Launchpad 标题后退按钮的事件处理程序

Question

I need to overwrite the event of Launchpad Header Back Button in certain cases. I tried lots of things like:

 try { sap.ui.getCore().byId("backBtn").attachPress(this, function(oEvent) { oEvent.preventDefault(); }.bind(this)); } catch (err) { console.log(err); }

or

 $('body').mousedown(function(e) { var oTarget = $(e.target); console.log(oTarget[0].offsetParent.id); console.log(oTarget[0]); if (oTarget[0].offsetParent.id === "backBtn") { console.log("prevent"); e.preventDefault(); e.stopPropagation(); return false; } }.bind(this));

In these codes I just tried to prevent the navi, getting back. Didn't work. I want to navigate to certain views in certain cases. For example:

if user is in view 3 -> click Launchpad Back Button -> navigate to view 1 (not the previous navigation target)

But I couldn't stop navigation mechanism to go back to previous target.

I'd appreciate any help or ideas.

Answer 1

First you need to register the ShellUIService in your manifest.json

In manifest.json under sap.ui5:

...
"sap.ui5": {
     ...
     "services": {
        "ShellUIService": {
            "factoryName": "sap.ushell.ui5service.ShellUIService"
        }
    }
    ...
}
...

then you can override the default behavior in your controller (or from the component)

this.getOwnerComponent().getService("ShellUIService").then(function(oShellService) {
    oShellService.setBackNavigation(function() {
        //either do nothing to disable it, or add your own back nav logic
    })

})

Answer 2

I've had trouble preventing the default Fiori shell(launchpad) actions in the past myself. A different approach might be to use sap.ui.core.routing's HashChanger and/or the Router (presumably you are already using a router in your app).

It's not incredibly elegant, but you could use the HashChanger's hashChanged event to determine if your conditions are met (ie when old hash = view 3's pattern) you could fire a Router.navTo("view1sRouteName") . You could also instantiate a History sap.ui.core.routing object to get for certain whether the direction is forward or backward using History.getDirection() .

Make sure you read the APIs on the History and HashChanger's dependencies so that you are instantiating at the right time.

Answer 3

I did not get it to work reliably with the most voted answer.

This might be against better advice in the documentation, but is working for me:

...
    "sap/ushell/ui5service/ShellUIService"
], function (BaseController, JSONModel, formatter, IconPool, ShellUIService) {
...
onInit: function () {
    this.oShellUIService = new ShellUIService({
                    scopeObject: this.getOwnerComponent(),
                    scopeType: "component"
                });
        this.oShellUIService.setBackNavigation(this._navBack.bind(this));

...