用fragment中的setUserVisibleHint这个方法即可。
private boolean hasLoadedOnce = false; //your boolean field
@Override
public void setUserVisibleHint(booleanisVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (this.isVisible()) {
// we check that the fragment is becomingvisible
if (isVisibleToUser &&!hasLoadedOnce) {
//do something
}
}
}
}