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SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

SAPUI5 View Controller lifecycle methods

Create an Application Project for SAPUI5

打开 Eclipse 并转到菜单选项,文件 -> 新建 -> 其他…。 在 New 窗口中,打开节点 SAPUI5 Application Development 并选择 Application Project 选项。 单击下一步按钮。

SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods
为项目提供一个名称。 我们称之为 UI5LifecycleDemo。 选择库 sap.ui.commons 并选中 Create an Initial View 选项。 单击下一步按钮。
SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods
在下一个窗口中,为视图提供一个名称。 我们称其为主要的。 选择开发范式作为 JavaScript。 这将在 JavaScript 中创建一个视图。 单击完成按钮。
SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods
创建好的 SAP UI5 项目层级结构如下:
SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

Write View Logic

main.view.js 的内容:

sap.ui.jsview("ui5lifecycledemo.main", {

    /** Specifies the Controller belonging to this View. 
    * In the case that it is not implemented, or that "null" is returned,
        * this View does not have a Controller.
    * @memberOf ui5lifecycledemo.main
    */ 
    getControllerName : function() {
        return "ui5lifecycledemo.main";
    },

    /** Is initially called once after the Controller has been instantiated. 
        * It is the place where the UI is constructed. 
    * Since the Controller is given to this method, its event handlers can 
        * be attached right away. 
    * @memberOf ui5lifecycledemo.main
    */ 
    createContent : function(oController) {

        console.log("createContent() of main view called...");
        
        // Create a Panel object 
        var mainPanel = new sap.ui.commons.Panel("mainPanel");
        
        // Create a Button object
        var exitButton = new sap.ui.commons.Button({
            id : "exitButton", // sap.ui.core.ID
            text : 'Exit and kill controller', // string
            press : [ function(oEvent) {
        
                // Commit suicide
                this.destroy();
                
                // Let the world know about it
                alert("View and Controller destroyed...");
                
            }, this ]
        });
                
        // Add the button to the main panel
        mainPanel.addContent(exitButton);
        
        return mainPanel;       
    }

});
      

Write Controller Logic

打开 main.controller.js 文件。 取消所有钩子方法的注释; 控制器的 onInit、onBeforeRendering、onAfterRendering 和 onExit 并将以下代码写入所有方法的主体中。

sap.ui.controller("ui5lifecycledemo.main", {

/**
* Called when a controller is instantiated and its View controls (if available) 
* are already created.
* Can be used to modify the View before it is displayed, to bind event handlers 
* and do other one-time initialization.
* @memberOf ui5lifecycledemo.main
*/
    onInit: function() {

        console.log("onInit() of controller called...");
    },

/**
* Similar to onAfterRendering, but this hook is invoked before the controller's 
* View is re-rendered
* (NOT before the first rendering! onInit() is used for that one!).
* @memberOf ui5lifecycledemo.main
*/
    onBeforeRendering: function() {

        console.log("onBeforeRendering() of controller called...");
    },

/**
* Called when the View has been rendered (so its HTML is part of the document). 
* Post-rendering manipulations of the HTML could be done here.
* This hook is the same one that SAPUI5 controls get after being rendered.
* @memberOf ui5lifecycledemo.main
*/
    onAfterRendering: function() {

        console.log("onAfterRendering() of controller called...");
    },

/**
* Called when the Controller is destroyed. Use this one to free resources 
* and finalize activities.
* @memberOf ui5lifecycledemo.main
*/
    onExit: function() {

        console.log("onExit() of controller called...");
    }
});
      

Deploy and Run Application

启动服务器并部署应用程序。 打开一个新的浏览器窗口(本示例使用 Chrome 浏览器)并打开开发者工具:

SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

然后在浏览器中打开如下网址 http://localhost:8088/UI5LifecycleDemo/index.html

请根据您的服务器配置使用端口号。

SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

加载 index.html 将在开发者工具控制台中打印日志。 可以看到首先调用视图的createContent()方法,然后是onInit()、onBeforeRendering(),最后是控制器的onAfterRendering()方法。 这些方法的目的在它们上面的注释中有很好的记录。 因此,我不详细讨论它们的目的。

SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

现在,单击退出并终止控制器按钮。这将调用视图上的 destroy() 方法。destroy() 方法清除与视图及其子元素关联的所有资源。因此,与视图关联的控制器也被销毁,因此它的 onExit() 方法被调用。

SAP UI5 视图控制器 View Controller 的生命周期方法 - Lifecycle methods

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