当用户移动地图而不是setCenter方法时捕获bounds_changed事件 [英] Catch bounds_changed event when user moves the map but not the setCenter method

问题描述

我想在用户移动地图时，监听bounds_changed事件，更改缩放但我不想在我的程序调用setCenter或setZoom方法时触发它。所以我在设置中心之前尝试删除事件，然后再次添加它。然而，它没有奏效，我的事件仍然被解雇。

I want to listen 'bounds_changed' event when the user moves the map, changes the zoom but I don't want it to be fired when my program calls setCenter or setZoom methods. So I tried removing event before setting center and adding it after, again. However, it didn't worked, My event is still being fired.

var currentBoundsListener = null;

function addBoundsChangedListener() {
    currentBoundsListener = google.maps.event.addListener(map, 'bounds_changed', function () {
        // Whatever.
    });
}

function setCenter(lat, lng) {
    google.maps.event.removeListener(currentBoundsListener);
    var geo = new google.maps.LatLng(lat, lng);
    map.setCenter(geo);
    addBoundsChangedListener();
}

我认为地图正在创建bounds_changed事件后，我添加了新的侦听器，就像事件是异步的。

I think the map is creating bounds_changed event after I add the new listener to it, like the event is asynchronised.

推荐答案

bounds_changed事件确实是异步触发的，所以不是删除侦听器，而是使用指示何时忽略它的全局布尔变量，例如：

The bounds_changed event is indeed fired asynchronously so, instead of removing the listener you could use a global boolean variable that indicates when to ignore it, for example:

var ignore = false; // this var is global;
currentBoundsListener = google.maps.event.addListener(map, 'bounds_changed', function () {
if(ignore) {
   ignore = false;
   return;
}

// Whatever.
});


function setCenter(lat, lng) {
    var geo = new google.maps.LatLng(lat, lng);
    ignore = true;
    map.setCenter(geo);
}

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