java – ArrayList. Remove does not work the first time it is called

I have an ArrayList < string > I use to store packageinfo (an example of an element in ArrayList is "com. Skype. Raider")

The initialization of the assembly members is as follows:

private List<String> pkgs;

And in the class constructor

pkgs = new ArrayList<>();

When I call Pkgs When I remove (string), it doesn't work, but when I try to delete it again and again, it will eventually work

Heirs: how do I test whether the deletion is valid (I edited the code to make it easier to read)

private void togglePackage(String selectedPackage,Check@R_867_2419@ chk_app){

    String m_pkg = selectedPackage.toString(); //redundant .toString()
    boolean checked = !chk_app.isChecked(); //check@R_867_2419@ boolean toggle

    if (checked && !pkgs.contains(m_pkg)) { //if not already in arraylist
        pkgs.add(m_pkg); //adding the newly checked package
    } else if (!checked && pkgs.contains(m_pkg)) { //if it needs to be removed
        pkgs.remove(m_pkg); //<-----------------------This works around the 3rd time i press the check@R_867_2419@
    }
    //Here i check if the string was actually removed from the arrylist
    //This following code will not be in production,i just used it for testing

    if (pkgs.contains(m_pkg)) {
        if (checked) {
            chk_app.setChecked(checked);//Success
        } else {
            chk_app.setChecked(!checked);//Failure
        }
     } else {
         if (!checked) {
            chk_app.setChecked(checked);//Success
         } else {
            chk_app.setChecked(!checked);//Failure
         }
     }
 }

This is an unedited onclick event

RelativeLayout rl_container = (RelativeLayout) child.findViewById(R.id.rl_container);
               rl_container.setTag(pkg);
               rl_container.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        String m_pkg = v.getTag().toString();
                        System.out.println("Pkg = "+m_pkg);
                        boolean checked = !chk_app.isChecked();
                        if (checked && !pkgs.contains(m_pkg)) {
                            pkgs.add(m_pkg);
                            System.out.println("Adding " + m_pkg);
                        } else if (!checked && pkgs.contains(m_pkg)) {
                            pkgs.remove(m_pkg);
                            System.out.println("Removing " + m_pkg);
                        }


                        if (pkgs.contains(m_pkg)) {
                            if (checked) {
                                System.out.println("Success");
                                chk_app.setChecked(checked);
                            } else {
                                System.out.println("Fail");
                                chk_app.setChecked(!checked);
                            }

                        } else {
                            if (!checked) {
                                System.out.println("Success");
                                chk_app.setChecked(checked);
                            } else {
                                System.out.println("Fail");
                                chk_app.setChecked(!checked);
                            }
                        }


                    }
                });

As an example, I have included the ArrayLists obtained from the iteration list And log output of my tests

List content:

com.sbg.mobile.phone

com.google.android.youtube 

com.e8tracks 

com.vlingo.midas 

com.google.android.googlequicksearch@R_867_2419@ 

com.truecaller

When I try to deselect "com. SBG. Mobile. Phone", the unedited code outputs logcat

12-18 10:37:25 ViewPostImeInputStage ACTION_DOWN
12-18 10:37:25 Pkg = com.sbg.mobile.phone
12-18 10:37:25 Removing com.sbg.mobile.phone
12-18 10:37:25 Fail
12-18 10:37:28 ViewPostImeInputStage ACTION_DOWN
12-18 10:37:28 Pkg = com.sbg.mobile.phone
12-18 10:37:28 Removing com.sbg.mobile.phone
12-18 10:37:28 Fail
12-18 10:37:30 ViewPostImeInputStage ACTION_DOWN
12-18 10:37:31 Pkg = com.sbg.mobile.phone
12-18 10:37:31 Removing com.sbg.mobile.phone
12-18 10:37:31 Fail
12-18 10:37:32 ViewPostImeInputStage ACTION_DOWN
12-18 10:37:32 Pkg = com.sbg.mobile.phone
12-18 10:37:32 Removing com.sbg.mobile.phone
12-18 10:37:32 Fail
12-18 10:37:33 ViewPostImeInputStage ACTION_DOWN
12-18 10:37:33 Pkg = com.sbg.mobile.phone
12-18 10:37:33 Removing com.sbg.mobile.phone 
12-18 10:37:33 Success

PS. this is my first question, so be gentle I am also grateful for any suggestions on how to improve the questions. I try to include all the necessary information, but if you need other information, please let me know

Solution

I think this may be a problem because ArrayList gives you the opportunity to store equal objects multiple times Maybe it's a good idea to use HashSet < string > Replace?

private Set<String> pkgs;