内容纲要
底部导航栏切换Fragment进行显示
创建Fragment对象
通常会有多个Fragment用于切换
用Fragment[] fragments保存为集合
private FrameLayout frame_home;
private Fragment[] fragments;
private HomeFragment homeFragment;
private int lastfragment = 0;
显示Fragment对象
加载Fragment视图
private void initView() {
//加载Fragment
homeFragment = new HomeFragment();
//Fragments集合
fragments = new Fragment[]{homeFragment};
//加载FrameLayout布局
frame_home = (FrameLayout) findViewById(R.id.frame_home);
//设置fragment到布局
getSupportFragmentManager().beginTransaction().replace(R.id.frame_home,homeFragment).show(homeFragment).commit();
}
切换Fragment
管理多个Fragment并切换
切换到指定Fragment
//切换fragment
private void switchFragment(int lastfragment, int index) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
//隐藏上个Fragment
transaction.hide(fragments[lastfragment]);
if (!fragments[index].isAdded()) {
transaction.add(R.id.frame_home, fragments[index]);
}
transaction.show(fragments[index]).commitAllowingStateLoss();
}
底部导航栏点击事件监听器
//底部导航栏点击响应事件
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.nav_home:
if (lastfragment != 0) {
switchFragment(lastfragment, 0);
lastfragment = 0;
}
ToastUtil.showToast(getApplicationContext(), "点击了nav_home");
return true;
case R.id.nav_zoom:
// if (lastfragment != 1) {
// switchFragment(lastfragment, 1);
// lastfragment = 1;
// }
ToastUtil.showToast(getApplicationContext(), "点击了nav_zoom");
return true;
case R.id.nav_user:
ToastUtil.showToast(getApplicationContext(), "点击了nav_user");
return true;
default:
break;
}
return false;
}
};
