如何解决Kotlin MutableStateFlow.collect正在删除值
我有一个Android应用程序,其中我试图使用协程流使用自己的event bus library来替换现有的Otto EventBus。设置MutableStateFlow的值,然后收集我的应用程序的代码时,我看到丢弃的值。我创建了一个更简单的项目来演示相同的问题。关于为何从MutableStateFlow中删除值的任何想法?
项目的build.gradle
buildscript {
ext.kotlin_version = "1.4.10"
repositories {
google()
jcenter()
}
dependencies {
classpath "com.android.tools.build:gradle:4.0.1"
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath 'com.google.gms:google-services:4.3.3'
classpath 'com.google.firebase:firebase-crashlytics-gradle:2.3.0'
classpath 'com.google.firebase:perf-plugin:1.3.1'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
google()
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
应用程序模块的build.gradle
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.google.gms.google-services'
apply plugin: 'com.google.firebase.crashlytics'
apply plugin: 'com.google.firebase.firebase-perf'
android {
compileSdkVersion 29
buildToolsVersion "29.0.3"
defaultConfig {
applicationId "com.cren90.sandbox"
minSdkVersion 23
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'),'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: "libs",include: ["*.jar"])
implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
implementation 'androidx.core:core-ktx:1.3.1'
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.7'
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.fragment:fragment:1.2.5'
implementation 'androidx.fragment:fragment-ktx:1.2.5'
implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.2.0'
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.2.0'
implementation 'androidx.lifecycle:lifecycle-viewmodel:2.2.0'
implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
implementation 'com.google.firebase:firebase-analytics:17.5.0'
implementation 'com.google.firebase:firebase-crashlytics:17.2.1'
implementation 'com.google.firebase:firebase-perf:19.0.8'
implementation 'com.google.firebase:firebase-messaging:20.2.4'
implementation 'com.jakewharton.timber:timber:4.7.1'
implementation 'androidx.legacy:legacy-support-v4:1.0.0'
implementation 'androidx.navigation:navigation-runtime:2.3.0'
implementation 'androidx.navigation:navigation-fragment:2.3.0'
implementation 'androidx.navigation:navigation-ui:2.3.0'
implementation 'androidx.navigation:navigation-runtime-ktx:2.3.0'
implementation 'androidx.navigation:navigation-fragment-ktx:2.3.0'
implementation 'androidx.navigation:navigation-ui-ktx:2.3.0'
testImplementation 'junit:junit:4.13'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}
MainActivity.kt
package com.cren90.sandbox
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.navigation.findNavController
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.launch
import timber.log.Timber
import java.lang.RuntimeException
class MainActivity : AppCompatActivity() {
val flow: MutableStateFlow<Int> = MutableStateFlow<Int>(0)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
CoroutineScope(Dispatchers.IO).launch {
flow.collect {
Timber.d("cren90 - $it")
}
}
}
override fun onStart() {
super.onStart()
(application as SandboxApplication).apply {
startupTrace.putAttribute("APP_UUID",uuid)
startupTrace.stop()
}
}
override fun onResume() {
super.onResume()
for(i in 0..100) {
flow.value = i
}
}
}
我希望它能记录下来
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 0
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 1
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 2
...
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 98
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 99
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 100
但它会记录
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 0
//Maybe 1 or 2 other random values in the 0-100 range
2020-09-30 18:10:02.826 10533-10611/com.cren90.sandbox D/MainActivity$onCreate$1$invokeSuspend$$inlined$collect: cren90 - 100
解决方法
StateFlow官方文档指出:
可变状态流的值可以通过设置其值来更新 属性。值的更新总是混合在一起。这么慢 收集器跳过快速更新,但总是收集最新的 发射值。
您可以找到StateFlow官方文档here。
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。