Dart development skills

Hello everyone , I'm Xiao pan , This is my first article , I am very sorry that my writing ability is not good .

In this article , I would like to share my experience of adding currency formats to strings without packages , And the use of  Flutter  stay  Android 12  Verify on  Android  App Links

Dart  Simple extension of string currency format in

void main() {
 print("1000".currency());
 print("1300000".currency());
 print("1005000".currency(symbol: '£'));
 print("1000000".currency(symbol: '€'));
}
extension StringFormatter on String{
 String currency({String symbol = "\$"}) {
  
   int step = 1;
   String val = this;
    
   for (var i = val.length-1; i >=0; i--) {
     if (i - 2*step > 0) {
        
       val = val.replaceRange(i-2*step, i-2*step, ",");
       step++;
     }
   }
    
   return "$symbol$val";
 }
}
​

Use  Flutter  stay  Android 12  Verify on  Android  App Links

If you set up an application link in your application / General Links , You may have noticed that this does not always apply to certain users . Sometimes this is because by default , The device does not allow applications to open from a browser or e-mail  URL.

With  Android 12  Release ,Google  Added a name called

DomainVerificationManager

The new  API . this  API  It can help you check whether your application is connected with one or more  URL  Related to .

I found a plug-in , Can help you through  Flutter  Visit some of the new  API  function .

You can go to

Here to find

domain_verification_manager

plug-in unit

How it works ？

This plug-in is only available for  API  Level  31  Or higher  Android. however , You can safely add packages to cross platform applications . You can do it

isSupported

Check to verify that the current platform can be used / Version combination .

To verify that you can use  API, Please use

isSupported

await DomainVerificationManager.isSupported;

You can visit  3  Status ：

• Verified ： Passed  Android  Domain to which link validation applies

• Selected ： Failed validation , But the user manually associates the domain of the application .

• nothing ： Any other domain

Domain is where you  AndroidManifest  Fields defined in .

Each of these will return a list of domains suitable for that state .

await DomainVerificationManager.domainStageVerified;
await DomainVerificationManager.domainStageSelected;
await DomainVerificationManager.domainStageNone;

If you see that the domain does not exist , It may mean that there is a problem in the verification process .

To check what's wrong , You can use here

Explain the command line tools .

Use these , You can prompt the user to select your application to open the domain .

Change state

up to now , There is no direct way to change the state . This is what users must do .

The plug-in provides a simple way to open the application directly “ The default ” Set up .

await DomainVerificationManager.domainRequest();

I hope this plug-in can help you ！

Conclusion

dart  The extension

It's a function , Can help you add functions to other classes that you don't write . I'm here for

String

Class writing extensions

ok , Let's explain the code ：

We have from the end to the beginning of the string  for  loop , Because the currency splitter starts from writing the price

We need every  3  Characters add a character , for example ：“,” I use  replaceRange  Method to insert characters in a special index .

How to find the correct index to insert characters ？  I am considered to have an initial value of  1  The variables of the step . ok , We need to check what we returned before  3  Whether characters are greater than  0, If it is true , We can do it at every  3  Insert a symbol in characters . If we want to, for example  4 char  It only needs to use  3  Replace  2  Just fine .

Then I introduced the use of  Flutter  stay  Android 12  Verify on  Android  The method of applying Links , I don't know if it suits your taste .

well , That's all for today ！