timer

问题 I'm writing an app in Swift where a timer counts down, much like a countdown clock. To do this I am using this code in my main logics class: func start() { self.timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { timer in self.run() } } Now every time I close the app, the timer stops and I get this error: BackgroundTask: no background task exists with identifier 1 (0x1), or it may have already been ended. Is there any way to continue the timer running in the background? Or do

问题 I'm writing an app in Swift where a timer counts down, much like a countdown clock. To do this I am using this code in my main logics class: func start() { self.timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { timer in self.run() } } Now every time I close the app, the timer stops and I get this error: BackgroundTask: no background task exists with identifier 1 (0x1), or it may have already been ended. Is there any way to continue the timer running in the background? Or do

问题 Apologies in advance for any tacky code (I'm still learning Swift and SwiftUI). I have a project where I'd like to have multiple timers in an Array count down to zero, one at a time. When the user clicks start, the first timer in the Array counts down and finishes, and a completion handler is called which shifts the array to the left with removeFirst() and starts the next timer (now the first timer in the list) and does this until all timers are done. I also have a custom Shape called

问题 Apologies in advance for any tacky code (I'm still learning Swift and SwiftUI). I have a project where I'd like to have multiple timers in an Array count down to zero, one at a time. When the user clicks start, the first timer in the Array counts down and finishes, and a completion handler is called which shifts the array to the left with removeFirst() and starts the next timer (now the first timer in the list) and does this until all timers are done. I also have a custom Shape called

问题 Taking the same idea of this post: R shiny: display "loading..." message while function is running I'd like actually not only display a "loading" message, but also display the elapsed time of the run. And at the end, that the final running time remains displayed. I adapt a MWE from the R-bloggers https://www.r-bloggers.com/long-running-tasks-with-shiny-challenges-and-solutions/ library(shiny) ui <- fluidPage( # Sidebar with a slider input for number of bins sidebarLayout( sidebarPanel(

问题 I have a realtime signal from a sensor. I need logic to implement a masking time once the signal is above a threshold. As shown below: Here the signal (in blue) crosses a threshold. And I need to mask for any checks for the threshold for a period (masking time). (In this way I can detect only the positive pulse , similarly, I have another check for negative pulse ) See the code below: static QTime time(QTime::currentTime()); // calculate two new data points: double key = time.elapsed()/1000.0

问题 I have a realtime signal from a sensor. I need logic to implement a masking time once the signal is above a threshold. As shown below: Here the signal (in blue) crosses a threshold. And I need to mask for any checks for the threshold for a period (masking time). (In this way I can detect only the positive pulse , similarly, I have another check for negative pulse ) See the code below: static QTime time(QTime::currentTime()); // calculate two new data points: double key = time.elapsed()/1000.0

问题 How to add wait of 30 sec. in between 2 loop controller? Each loop controller has loop count 10. Scenario: 1.No. of threads=5 2.For each user, No. of loop controllers=5 Loop_controller_1(count=10, i.e. 10 HTTP request) Wait for 10 sec Loop_controller_2(count=10 i.e. 10 HTTP request) wait for 10 sec Loop_controller_3(count=10 i.e. 10 HTTP request) wait for 10 sec Loop_controller_4(count=10 i.e. 10 HTTP request) wait for 10 sec Loop_controller_5(count=10 i.e. 10 HTTP request) wait for 10 sec

问题 I'm curious about the delay time between the title mentioned, I toggled an IO when I wrote data into UART->DR, the delay time varies from 3 micro seconds to 10x micro seconds int main(void) { /* initial code generated by STMCubeMX */ HAL_Init(); SystemClock_Config(); MX_GPIO_Init(); MX_USART1_UART_Init(); while (1) { HAL_Delay(50); if (USART_GetFlagStatus(&huart1, USART_SR_TXE) == SET) { USART_SendData(&huart1, 'F'); } } } void USART_SendData(UART_HandleTypeDef *huart, uint16_t Data) { assert

问题 i have a timer in SwiftUI which works when opening the view for the first time. When navigating back and opening again, the timer does not start. Any idea what can be wrong ? import SwiftUI struct ClockDetail: View { @State var seconds: Int = 0 @ObservedObject var motion: MotionManager let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect() var body: some View { VStack(alignment: .leading) { Text("\(seconds)").font(.title).onReceive(timer) { output in self.seconds += 1 }