Question

在Flash Canvas HTML5的javascript（createJS）中进行简单的倒计时，我收到以下错误：file_Canvas.js:318 Uncaught TypeError: Cannot read property 'dtxt_days' of undefined。（该错误特定于行this.mc_counter.dtxt_days.text = days;和下面的3。

我做错了什么？

这是js：

this.mc_counter.dtxt_days.text = "";
this.mc_counter.dtxt_hours.text = "";
this.mc_counter.dtxt_mins.text = "";
this.mc_counter.dtxt_secs.text = "";

var end = new Date('10/19/2015 10:1 AM');

var _second = 1000;
var _minute = _second * 60;
var _hour = _minute * 60;
var _day = _hour * 24;
var timer;

function showRemaining() {
    var now = new Date();
    var distance = end - now;

    this.days = Math.floor(distance / _day);
    this.hours = Math.floor((distance % _day) / _hour);
    this.minutes = Math.floor((distance % _hour) / _minute);
    this.seconds = Math.floor((distance % _minute) / _second);

    this.mc_counter.dtxt_days.text = days;
    this.mc_counter.dtxt_hours.text = hours;
    this.mc_counter.dtxt_mins.text = minutes;
    this.mc_counter.dtxt_secs.text = seconds;
}


timer = setInterval(showRemaining, 1000);

console.log(timer);

Answer 1

您将具有错误的代码行中的变量分配给不存在的内容。

@LargeTest
public class SmokeSetup extends LogInTestFixture {

    @Rule
    public ActivityTestRule<LoginActivity> mLoginActivity = new ActivityTestRule<>(LoginActivity.class);

    @Test
    public void testSetup() throws IOException {

        onView(withId(R.id.username_field)).perform(replaceText("username"));
        onView(withId(R.id.password_field)).perform(replaceText("password"));
        onView(withId(R.id.login_button)).perform(click());

    }

}

@LargeTest
public class LogoutTearDown extends LogInTestFixture {

    @Rule
    public ActivityTestRule<MainActivity> mMainActivity = new ActivityTestRule<>(MainActivity.class);

    @Test
    public void testLogout() throws IOException {

        onView(withId(R.id.toolbar_menu)).perform(click());
        onView(withId(R.id.logout_button)).perform(click());

    }

}

相反，请确保您获得刚刚分配给this.days != days的属性。

this

此外 - this.mc_counter.dtxt_days.text = this.days; this.mc_counter.dtxt_hours.text = this.hours; this.mc_counter.dtxt_mins.text = this.minutes; this.mc_counter.dtxt_secs.text = this.seconds;并未指出您的想法。由于this是一个函数，因此其中的代码中的showRemaining实际上是指this。有几种方法可以解决这个问题。这可以说是最简单的一个：

showRemaining

这只是存储对外var self = this; function showRemaining() { self.days = ... self.mc_counter.dtxt_days.txt = ... }的引用。或者，您可以执行以下操作：

this

将timer = setInterval(showRemaining.call(this), 1000);内this分配给外showRemaining。

Javascript for Flash Canvas HTML5中的倒计时时钟计时器

1 个答案: