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  5. WebEngine Qt Quick 自定义对话框范例

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WebEngine Qt Quick 自定义对话框范例

A web page might request dialogs for various purposes, such as authentication, picking colors, choosing files, and responding to JavaScript alerts, confirmation requests, and prompts.

自定义对话框 demonstrates how to use WebEngine dialog request objects to implement custom dialogs for use instead of the default dialogs.

运行范例

要运行范例从 Qt Creator ，打开 欢迎 模式，然后选择范例从 范例 。更多信息，拜访 构建和运行范例 .

WebEngineView UI 元素

In this example, we create a simple index.html page that contains buttons and text fields for triggering a context menu and the following dialogs:

  • HTTP Authentication Dialog
  • Proxy Authentication Dialog
  • JavaScript Alert, Confirm, and Prompt Dialogs
  • Color Picker Dialog
  • File Picker Dialog
  • Form Validation Message

触发对话框

As mentioned, the index.html file is responsible for triggering the dialogs from the side of HTML and JavaScript. Additionally, the example program starts a localhost TCP server returning the mocked HTTP responses needed to trigger proxy and HTTP authentication dialogs.

自定义对话框

The custom dialogs are just Qt Quick Designer UI Forms without any business logic. The point here is to present the glue code that is required to display the custom dialog for a particular web engine dialog or a menu request.

创建主窗口

在 main.cpp , we initialize the WebEngine the same way as in the WebEngine Qt Quick 最小范例 : 

int main(int argc, char *argv[])
{
    Application app(argc, argv);
    QtWebEngine::initialize();
    QQmlApplicationEngine engine;
    Server *server = new Server(&engine);
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));
    QTimer::singleShot(0, server, &Server::run);
    QNetworkProxy proxy;
    proxy.setType(QNetworkProxy::HttpProxy);
    proxy.setHostName("localhost");
    proxy.setPort(5555);
    QNetworkProxy::setApplicationProxy(proxy);
    return app.exec();
}

In addition, we set up a proxy and a TCP server to be able to simulate proxy and HTTP authetication requests.

在 main.qml , we create a top level window, which contains a StackView with a SwitchButton and a WebView : 

import QtQuick.Window 2.0
Window {
    width: 350
    height: 550
    visible: true
    Controls.StackView {
        id: stackView
        anchors.fill: parent
        focus: true
        initialItem: Item {
            id: main
            width: parent.width
            height: parent.height
            ColumnLayout {
                anchors.fill: parent
                SwitchButton {
                    id: switcher
                    Layout.fillWidth: true
                }
                WebView {
                    id: webView
                    useDefaultDialogs: switcher.checked
                    Layout.fillWidth: true
                    Layout.fillHeight: true
                }
            }
        }
        function closeForm()
        {
            pop(main);
        }
        function openForm(form)
        {
            push(form);
            currentItem.closeForm.connect(closeForm);
        }
    }
    Component.onCompleted: {
        webView.openForm.connect(stackView.openForm);
    }
}

处理 Web 引擎请求

In this example, we implement the handling of the following web engine requests:

上下文菜单请求

ContextMenuRequest is a request object that is passed as a parameter of the WebEngineView::contextMenuRequested signal. We use the onContextMenuRequested signal handler to handle requests for #openMenu URL links: 

WebEngineView {
    ...
    onContextMenuRequested: function(request) {
        // we only show menu for links with #openMenu
        if (!request.linkUrl.toString().endsWith("#openMenu")) {
            request.accepted = true;
            return;
        }
        // return early to show default menu
        if (useDefaultDialogs)
            return;
        request.accepted = true;
        openForm({item: Qt.resolvedUrl("forms/Menu.qml"),
                     properties: {"request": request}});
    }
    ...
}

The first text field from the top on our page triggers the request. Next, we check whether we should use the default menu. If not, we accept the request and switch the view to show the MenuForm : 

MenuForm {
    property QtObject request
    signal closeForm()
    followLink.onClicked: closeForm()
    back.onClicked: closeForm()
    forward.onClicked: closeForm()
    reload.onClicked: closeForm()
    copyLinkUrl.onClicked: closeForm()
    saveLink.onClicked: closeForm()
    close.onClicked: closeForm()
    Component.onCompleted: {
        back.btnEnable = false;
        forward.btnEnable = false;
    }
}

To keep things simple, we do not provide any logic on component completion, and we simply close the form on any action.

身份验证对话框请求

AuthenticationDialogRequest is a request object that is passed as a parameter of the WebEngineView::authenticationDialogRequested signal: 

WebEngineView {
    ...
    onAuthenticationDialogRequested: function(request) {
        if (useDefaultDialogs)
            return;
        request.accepted = true;
        openForm({item: Qt.resolvedUrl("forms/Authentication.qml"),
                     properties: {"request": request}});
    }
    ...
}

使用 onAuthenticationDialogRequested signal handler to check whether we should use the default authentication dialog. If not, we accept the request and switch the view to show the AuthenticationForm : 

AuthenticationForm {
    property QtObject request
    signal closeForm()
    cancelButton.onClicked: {
        request.dialogReject();
        closeForm();
    }
    loginButton.onClicked: {
        request.dialogReject();
        closeForm();
    }
    Component.onCompleted: {
        switch (request.type) {
        case  AuthenticationDialogRequest.AuthenticationTypeHTTP:
            console.log("HTTP Authentication Required. Host says: " + request.realm);
            break;
        case  AuthenticationDialogRequest.AuthenticationTypeProxy:
            console.log("Proxy Authentication Required for: " + request.proxyHost);
            break;
        }
    }
}

On component completion, we log the request type. The user can fill in the credentials and click Login . We provide onClicked handlers to accept or reject the authentication dialog. The TCP server on localhost does not handle real authentication, and therefore we call rejectDialog() 而不是 acceptDialog() also for the login button clicked 信号。

JavaScript 对话框请求

JavaScriptDialogRequest is a request object that is passed as a parameter of the WebEngineView::javaScriptDialogRequested signal: 

WebEngineView {
    ...
    onJavaScriptDialogRequested: function(request) {
        if (useDefaultDialogs)
            return;
        request.accepted = true;
        openForm({item: Qt.resolvedUrl("forms/JavaScript.qml"),
                     properties: {"request": request}});
    }
    ...
}

使用 onJavaScriptDialogRequested signal handler to check whether we should use the default JavaScript dialog. If not, we accept the request and switch the view to show the JavaScriptForm : 

JavaScriptForm {
    property QtObject request
    signal closeForm()
    cancelButton.onClicked: {
        request.dialogReject();
        closeForm();
    }
    okButton.onClicked: {
        request.dialogAccept(prompt.text);
        closeForm();
    }
    Component.onCompleted: {
        switch (request.type) {
        case JavaScriptDialogRequest.DialogTypeAlert:
            cancelButton.visible = false;
            title = qsTr("Alert");
            message = request.message;
            prompt.text = "";
            prompt.visible = false;
            break;
        case JavaScriptDialogRequest.DialogTypeConfirm:
            title = qsTr("Confirm");
            message = request.message;
            prompt.text = "";
            prompt.visible = false;
            break;
        case JavaScriptDialogRequest.DialogTypePrompt:
            title = qsTr("Prompt");
            message = request.message;
            prompt.text = request.defaultText;
            prompt.visible = true;
            break;
        }
    }
}

On component completion, we customize the form based on the request type. For a JavaScript prompt dialog we use dialogAccept() 采用 prompt.text 自变量。

颜色对话框请求

ColorDialogRequest is a request object that is passed as a parameter of the WebEngineView::colorDialogRequested signal: 

WebEngineView {
    ...
    onColorDialogRequested: function(request) {
        if (useDefaultDialogs)
            return;
        request.accepted = true;
        openForm({item: Qt.resolvedUrl("forms/ColorPicker.qml"),
                     properties: {"request": request}});
    }
    ...
}

使用 onColorDialogRequested signal handler to check whether we should use the default color picker dialog. If not, we accept the request and switch the view to show the ColorPickerForm : 

ColorPickerForm {
    property QtObject request
    signal closeForm()
    okButton.onClicked: {
        request.dialogAccept(colorPicker.color);
        closeForm();
    }
    cancelButton.onClicked: {
        request.dialogReject();
        closeForm();
    }
    function createCallback(color) {
        return function() { colorPicker.color = color };
    }
    Component.onCompleted:{
        for (var i = 0; i < grid.children.length; i++) {
            var cell = grid.children[i];
            cell.clicked.connect(createCallback(cell.color));
        }
        colorPicker.color = request.color;
    }
}

On component completion, we create callbacks for all the color cells. When the user selects the color and clicks OK , we pass the selected color to the dialogAccept() 方法。

文件对话框请求

FileDialogRequest is a request object that is passed as a parameter of the WebEngineView::fileDialogRequested signal: 

WebEngineView {
    ...
    onFileDialogRequested: function(request) {
        if (useDefaultDialogs)
            return;
        request.accepted = true;
        openForm({item: Qt.resolvedUrl("forms/FilePicker.qml"),
                     properties: {"request": request}});
    }
    ...
}

使用 onFileDialogRequested signal handler to check whether we should use the default color picker dialog. If not, we accept the request and switch the view to show the FilePickerForm : 

FilePickerForm {
    property QtObject request
    property string selectedFile
    signal closeForm()
    cancelButton.onClicked: {
        request.dialogReject();
        closeForm();
    }
    okButton.onClicked: {
        request.dialogAccept('/' + selectedFile);
        closeForm();
    }
    function createCallback(fileIndex) {
        return function() {
            for (var i = 0; i < files.children.length; i++) {
                var file = files.children[i];
                if (i === fileIndex) {
                    selectedFile = file.text;
                    file.selected = true;
                } else {
                    file.selected = false;
                }
            }
        }
    }
    Component.onCompleted: {
        selectedFile = request.defaultFileName;
        for (var i = 0; i < files.children.length; i++) {
            var file = files.children[i];
            file.clicked.connect(createCallback(i));
            if (file.text === selectedFile)
                file.selected = true;
        }
    }

On component completion, we create callbacks for selecting files. When the user selects a file and clicks OK , we pass the selected file to the dialogAccept 方法。

Form Validation Message Requests

FormValidationMessageRequest is a request object that is passed as a parameter of the WebEngineView::formValidationMessageRequested signal: 

WebEngineView {
    url: "qrc:/index.html"
    ...
    onFormValidationMessageRequested: function(request) {
        switch (request.type) {
        case FormValidationMessageRequest.Show:
            if (useDefaultDialogs)
                return;
            request.accepted = true;
            validationMessage.text = request.text;
            validationMessage.y = request.anchor.y + request.anchor.height + 10;
            validationMessage.visible = true;
            break;
        case FormValidationMessageRequest.Move:
            break;
        case FormValidationMessageRequest.Hide:
            validationMessage.visible = false;
            break;
        }
    }
    MessageRectangle {
        id: validationMessage
        z: 1
    }
}

使用 onFormValidationMessageRequested signal handler to check whether we should use the default message bubble. If not, we accept the request and customize validationMessage . Depending on the type of the request, we show, move, or hide the message.

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