val viewModelModule = module {
     viewModel { HomeViewModel(get()) }
+    viewModel { ReceivedEventViewModel(get()) }
     viewModel { ReposViewModel(get()) }
     viewModel { UserViewModel(get()) }
 }
 
 val reposModule = module {
+    //factory 每次注入时都重新创建一个新的对象
     factory { ReposRepository(get()) }
     factory { UserRepository(get(), get()) }
 }
 
 val remoteModule = module {
-
+    //single 单例对象
     single {
         val httpLoggingInterceptor = HttpLoggingInterceptor(object : HttpLoggingInterceptor.Logger {
             override fun log(message: String) {