javascript函数等待另一个函数完成 [英] javascript function wait until another function to finish

问题描述

我有两个从android调用的javascript函数。经过漫长的调试会话，我终于意识到，问题是由于第二个函数在第一个函数完成之前被调用的事实引起的。我已经搜索的例子与deferred等，但他们都依赖于另一个函数调用。

I have two javascript functions that are called from android. After long debug sessions finally I realized that the problem is arising from the fact that second function is getting called before first one is finished. I already searched the examples with deferred etc, but they all depends on function calls within another one.

function FunctInit(someVarible){ //someVariable is sent from android, cannot call again from getResult
//init and fill screen
}

function getResult(){ //also getResult need to be called from android via button
//return some variables
}

如何强制getResult等待FuncInit？有没有办法通过Javascript实现？

How can I force getResult to wait FuncInit? Is there a way to achieve this via Javascript?

推荐答案

在我看来，延迟/承诺

这里是一个 example 我刚刚写了一篇文章来演示如何使用deferred / promise来做到这一点。

Here is an example I have just written to demonstrate how you could do it using deferreds/promises.

花一些时间来处理延迟。一旦你真正了解他们，它就变得非常容易执行异步任务。

Take some time to play around with deferreds. Once you really understand them, it becomes very easy to perform asynchronous tasks.

希望这有助于！

$(function(){
    function1().done(function(){
        // function1 is done, we can now call function2
        console.log('function1 is done!');

        function2().done(function(){
            //function2 is done
            console.log('function2 is done!');
        });
    });
});

function function1(){
    var dfrd1 = $.Deferred();
    var dfrd2= $.Deferred();

    setTimeout(function(){
        // doing async stuff
        console.log('task 1 in function1 is done!');
        dfrd1.resolve();
    }, 1000);

    setTimeout(function(){
        // doing more async stuff
        console.log('task 2 in function1 is done!');
        dfrd2.resolve();
    }, 750);

    return $.when(dfrd1, dfrd2).done(function(){
        console.log('both tasks in function1 are done');
        // Both asyncs tasks are done
    }).promise();
}

function function2(){
    var dfrd1 = $.Deferred();
    setTimeout(function(){
        // doing async stuff
        console.log('task 1 in function2 is done!');
        dfrd1.resolve();
    }, 2000);
    return dfrd1.promise();
}

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