当您的应用程序在后台时，离子如何通过摇动打开您的应用程序？

Question

I am building an emergency app, and one of the features is to open the app on shake, now I understand that app must be in the background running.

and I am using cordova-background-mode and cordova shake and the everything works,

however when the phone is on the home screen(the app is just minimized). the app does not launch when I shake, but when I reopen the app by tapping on its icon, it does show that a shake event occurred and opens another app that I am using to test.

How can I get it to open the app on shake when the app is in the background?

Here is my code

this.platform.ready().then((e) => {
      this.backgroundMode.enable();
      this.backgroundMode.setEnabled(true);

      this.statusBar.styleDefault();
      this.splashScreen.hide();

        this.shake.startWatch().subscribe(() => {
          console.log(`watching...${e}`);
          alert('shake');
          const options: AppLauncherOptions = {
          }

           if(this.platform.is('ios')) {
             options.uri = 'fb://'
           } else {
             options.packageName = 'com.facebook.katana'
           }

           this.appLauncher.canLaunch(options).then((launch:Boolean)=>{
             if(launch){
               this.appLauncher.launch(options).then(()=>{
                 alert('Launched')
               },
               (err)=>{
                alert(JSON.stringify(err))
               })
             }else{
               alert(JSON.stringify("unable to launch app"));
             }
           },(err)=>{
             alert(JSON.stringify(err));
           })  

          });

Edit

this is my code and it works, however the problem is, if I open another app, ie whatsapp but it can be any app, and close it, and then if I shake the phone, it opens the last app I was using instead of launching my app.

 startBackgroundMode(){          

    this.backgroundMode.enable();
    this.backgroundMode.overrideBackButton();           

    this.backgroundMode.on('activate').subscribe(value => {
        this.backgroundMode.disableWebViewOptimizations();  
        this.shakePhone();   
    });
}
shakePhone(){
  this.shake.startWatch().subscribe(() => {
    console.log(`watching...`);                      
    this.openApp();

    });
}
  openApp(){  

    const options: AppLauncherOptions = {
    }
    options.packageName = 'this is my app's package name'


  this.appLauncher.launch(options);

  }

Answer 1

Various APIs like playing media or tracking GPS position in background might not work while in background even the background mode is active. To fix such issues the plugin provides a method to disable most optimizations done by Android/CrossWalk.

cordova.plugins.backgroundMode.on('activate', function() {
   cordova.plugins.backgroundMode.disableWebViewOptimizations(); 
});

Note: Calling the method led to increased resource and power consumption.

Also need to use following

The plugin fires an event each time its status has been changed. These events are enable, disable, activate, deactivate and failure.

also need to check this.shake.startWatch() in background activated mode

cordova.plugins.backgroundMode.on('EVENT', function);

To remove an event listeners:

cordova.plugins.backgroundMode.un('EVENT', function); 

Answer 2

I believe this is not the right way which you are trying. If you could employ java in order to develop your application then it was possible to use the SensorManager to detect a shake. Now you are working with ionic and the solution is taking advantage of device-motion plugin.

Note that solutions like ionic are not as powerful as main development environment (java or kotlin with android studio) although they are more strong at interface design since they take advantage of browser based applications (web kit). So you have to consider browser restrictions too, so employing sth like devicemotion EventListener may not work on all operating systems.

If you are working on an important application choose the main solution to avoid restrictions.

Answer 3

Knowing that you are using ionic 4, one way to achieve this result is by developing one custom plugin, but with ionic capacitor instead of cordova. Capacitor made easier to build your custom plugins and makes the native code more accessible for those who hasnt built any plugins yet.

The links below show how you implement a custom plugin for both ios and android.
How to embed third party framework on ionic capacitor custom plugin?
How to embed an Android library (AAR file) into a capacitor plugin?

I point this solution as a alternative. I know that the workload would be much higher and that the project already have plenty of cordova plugins.