How to handle back button on Ionic 2

Question

How can I handle the back button action on Ionic 2?

I want to be able to know what to do depending on which page is being shown to the user.

I didn\'t find a

Answer 1

you can try this functions :

registerBackButton() {
        this.platform.registerBackButtonAction(() => {
            if (this.menu.isOpen()) {
                console.log("Menu is open!", "loggedInMenu");
                this.menu.close();
                console.log("this.menu.isOpen(): " + JSON.stringify(this.menu.isOpen()));
                return;
            }
            console.log("Checking for other pages");

            let checkHomePage = true;
            let max = Globals.navCtrls.length;
            for (let i = 0; i < Globals.navCtrls.length; i++) {
                let n = Globals.navCtrls[i];
                if (n) {
                    if (n.canGoBack()) {
                        console.log("Breaking the loop i: " + JSON.stringify(i));
                        let navParams = n.getActive().getNavParams();
                        if (navParams) {
                            console.log("navParams exists");
                            let resolve = navParams.get("resolve");
                            if (resolve) {
                                n.pop().then(() => resolve({}));
                            } else {
                                n.pop();
                            }
                        } else {
                            n.pop();
                        }
                        checkHomePage = false;
                        return;
                    }
                } else console.log("n was null!");
            }

            if (this.nav.getActive().instance instanceof TabsPage && !this.nav.canGoBack()) {
                let popPageVal = this.backbuttonService.popPage();
                console.log("popPageVal: " + JSON.stringify(popPageVal));
                if (popPageVal >= 0) {
                    console.log("Switching the tab to: ", popPageVal);
                    this.switchTab(popPageVal);
                } else {
                    console.log("Last page is HomePage");

                    if (this.alert) {
                        this.alert.dismiss();
                        this.alert = null;
                    } else {
                        this.showAlert();
                    }
                }
            } else {
                console.log("Last page is not HomePage");
                if (this.nav.canGoBack()) {
                    console.log("We can go back!");
                    this.nav.pop();
                }
            }
        });
    }

    showAlert() {
        this.alert = this.alertController.create({
            title: "Exit?",
            message: "Are you sure you want to exit?",
            buttons: [
                {
                    text: "Cancel",
                    role: "cancel",
                    handler: () => {
                        this.alert = null;
                    }
                },
                {
                    text: "Exit",
                    handler: () => {
                        this.platform.exitApp();
                    }
                }
            ]
        });
        this.alert.present();
    }

    switchTab(tabIndex) {
        if (Globals.tabs && tabIndex >= 0) {
            console.log("Switch condition met");
            Globals.tabIndex = tabIndex;
            Globals.tabs.select(tabIndex);
            Globals.tabs.selectedIndex = tabIndex;
        }
    }

I hope its works with you.