我关注 this official guide on coroutine ，并且 StrickMode 一直提示磁盘读/写是在 MainThread 上完成的(isSignedIn 使用 SharedPreference)，即使我已经指定它在 Dispatchers.IO 上运行。 .
override fun onStart() {
super.onStart()
launch {
val isSignedIn = async(Dispatchers.IO) { viewModel.isSignedIn() }
val navigationAction = if (isSignedIn.await()) R.id.action_splashFragment_to_mainFragment
else R.id.action_splashFragment_to_whatIsLoftFragment
withContext(Dispatchers.Main) { navigateToNextWithDelay(action = navigationAction) }
}
}
viewModel.isSignedIn()不在后台线程上运行？ 更新:添加 StrictMode 配置和日志
private fun setupStrictMode() {
if (BuildConfig.DEBUG) {
StrictMode.setThreadPolicy(StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.penaltyDeath()
.build()
)
StrictMode.setVmPolicy(StrictMode.VmPolicy.Builder()
.detectAll()
.penaltyLog()
.penaltyDeath()
.build()
)
}
}
日志:
2018-10-14 13:11:36.411 13542-13542/io.github.louistsaitszho.loft E/AndroidRuntime: FATAL EXCEPTION: main
Process: io.github.louistsaitszho.loft, PID: 13542
java.lang.RuntimeException: StrictMode ThreadPolicy violation
at android.os.StrictMode$AndroidBlockGuardPolicy.onThreadPolicyViolation(StrictMode.java:1705)
at android.os.StrictMode$AndroidBlockGuardPolicy.lambda$handleViolationWithTimingAttempt$0(StrictMode.java:1619)
at android.os.-$$Lambda$StrictMode$AndroidBlockGuardPolicy$9nBulCQKaMajrWr41SB7f7YRT1I.run(Unknown Source:6)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: android.os.strictmode.DiskReadViolation
at android.os.StrictMode$AndroidBlockGuardPolicy.onReadFromDisk(StrictMode.java:1504)
at java.io.UnixFileSystem.getBooleanAttributes(UnixFileSystem.java:241)
at java.io.File.isDirectory(File.java:845)
at dalvik.system.DexPathList$Element.maybeInit(DexPathList.java:696)
at dalvik.system.DexPathList$Element.findResource(DexPathList.java:729)
at dalvik.system.DexPathList.findResources(DexPathList.java:526)
at dalvik.system.BaseDexClassLoader.findResources(BaseDexClassLoader.java:174)
at java.lang.ClassLoader.getResources(ClassLoader.java:839)
at java.util.ServiceLoader$LazyIterator.hasNextService(ServiceLoader.java:349)
at java.util.ServiceLoader$LazyIterator.hasNext(ServiceLoader.java:402)
at java.util.ServiceLoader$1.hasNext(ServiceLoader.java:488)
at kotlin.collections.CollectionsKt___CollectionsKt.toCollection(_Collections.kt:1062)
at kotlin.collections.CollectionsKt___CollectionsKt.toMutableList(_Collections.kt:1095)
at kotlin.collections.CollectionsKt___CollectionsKt.toList(_Collections.kt:1086)
at kotlinx.coroutines.experimental.MainDispatcherLoader.<clinit>(Dispatchers.kt:97)
at kotlinx.coroutines.experimental.Dispatchers.getMain(Dispatchers.kt:54)
at io.github.louistsaitszho.loft.ScopedFragment.getCoroutineContext(ScopedFragment.kt:20)
at kotlinx.coroutines.experimental.CoroutineContextKt.newCoroutineContext(CoroutineContext.kt:81)
at kotlinx.coroutines.experimental.BuildersKt__Builders_commonKt.launch(Builders.common.kt:49)
at kotlinx.coroutines.experimental.BuildersKt.launch(Unknown Source:1)
at kotlinx.coroutines.experimental.BuildersKt__Builders_commonKt.launch$default(Builders.common.kt:46)
at kotlinx.coroutines.experimental.BuildersKt.launch$default(Unknown Source:1)
at io.github.louistsaitszho.loft.splash.SplashFragment.onStart(SplashFragment.kt:28)
at android.support.v4.app.Fragment.performStart(Fragment.java:2372)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1467)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1759)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1827)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3244)
at android.support.v4.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:3206)
at android.support.v4.app.Fragment.performStart(Fragment.java:2378)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1467)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1759)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1827)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3244)
at android.support.v4.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:3206)
at android.support.v4.app.FragmentController.dispatchStart(FragmentController.java:206)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:605)
2018-10-14 13:11:36.412 13542-13542/io.github.louistsaitszho.loft E/AndroidRuntime: at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:177)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1391)
at android.app.Activity.performStart(Activity.java:7157)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:2937)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:180)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:165)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:142)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
最佳答案
我认为您遇到了 Slow android Dispatchers.Main init 中报告的问题.
这在堆栈跟踪的以下部分中可见:
at dalvik.system.BaseDexClassLoader.findResources(BaseDexClassLoader.java:174)
at java.lang.ClassLoader.getResources(ClassLoader.java:839)
at java.util.ServiceLoader$LazyIterator.hasNextService(ServiceLoader.java:349)
at java.util.ServiceLoader$LazyIterator.hasNext(ServiceLoader.java:402)
at java.util.ServiceLoader$1.hasNext(ServiceLoader.java:488)
它已在版本 1.3.3 which landed in December 中修复:
Avoid ServiceLoader for loading Dispatchers.Main (#1572, #1557, #878, #1606).
关于android - StrictMode.detectNetwork/Disk 是否仍然适用于协程世界？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52801890/