Setting icons when a tab is selected

Question

I have this 2 arrays :

final int[] tabSelected = {
 R.drawable.iconWhite0,
 R.drawable.iconWhite1,
 R.drawable.iconWhite2,
 R.drawable.iconWhite3,
 R.drawable.iconWhite4};
final int[] tabsUnselected = {
 R.drawable.iconBlack0,
 R.drawable.iconBlack1,
 R.drawable.iconBlack2,
 R.drawable.iconBlack3,
 R.drawable.iconBlack4};

I just don't understand how I can simplify this, by making a for loop ..although I am sure it is very easy, I just don't see it.

 @Override
 public void onPageSelected(int position) {
 switch (position) {
 case 0:
 tabLayout.getTabAt(0).setIcon(tabSelected[0]);
 tabLayout.getTabAt(1).setIcon(tabsUnselected[1]);
 tabLayout.getTabAt(2).setIcon(tabsUnselected[2]);
 tabLayout.getTabAt(3).setIcon(tabsUnselected[3]);
 tabLayout.getTabAt(4).setIcon(tabsUnselected[4]);
 break;
 case 1:
 tabLayout.getTabAt(0).setIcon(tabsUnselected[0]);
 tabLayout.getTabAt(1).setIcon(tabSelected[1]);
 tabLayout.getTabAt(2).setIcon(tabsUnselected[2]);
 tabLayout.getTabAt(3).setIcon(tabsUnselected[3]);
 tabLayout.getTabAt(4).setIcon(tabsUnselected[4]);
 break;
 case 2:
 tabLayout.getTabAt(0).setIcon(tabsUnselected[0]);
 tabLayout.getTabAt(1).setIcon(tabsUnselected[1]);
 tabLayout.getTabAt(2).setIcon(tabSelected[2]);
 tabLayout.getTabAt(3).setIcon(tabsUnselected[3]);
 tabLayout.getTabAt(4).setIcon(tabsUnselected[4]);
 break;
 case 3:
 tabLayout.getTabAt(0).setIcon(tabsUnselected[0]);
 tabLayout.getTabAt(1).setIcon(tabsUnselected[1]);
 tabLayout.getTabAt(2).setIcon(tabsUnselected[2]);
 tabLayout.getTabAt(3).setIcon(tabSelected[3]);
 tabLayout.getTabAt(4).setIcon(tabsUnselected[4]);
 break;
 default:
 tabLayout.getTabAt(0).setIcon(tabsUnselected[0]);
 tabLayout.getTabAt(1).setIcon(tabsUnselected[1]);
 tabLayout.getTabAt(2).setIcon(tabsUnselected[2]);
 tabLayout.getTabAt(3).setIcon(tabsUnselected[3]);
 tabLayout.getTabAt(4).setIcon(tabSelected[4]);
 break;
 }
 }

• r3dm4n: I've edited my post. It's Android SDK (Java)
• BCdotWEB: As we all want to make our code more efficient or improve it in one way or another, try to write a title that summarizes what your code does, not what you want to get out of a review. Please see How to get the best value out of Code Review - Asking Questions for guidance on writing good question titles.

Answer 1

You check whether the index of the tab equals the position. If this is the case, use the selected icon, otherwise use the unselected one:

for(int i = 0; i < 5; i++) { // maybe replace 5 with a constant declaration...
 if(i == position)
 tabLayout.getTabAt(i).setIcon(tabSelected[i]);
 else
 tabLayout.getTabAt(i).setIcon(tabsUnselected[i]);
}

Answer 2

This is how i'd do it:

@Override
public void onPageSelected(int position) {
 int size = 4;
 position = Math.min(position, size);
 for(int i = 0; i <= size; i++){
 if(i == position){
 tabLayout.getTabAt(i).setIcon(tabSelected[i]);
 }
 else {
 tabLayout.getTabAt(i).setIcon(tabsUnselected[i]);
 }
 }
}

Math.min(position,4) ensures this works even if position is bigger 4, as you handeled with the default case. Don't know what more to tell atm, feel free to ask!

I also added a size value which you can set static or dynamic for faster adaption in case size changes. This will keep the value in one place so its easier to maintain.

Edit:

Another approach:

@Override
public void onPageSelected(int position) {
 int size = 4;
 position = Math.min(position, size);
 for(int i = 0; i <= size; i++){
 tabLayout.getTabAt(i).setIcon(tabsUnselected[i]);
 }
 tabLayout.getTabAt(position).setIcon(tabSelected[position]);
}

even less complex but depending on how slow overwriting a Tab is it might really slow down the code, i doubt it will have significant impact.

Edit2:

Florian Salihovic kindly recommends: "size could be set to TabLayout#getTabCount()". You should have a look if this works for you.

• Florian Salihovic: I was about to post the second version as well. size could be set to TabLayout#getTabCount().