Question

我有一个声明如下的计时器：

var timer: DispatchSourceTimer?

override func viewDidLoad() {
    super.viewDidLoad()

    ...

    timer = DispatchSource.makeTimerSource()
    timer!.scheduleRepeating(deadline: .now() + .seconds(60), interval: .seconds(3600), leeway: .seconds(1))
    timer!.setEventHandler { [weak self] in
        self?.saveData()
    }
    timer!.resume()
    print("TIMER HAS STARTED")
}

此代码在我的viewDidLoad方法中执行，并在我包含的1分钟延迟后第一次正确触发。然后应该每小时开火一次。我在模拟器中运行我的应用程序，使其始终处于关注状态。事实上它仍在运行。

第一次保存数据时我记录了上午11:45的时间。它直到下午1点再次保存，然后在2点08分再次保存。我错过了什么？

编辑：测试这个计时器时，我每分钟都能获得数据，但对于实际的应用程序，我需要每小时进行一次。

Answer 1

就我而言，当DispatchSourceTimer在viewDidLoad内创建实例时，DispatchSourceTimer不会触发事件，不确定原因，多次尝试。

因此，请确保将property作为interval，并且您也可以尝试缩短delay和DispatchSourceTimer // MARK: - Properties var timer: DispatchSourceTimer! // MARK: - Functions // MARK: Overrdes override func viewDidLoad() { super.viewDidLoad() timer = DispatchSource.makeTimerSource() timer.schedule(deadline: .now() + .seconds(1), repeating: .seconds(5), leeway: .seconds(1)) timer.setEventHandler(handler: { [weak self] in guard let strongSelf = self else { return } strongSelf.saveData() }) timer.resume() } func saveData() { print("❇️Invoked...") }参数为了测试而安排的时间表，如下：

public class findLeader {

 static class ArrayStack{
    private int[] stackArr;
    private int tos;//top of stack

    public ArrayStack(){
        stackArr = new int[10];
        tos = -1;
    }

    public ArrayStack(int size){
        stackArr = new int[size];
        tos = -1;
    }

    public ArrayStack(int[] arr, int tos){
        stackArr = arr;
        this.tos = tos;
    }

    public boolean isEmpty(){
       return(tos == -1);
    }

    public int peek(){
        if(isEmpty()){
            return -999;
        }
        return stackArr[tos];
    }

    public void push(int x){
        if(tos == stackArr.length - 1){
            return;
        }
        stackArr[++tos] = x;
    }

    public int pop(){
        if(isEmpty()){
            return -999;
        }
        int popValue = stackArr[tos];
        stackArr[tos] = 0;
        --tos;
        return popValue;
    }

    public void print(){
        if(isEmpty()){
            return;
        }
        for(int i = 0; i <= tos; ++i){
            System.out.print(stackArr[i] + " ");
        }
        System.out.println();
    }

}

public static int leader(ArrayStack myStack){

    int initSize = myStack.tos + 1; //gets initial size of stack.
    int leader; //initialize leader or majority.

    while(!myStack.isEmpty()){
        leader = myStack.peek();//set first leader variable to the element at the tos.
        System.out.println("leader " + leader); //just for debugging
        System.out.println("tos " + myStack.tos); //debugging
        //System.out.println(isLeader(myStack, initSize, leader)); //debugging
        if(isLeader(myStack, initSize, leader)){      
          return 1;  
        }
        else{  
            myStack.pop();
        }
        System.out.println("after function tos " + myStack.tos); //debugging         
    }

    return -1;
}

public static boolean isLeader(ArrayStack myStack, int initSize, int leader){
    ArrayStack as = myStack;
    int count = 0;

    while(!as.isEmpty()){
        if(as.peek() == leader){
            as.pop();
            ++count;
        }
        else{
            as.pop();
        }
    }
    //System.out.println(count);
    if(count > initSize / 2)
        return true;
    else{  
        return false;
    }
}

public static void main(String[] args) {
    int[] arr = {2, 5, 6, 2, 8, 2, 8, 2, 2};

    ArrayStack stack = new ArrayStack();

    stack.push(5);
    stack.push(2);
    stack.push(6);
    stack.push(2);
    stack.push(8);
    stack.push(2);
    stack.push(2);
    stack.push(2);
    stack.push(5);

    System.out.println(leader(stack));

}

Swift Dispatch Source Timer没有按计划发射

1 个答案: