Removing item from Java List in Android

Question

I'm having trouble with the following code.

I am getting the the index of item and using it. Now I want to remove it's position from the list so that it doesn't get the same position again, but when I call the method below the app crashes, and when I delete the line myList.remove(randomIndex); it runs good. Is something wrong with this line?

public void showtime() {

     Random rand = new Random();
     randomIndex = rand.nextInt(myList.size());

     randomName = myList.get(randomIndex);
     txtView.setText(randomName);

     if (randomIndex==1)) {
         imgLabel.setImageResource(R.drawable.Label1);
     }
     if (randomIndex==2)) {
         imgLabel.setImageResource(R.drawable.Label2);
     }
     if (randomIndex==3)) {
         imgLabel.setImageResource(R.drawable.Label3);
     }

     myList.remove(randomIndex);
  }

Answer 1

Ensure that:

1- myList is an ArrayList;

2- When this method is called, myList has almost an element

Each of your if statements has a syntax error. They have an extra )

if (randomIndex==1) {
     imgLabel.setImageResource(R.drawable.Label1);
 }
 if (randomIndex==2) {
     imgLabel.setImageResource(R.drawable.Label2);
 }
 if (randomIndex==3) {
     imgLabel.setImageResource(R.drawable.Label3);
 }

Answer 2

当您从列表中删除项目时，请确保它不应该是它必须是请试试这个....

Answer 3

它应该是

    randomIndex = rand.nextInt(myList.size());

Answer 4

You can check that the generated index is within the list bounds and avoid the crash like this

randomIndex = rand.nextInt(myList.size()-1);

if(randomIndex <= myList.size()-1){
 myList.remove(randomIndex)
};