如何使QML中的XMLHttpRequest超时？我有以下代码，但它不会超时。似乎没有实现超时功能！？有其他方法可以实现超时吗？
var http = new XMLHttpRequest();
http.open("POST", "http://localhost/test.xml", true);
http.setRequestHeader('Content-type', 'application/json; charset=utf-8')
http.timeout = 4000;
http.ontimeout = function () {
console.log("timed out")
}
http.onreadystatechange = function() {
if (http.readyState === XMLHttpRequest.DONE) {
// Do something
}
}
http.send(JSON.stringify(data));
编辑：代码不在qml中，而是在js文件中。它不会进入qml文件，因为它是模型（MVC）的一部分。
看起来QML XMLHttpRequest不支持timeout功能。这是支持的功能/属性子集列表：
http://qt-project.org/doc/qt-5/qtqml-javascript-qmlglobalobject.html#xmlhttprequest
但是您可以使用QML Timer项来实现此目的，例如：
import QtQuick 2.3
Item {
id: root
width: 600
height: 400
Text {
anchors.fill: parent
id: response
text: "Click me"
horizontalAlignment: Text.AlignHCenter
verticalAlignment: Text.AlignVCenter
MouseArea {
anchors.fill: parent
onClicked: {
response.text = "Loading...";
var req = new XMLHttpRequest();
var timer = Qt.createQmlObject("import QtQuick 2.3; Timer {interval: 4000; repeat: false; running: true;}",root,"MyTimer");
timer.triggered.connect(function(){
req.abort();
response.text = "timed out";
});
req.open("GET","http://google.com--",true); // correct me
req.onreadystatechange = function() {
if (req.readyState === XMLHttpRequest.DONE && req.status == 200) {
response.text = req.getAllResponseHeaders();
timer.running = false;
}
}
req.send();
}
}
}
}
一个全局的setTimeout（）和setInterval（）用程序，用于对浏览器中的功能进行建模。
它可以用于间接地使XMLHttpRequest超时。或者在应用程序的其他地方谨慎使用。
timeoutId = util.timer.setTimeout(function() {}, 4500);
util.timer.clearInterval(timeoutId);
主QML代码段
使用以下代码，任何子级都可以访问app.util.timer命名空间下的方法（如果JS代码加载在主codeehind文件中，则访问util.timer[/em>命名空间）。
import "CodeBehind.js" as CodeBehind
id: appWindow
QtObject {
id: app
property var util: CodeBehind.util
}
Component.onCompleted: {
CodeBehind.util.timer.init(appWindow);
}
CodeBehindJS代码段
var util = util || {};
Qt.include("qrc:/Util/Timer.js");
实用程序JS文件
var util = util || {};
/**
Mimics the window.setTimeout() and window.setInterval() functionality
found in browsers.
@namespace timer
@memberof util
*/
util.timer = new function() {
var _timer;
var _timerList = [];
var _currentTime = 0;
var _api = {};
var _private = {};
var _enums = {};
/*************** Private ENUMS ***************/
_enums.type = {
timeout: 0,
interval: 1
};
/*************** Public API Methods ***************/
/**
Mimics the window.setTimeout() functionality found in browsers.
@param {function} callback
@param {int} interval Milliseconds
@public
@memberof util.timer
*/
_api.setTimeout = function(callback, interval) {
var timer, id;
id = parseInt(Math.random() * Date.now());
timer = new Timer(id, callback, interval, _enums.type.timeout);
_timerList.push({ id: id, timer: timer });
return id;
};
/**
Mimics the window.setInterval() functionality found in browsers.
@param {function} callback
@param {int} interval Milliseconds
@public
@memberof util.timer
*/
_api.setInterval = function(callback, interval) {
var timer, id;
id = parseInt(Math.random() * Date.now());
timer = new Timer(id, callback, interval, _enums.type.interval);
_timerList.push({ id: id, timer: timer });
return id;
};
/**
Clears an interval or timout by the interval id that is returned
when setTimeout() or setInterval() is called.
@param {int} intervalId
@public
@memberof util.timer
*/
_api.clearInterval = function(intervalId) {
var idx, len, idxOfTimer;
if (_timerList) {
// Find the index of the timer
len = _timerList.length;
for (idx = 0; idx < len; idx++) {
if (_timerList[idx].id === intervalId) {
idxOfTimer = idx;
break;
}
}
// Remove the timer from the array
_timerList.splice(idxOfTimer, 1);
}
// If: There are no more timers in the timer list
// Then: Stop the QML timer element
if (!_timerList || _timerList.length === 0) {
_private.stop();
}
};
/*************** Private Helper Methods ***************/
_private.start = function() {
_timer.start();
};
_private.stop = function() {
_timer.stop();
_currentTime = 0;
};
_private.runInterval = function() {
var idx, len, tempList;
// Increment the current timer
_currentTime++;
if (_timerList) {
// Create a temp list of timers
tempList = [];
len = _timerList.length;
for (idx = 0; idx < len; idx++) {
tempList.push(_timerList[idx].timer);
}
// Trigger each method
len = tempList.length;
for (idx = 0; idx < len; idx++) {
tempList[idx].trigger();
}
}
};
/*************** Objects ***************/
/**
A timer object contains a trigger to check and see if it needs
to run the callback.
@param {int} id
@param {function} callback
@param {int} interval Milliseconds
@param {enum} type type.interval | type.timeout
@public
@memberof util.timer
*/
var Timer = function(id, callback, interval, type) {
var _obj = {};
_obj.api = {};
_obj.hasRun = false;
_obj.endTime = _currentTime + interval;
_obj.api.trigger = function() {
if (_currentTime >= _obj.endTime && !_api.hasRun) {
_obj.hasRun = true;
callback();
if (type === _enums.type.interval) {
_obj.endTime += interval;
_api.hasRun = false;
}
else {
_api.clearInterval(id);
}
}
};
_private.start();
return _obj.api;
};
/*************** Initialize ***************/
_api.init = function(appWindow) {
_timer = Qt.createQmlObject("import QtQuick 2.3; Timer { interval: 1; repeat: true; running: false;}", appWindow, "timer");
_timer.triggered.connect(_private.runInterval);
};
return _api;
};