如何检查警报是可见的android

Question

how to check if my alert is already showing on screen ?

 AlertDialog.Builder alert = new AlertDialog.Builder(this);

 alert.show();

I can maintain state by adding a flag in my code to set and reset, but if there is already a method that I can re use ?

Answer 1

There is no isShowing() method on the AlertDialog.Builder class. There is one on the Dialog class though.

AlertDialog.Builder

Dialog

An AlertDialog.Builder is used to create an AlertDialog. Once you have an instance of an AlertDialog, you can determine whether or not it is still showing by then calling isShowing() on it.

AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
AlertDialog alertDialog = alertDialogBuilder.create();

if(!alertDialog.isShowing()){   
  //if its visibility is not showing then show here 
   alertDialog.show();       
 }else{
  //do something here... if already showing       
  }

Answer 2

Yes you can check it with isShowing(); method it's documented in the Android Documentation too

But in your case you need to catch the AlertDialog that build by the AlertDialog.Builder first.
so your code should be like this

AlertDialog alertDialog;

function showDialog() {
    if(alertDialog == null) { 
        //Initial Creation will always show 
        //or you can just use create() if you don't want to show it at initial creation
        AlertDialog.Builder alert = new AlertDialog.Builder(this);
        AlertDialog alertDialog = alert.show();
    else {
        if(alertDialog.isShowing()) {
             alertDialog.hide();
        } else {
             alertDialog.show();
        }
    }
}

Answer 3

Use this:

AlertDialog alertDialog = alert.create();

//to check if its being shown
if(!alertDialog.isShowing()){
    //do something
    alertDialog.show();
}

It will return true if currently that alert dialog is being shown. So in your case, check if it returns false , and then show it.

Hope it helps.

Answer 4

您可以使用对话框的isShowing方法，或者您可以在创建警告对话框标志为0时显示标志，并在显示后将其设置为1。