Android 如何正确地等待HandlerThread启动,然后再进行操作?
在我的项目中,有时创建的线程启动速度不如它应该的快,这种情况很少发生,但大多数情况下会发生在速度较慢/较旧的手机上 我喜欢我的线Android 如何正确地等待HandlerThread启动,然后再进行操作?,android,android-handlerthread,Android,Android Handlerthread,在我的项目中,有时创建的线程启动速度不如它应该的快,这种情况很少发生,但大多数情况下会发生在速度较慢/较旧的手机上 我喜欢我的线 class DBThread(threadName: String) : HandlerThread(threadName) { private var mWorkerHandler: Handler? = null override fun onLooperPrepared() { super.onLooperPrepared()
class DBThread(threadName: String) : HandlerThread(threadName) {
private var mWorkerHandler: Handler? = null
override fun onLooperPrepared() {
super.onLooperPrepared()
mWorkerHandler = Handler(looper)
}
fun createTask(task: Runnable) {
mWorkerHandler?.post(task)
}
}
当我使用它并调用活动时
//this will handle db queries on background and not on main ui thread
var mDbThread: DBThread = DBThread("dbThread")
//use this to interact to main ui thread from different thread
val mUiHandler = Handler()
var mDb: LocalDatabase? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mDbThread.start()
mDb = LocalDatabase.getInstance(this)
fetchAndSetList()
}
override fun onDestroy() {
super.onDestroy()
LocalDatabase.destroyInstance()
mDbThread.quitSafely()
}
private fun fetchAndSetList(){
mDbThread.createTask(Runnable {
val list = getList()
mUiHandler.post {
// this sometimes does not trigger
setList(list)
}
})
}
函数setList有时不会在上触发。
所以我做了类似的事情
fun createTask(task: Runnable) {
if(mWorkerHandler == null ){
createTask(task)
return
}
mWorkerHandler?.post(task)
}
修改后的操作似乎有效,但我不确定这是否是一种安全的方法。提前谢谢。我认为mWorkerhandler为null的原因是Thread.start将创建新的VMThread并在VMThread中启动循环器。整个流程都是异步的,因此当实际调用onLooperPrepared时,为时已晚,因为“fetchAndSetList”已经在尝试使用mWorkerHandler 解决方案是在HandlerThread之外创建处理程序:
Handler workerHandler;
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
mDbThread.start()
workerHandler = new Handler(mDbThread.getLooper());
mDb = LocalDatabase.getInstance(this)
fetchAndSetList()
}
private fun fetchAndSetList(){
workerHandler.post(Runnable {
val list = getList()
mUiHandler.post {
// this sometimes does not trigger
setList(list)
}
})
}
嘿,真的很抱歉很晚才回复,使用你在链接和Zulitim上的答案,我终于理解了流程,是的,在主线程上获得活套是正确的。非常感谢你