我在ionic 4项目中使用了角向布线（@ angular / router）来禁用ionic 4中的设备后退按钮prevent-default在我的代码中不起作用
app.component.ts
this.platform.backButton.subscribe(() => {
if (this.router.url === '/Login') {
this.util.presentAppExitAlert();
} else {
// event.preventDefault();
console.log("invoing url ", this.router.url);
}
});
});
我无法在此处禁用设备后退按钮的任何帮助
答案 0 :(得分：3)
2020年5月2日
这对我有用。
app.component.ts
async initializeApp(): Promise<void> {
await this.platform.ready();
this.platform.backButton.subscribeWithPriority(1, () => { // to disable hardware back button on whole app
});
}
答案 1 :(得分：2)
initializeApp() {
this.platform.ready().then(() => {
this.platform.backButton.subscribeWithPriority(9999, () => {
document.addEventListener('backbutton', function (event) {
event.preventDefault();
event.stopPropagation();
console.log('hello');
}, false);
});
this.statusBar.styleDefault();
});
}
答案 2 :(得分：1)
我发现了如何撤消它（赋予后退按钮以前的功能）：
您的观察者被推送到this.platform.backButton.observers数组。因此，您只需要弹出列表的最后一个元素即可：
this.platform.backButton.observers.pop();
希望对您有所帮助。
答案 3 :(得分：0)
这是管理设备后退按钮的另一个最佳选择：
manageBack()
{
this.platform.registerBackButtonAction(() => {
let activeVC = this.navCtrl.getActive();
console.log(activeVC.name)
let page = activeVC.instance;
console.log(page)
if (page instanceof PageName) {
try {
//this.platform.exitApp();
// this.navCtrl.popAll();
} catch (e) {
console.log("back action listener error :" + e);
}
}
// the default handler
});
}
答案 4 :(得分：0)
我找到了更好的方法来避免使用后退按钮设备，并在想要的任何页面上禁用后退
Azure Functions Core Tools (3.0.2245 Commit hash: 1d094e2f3ef79b9a478a1621ea7ec3f93ac1910d)
Function Runtime Version: 3.0.13139.0
[3/16/2020 6:02:11 PM] Building host: startup suppressed: 'False', configuration suppressed: 'False', startup operation id: 'a37bba12-9125-4af6-8c10-26daef57ef90'
[3/16/2020 6:02:11 PM] Reading host configuration file 'C:\Users\Peter\Desktop\UploadVideo\YoutubeUploadFunction\YoutubeUploadFunction\bin\Debug\netcoreapp3.0\host.json'
[3/16/2020 6:02:11 PM] Host configuration file read:
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "version": "2.0"
[3/16/2020 6:02:11 PM] }
[3/16/2020 6:02:11 PM] Reading functions metadata
[3/16/2020 6:02:11 PM] 1 functions found
[3/16/2020 6:02:11 PM] Loading startup extension 'AzureStorage'
[3/16/2020 6:02:11 PM] Loaded extension 'AzureStorage' (3.0.4.0)
[3/16/2020 6:02:11 PM] Initializing Warmup Extension.
[3/16/2020 6:02:11 PM] Initializing Host. OperationId: 'a37bba12-9125-4af6-8c10-26daef57ef90'.
[3/16/2020 6:02:11 PM] Host initialization: ConsecutiveErrors=0, StartupCount=1, OperationId=a37bba12-9125-4af6-8c10-26daef57ef90
[3/16/2020 6:02:11 PM] LoggerFilterOptions
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "MinLevel": "None",
[3/16/2020 6:02:11 PM] "Rules": [
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "ProviderName": null,
[3/16/2020 6:02:11 PM] "CategoryName": null,
[3/16/2020 6:02:11 PM] "LogLevel": null,
[3/16/2020 6:02:11 PM] "Filter": "<AddFilter>b__0"
[3/16/2020 6:02:11 PM] },
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "ProviderName": "Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics.SystemLoggerProvider",
[3/16/2020 6:02:11 PM] "CategoryName": null,
[3/16/2020 6:02:11 PM] "LogLevel": "None",
[3/16/2020 6:02:11 PM] "Filter": null
[3/16/2020 6:02:11 PM] },
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "ProviderName": "Microsoft.Azure.WebJobs.Script.WebHost.Diagnostics.SystemLoggerProvider",
[3/16/2020 6:02:11 PM] "CategoryName": null,
[3/16/2020 6:02:11 PM] "LogLevel": null,
[3/16/2020 6:02:11 PM] "Filter": "<AddFilter>b__0"
[3/16/2020 6:02:11 PM] }
[3/16/2020 6:02:11 PM] ]
[3/16/2020 6:02:11 PM] }
[3/16/2020 6:02:11 PM] FunctionResultAggregatorOptions
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "BatchSize": 1000,
[3/16/2020 6:02:11 PM] "FlushTimeout": "00:00:30",
[3/16/2020 6:02:11 PM] "IsEnabled": true
[3/16/2020 6:02:11 PM] }
[3/16/2020 6:02:11 PM] SingletonOptions
[3/16/2020 6:02:11 PM] {
[3/16/2020 6:02:11 PM] "LockPeriod": "00:00:15",
[3/16/2020 6:02:11 PM] "ListenerLockPeriod": "00:00:15",
[3/16/2020 6:02:11 PM] "LockAcquisitionTimeout": "10675199.02:48:05.4775807",
[3/16/2020 6:02:12 PM] "LockAcquisitionPollingInterval": "00:00:05",
[3/16/2020 6:02:12 PM] "ListenerLockRecoveryPollingInterval": "00:01:00"
[3/16/2020 6:02:12 PM] }
[3/16/2020 6:02:12 PM] QueuesOptions
[3/16/2020 6:02:12 PM] {
[3/16/2020 6:02:12 PM] "BatchSize": 16,
[3/16/2020 6:02:12 PM] "NewBatchThreshold": 8,
[3/16/2020 6:02:12 PM] "MaxPollingInterval": "00:00:02",
[3/16/2020 6:02:12 PM] "MaxDequeueCount": 5,
[3/16/2020 6:02:12 PM] "VisibilityTimeout": "00:00:00"
[3/16/2020 6:02:12 PM] }
[3/16/2020 6:02:12 PM] BlobsOptions
[3/16/2020 6:02:12 PM] {
[3/16/2020 6:02:12 PM] "CentralizedPoisonQueue": false
[3/16/2020 6:02:12 PM] }
[3/16/2020 6:02:12 PM] HttpOptions
[3/16/2020 6:02:12 PM] {
[3/16/2020 6:02:12 PM] "DynamicThrottlesEnabled": false,
[3/16/2020 6:02:12 PM] "MaxConcurrentRequests": -1,
[3/16/2020 6:02:12 PM] "MaxOutstandingRequests": -1,
[3/16/2020 6:02:12 PM] "RoutePrefix": "api"
[3/16/2020 6:02:12 PM] }
[3/16/2020 6:02:12 PM] Starting JobHost
[3/16/2020 6:02:12 PM] Starting Host (HostId=desktopgq271u4-950774370, InstanceId=16bc66b5-e751-4c00-b383-6f705e303c13, Version=3.0.13139.0, ProcessId=5656, AppDomainId=1, InDebugMode=False, InDiagnosticMode=False, FunctionsExtensionVersion=(null))
[3/16/2020 6:02:12 PM] Loading functions metadata
[3/16/2020 6:02:12 PM] 1 functions loaded
[3/16/2020 6:02:12 PM] Generating 1 job function(s)
[3/16/2020 6:02:12 PM] Found the following functions:
[3/16/2020 6:02:12 PM] YoutubeUploadFunction.Function1.Run
[3/16/2020 6:02:12 PM]
[3/16/2020 6:02:14 PM] Initializing function HTTP routes
[3/16/2020 6:02:14 PM] No HTTP routes mapped
[3/16/2020 6:02:14 PM]
[3/16/2020 6:02:14 PM] Host initialized (2033ms)
[3/16/2020 6:02:14 PM] Host started (2485ms)
[3/16/2020 6:02:14 PM] Job host started
Hosting environment: Production
Content root path: C:\Users\Peter\Desktop\UploadVideo\YoutubeUploadFunction\YoutubeUploadFunction\bin\Debug\netcoreapp3.0
Now listening on: http://0.0.0.0:7071
Application started. Press Ctrl+C to shut down.
[3/16/2020 6:02:19 PM] Host lock lease acquired by instance ID '000000000000000000000000A74A8599'.
C:\Users\Peter\AppData\Local\AzureFunctionsTools\Releases\3.4.1\cli_x64\func.exe (process 5656) exited with code -1.
To automatically close the console when debugging stops, enable Tools->Options->Debugging->Automatically close the console when debugging stops.
Press any key to close this window . . .
答案 5 :(得分：0)
可能需要提及使用CSS only slideshow处理后退按钮，该操作会禁用文档中所述的默认后退按钮行为：
/**
* Listen for the hardware back button event (Android only). Listening for this event will disable the
* default back button behaviour, so you might want to call `window.history.back()` manually.
* If you want to close the app, call `App.exitApp()`.
*/
addListener(eventName: 'backButton', listenerFunc: (data: AppUrlOpen) => void): PluginListenerHandle;
用法：
import { Plugins, AppState } from '@capacitor/core';
const { App } = Plugins;
App.addListener('backButton', (data: AppUrlOpen) => {
console.log('User pushed the back button, default behaviour has been overiden');
});
答案 6 :(得分：0)
您可以为特定页面实现禁用硬件后退按钮。在ionic 4中使用以下代码。
ionViewDidEnter() {
this.backbutton = this.platform.backButton.observers.pop();
}
ionViewWillLeave() {
this.platform.backButton.observers.push(this.backbutton);
}
答案 7 :(得分：0)
在ionic 5中使用LoadingController时，禁用硬件后退按钮。请参考前两个答案并将其合并到加载控制器代码中
import {
LoadingController,
Platform
} from '@ionic/angular';
constructor(public platform: Platform, private loadingController: LoadingController) {}
async presentLoading() {
this.platform.backButton.subscribeWithPriority(10, () => {
document.addEventListener('backbutton', () => {}, false);
});
const loading = await this.loadingController.create({
spinner: 'circles',
keyboardClose: true,
message: 'Please Wait'
}).then((res) => {
res.onDidDismiss().then((d) => {
this.platform.backButton.observers.pop();
})
return res.present()
})
return loading;
}