When I change a fragment I would like to compare the new one with the current one. If they are the same, it is not necessary to replace them.
I tried
public void displayFragment(Fragment fragment){
FragmentManager fm = getSupportFragmentManager();
Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
if(!currentFragment.equals(fragment))
getSupportFragmentManager().beginTransaction().addToBackStack(null).replace(R.id.content_frame, fragment).commit();
}
but it does not work and the fragment is changed even if the new one is the same
A solution ? Thanks
EDIT
The solution :
public void displayFragment(Fragment fragment){
FragmentManager fm = getSupportFragmentManager();
Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
if(!fragment.getClass().toString().equals(currentFragment.getTag())){
getSupportFragmentManager()
.beginTransaction()
.addToBackStack(null)
.replace(R.id.content_frame, fragment, fragment.getClass().toString()) // add and tag the new fragment
.commit();
}
}
3 Answers
One way to identify Fragments is to give them tags :
public void displayFragment(Fragment fragment, String tag){
FragmentManager fm = getSupportFragmentManager();
Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
if(!tag.equals(currentFragment.getTag())
getSupportFragmentManager()
.beginTransaction()
.addToBackStack(null)
.replace(R.id.content_frame, fragment, tag) // add and tag the new fragment
.commit();
}
edit : alternative version from psv's comment, using classnames as tag :
public void displayFragment(Fragment fragment){
FragmentManager fm = getSupportFragmentManager();
Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
if(!fragment.getClass().toString().equals(currentFragment.getTag()))
{
getSupportFragmentManager()
.beginTransaction()
.addToBackStack(null)
.replace(R.id.content_frame, fragment, fragment.getClass().toString()) // add and tag the new fragment
.commit();
}
}
Working Simple code in Kotlin. Here Fragment_Current() is a current fragment.
fun displayFragment(fm: Fragment) {
if(fm !is Fragment_Current){
supportFragmentManager.beginTransaction().replace(R.id.ContentFragmentRoot, fm).commit()
}
}
Based on @alex-fu comment, the code should be something like this:
public void displayFragment(Fragment fragment){
FragmentManager fm = getSupportFragmentManager();
Fragment currentFragment = fm.findFragmentById(R.id.content_frame);
if( !(fragment instanceof currentFragment) ) {
getSupportFragmentManager()
.beginTransaction()
.addToBackStack(null)
.replace(R.id.content_frame, fragment, fragment.getClass().toString()) // add and tag the new fragment
.commit();
}
}
