加入对协程取消异常的处理

Author: fmtcias

app/src/main/java/com/fmt/github/base/viewmodel/BaseViewModel.kt

@@ -1,33 +1,45 @@
 package com.fmt.github.base.viewmodel
 
 import androidx.lifecycle.*
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.*
+
+//类型别名
+typealias LaunchBlock = suspend CoroutineScope.() -> Unit
+
+typealias EmitBlock<T> = suspend LiveDataScope<T>.() -> T
+
+typealias Cancel = (e: Exception) -> Unit
 
 open class BaseViewModel : ViewModel() {
 
     val mStateLiveData = MutableLiveData<StateActionEvent>()//通用事件模型驱动(如：显示对话框、取消对话框、错误提示)
 
-    fun launch(block: suspend CoroutineScope.() -> Unit) {//使用协程封装统一的网络请求处理
+    fun launch(cancel: Cancel? = null, block: LaunchBlock) {//使用协程封装统一的网络请求处理
         viewModelScope.launch {
             //ViewModel自带的viewModelScope.launch,会在页面销毁的时候自动取消请求,有效封装内存泄露
             try {
                 mStateLiveData.value = LoadState
                 block()
                 mStateLiveData.value = SuccessState
             } catch (e: Exception) {
-                mStateLiveData.value = ErrorState(e.message)
+                when (e) {
+                    is CancellationException -> cancel?.invoke(e)
+                    else -> mStateLiveData.value = ErrorState(e.message)
+                }
             }
         }
     }
 
-    fun <T> emit(block: suspend LiveDataScope<T>.() -> T): LiveData<T> = liveData {
+    fun <T> emit(cancel: Cancel? = null, block: EmitBlock<T>): LiveData<T> = liveData {
         try {
             mStateLiveData.value = LoadState
             emit(block())
             mStateLiveData.value = SuccessState
         } catch (e: Exception) {
-            mStateLiveData.value = ErrorState(e.message)
+            when (e) {
+                is CancellationException -> cancel?.invoke(e)
+                else -> mStateLiveData.value = ErrorState(e.message)
+            }
         }
     }
 }

app/src/main/java/com/fmt/github/ext/XPopupExt.kt

@@ -11,7 +11,8 @@ import kotlin.coroutines.resume
 
 //回调转协程
 suspend fun showConfirmPopup(context: Context, title: String, message: String) =
-    suspendCancellableCoroutine<Boolean> { continuation -> //Continuation(本质还是回调接口),kotlin编译器的黑魔法帮我们做了封装处理了
+    suspendCancellableCoroutine<Boolean> { continuation ->
+        //Continuation(本质还是回调接口),kotlin编译器的黑魔法帮我们做了封装处理了
         XPopup.Builder(context)
             .asConfirm(
                 title,
@@ -23,7 +24,8 @@ suspend fun showConfirmPopup(context: Context, title: String, message: String) =
                 false
             )
             .show().also { popupView ->
-                continuation.invokeOnCancellation {//在协程取消时，隐藏对话框
+                continuation.invokeOnCancellation {
+                    //在协程取消时，隐藏对话框
                     popupView.dismiss()
                 }
             }

app/src/main/java/com/fmt/github/home/work/DownLoadWork.kt

@@ -72,13 +72,10 @@ class DownLoadWork(context: Context, params: WorkerParameters) : CoroutineWorker
         }.otherwise {
             try {
                 initNotification()
-                withContext(Dispatchers.IO) {
-                    //withContext进行线程切换
-                    val responseBody =
-                        DownloadService.download(inputData.getString(DOWN_LOAD_URL).toString())
-                    startDown(responseBody.byteStream(), responseBody.contentLength())
-                    Result.success()
-                }
+                val responseBody =
+                    DownloadService.download(inputData.getString(DOWN_LOAD_URL).toString())
+                startDown(responseBody.byteStream(), responseBody.contentLength())
+                Result.success()
             } catch (e: Exception) {
                 mNotificationManager.cancel(NOTIFY_ID)
                 withContext(Dispatchers.Main) {

app/src/main/java/com/fmt/github/user/activity/UserInfoActivity.kt

@@ -55,6 +55,7 @@ class UserInfoActivity : BaseDataBindActivity<ActivityUserInfoBinding>() {
                 supportFragmentManager, this,
                 FragmentStatePagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
             )
+            mViewPager.offscreenPageLimit = 2
             mTabLayout.setupWithViewPager(mViewPager)
         }
     }

app/src/main/java/com/fmt/github/user/viewmodel/UserViewModel.kt

@@ -11,6 +11,7 @@ import com.fmt.github.user.repository.UserRepository
 
 class UserViewModel(private val mUserRepository: UserRepository) : BaseViewModel() {
 
+    //提供给xml文件进行绑定
     val mUserInfoModel = MutableLiveData<UserInfoModel>()
 
     fun createOrGetAuthorization(): LiveData<AuthorizationRespModel> = emit {
@@ -44,11 +45,10 @@ class UserViewModel(private val mUserRepository: UserRepository) : BaseViewModel
         mUserRepository.searchUsers(query, sort, order, page).items
     }
 
-    fun getUserInfo(user: String): LiveData<UserInfoModel> {
+    fun getUserInfo(user: String){
         launch {
             mUserInfoModel.value = mUserRepository.getUserInfo(user)
         }
-        return mUserInfoModel
     }
 
     fun getUserPublicRepos(user: String, page: Int): LiveData<List<ReposItemModel>> = emit {