![C时间延迟]( "C时间延迟")
本文介绍了Objective-C时间延迟的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
每当一个函数循环一个循环时，我希望能够执行一个延迟。我已经有一个循环设置，如下所示： for（float batteryPercentage = 1; batteryPercentage {
double timeUntilNextDegreeDrop = 9.0;
dispatch_time_t time = dispatch_time（DISPATCH_TIME_NOW，（int64_t）（timeUntilNextDegreeDrop * NSEC_PER_SEC））;
dispatch_after（time，dispatch_get_main_queue（），^（void）
{
[batteryLevel setProgress：batteryPercentage animated：YES];
float batteryLevelPercentage = batteryPercentage * 100;
batteryLevelLabel.text = [NSString stringWithFormat：@Battery Level：％f %%，batteryLevelPercentage];
}）;
batteryPercentage 是变量，我试图从1到0每9秒递减0.01，直到值达到0.程序的总长度应该是900秒（15分钟）。每9秒钟，我希望此代码每9秒执行一次，并更改名为 batteryLevel 的 UIProgressView 的值。然后，我想将 batteryPercentage 乘以100，得到一个整数百分数，例如乘以0.67得到67，然后替换 batteryLevelLabel 文本与新值。当我尝试执行此操作时， batteryLevel Progress View不会填充，文本也不会更改。我假设定时器有什么问题，那么输入一个9秒延迟的更有效的方法是什么？解决方案
>按照建议尝试使用nstimer
[NSTimer scheduledTimerWithTimeInterval：9.0
target：self
selector：@selector （targetMethod :)
userInfo：nil
repeats：YES];
// targetMethod每9秒调用
//调用
[myTimer invalidate]; myTimer = nil; 任务完成时
I want to be able to execute a delay every time that a function loops through a loop. I already have a loop setup, as shown below:
for (float batteryPercentage = 1; batteryPercentage <= 0; batteryPercentage -= 0.01)
{
double timeUntilNextDegreeDrop = 9.0;
dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(timeUntilNextDegreeDrop * NSEC_PER_SEC));
dispatch_after (time, dispatch_get_main_queue(), ^(void)
{
[batteryLevel setProgress:batteryPercentage animated:YES];
float batteryLevelPercentage = batteryPercentage * 100;
batteryLevelLabel.text = [NSString stringWithFormat:@"Battery Level: %f%%", batteryLevelPercentage];
});
}
batteryPercentage is the variable that I am trying to decrement from 1 to 0 by 0.01 every 9 seconds until the value reaches 0. The total length of the program should be 900 seconds (15 minutes). Every 9 seconds, I want this code to execute every nine seconds and to change the value of the UIProgressView called batteryLevel. Then, I want to multiply batteryPercentage by 100, to get a whole percentage number, such as multiplying 0.67 to get 67, then replace the batteryLevelLabel text with the new value. When I try and execute this, the batteryLevel Progress View simply doesn't fill and the text doesn't change. I'm assuming there's something wrong with the timer, so what would be a more effective way of inputing a 9 second delay?
解决方案
try with nstimer as suggested
[NSTimer scheduledTimerWithTimeInterval:9.0
target:self
selector:@selector(targetMethod:)
userInfo:nil
repeats:YES];
//targetMethod will be called every 9 second//call[myTimer invalidate]; myTimer = nil; when your task is done
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