清除fragment页面数据（重新加载布局）

package com.example.yzq.testfragment; import android.content.res.Configuration; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.design.widget.BottomNavigationView; import android.support.v4.app.Fragment; import android.support.v7.app.AppCompatActivity; import android.view.MenuItem; import android.widget.FrameLayout; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener { private FrameLayout contentLayout;//容器 private BottomNavigationView mainBottomView;//底部导航 /*三个fragment*/ private HomeFragment homeFragment; private DashboardFragment dashboardFragment; private NoticeFragment noticeFragment; /*三个fragment对应的key*/ private static final String HOME_FRAGMENT_KEY = "homeFragment"; private static final String DASHBOARD_FRAGMENT_KEY = "DashboardFragment"; private static final String NOTICE_FRAGMENT_KEY = "NoticeFragment"; private List<Fragment> fragmentList = new ArrayList<>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); L.i("MainActivity onCreate"); initView(); /*savedInstanceState是否为空 不为空则取出fragment 为空则初始化fragment*/ if (savedInstanceState != null) { /*获取保存的fragment 没有的话返回null*/ homeFragment = (HomeFragment) getSupportFragmentManager().getFragment(savedInstanceState, HOME_FRAGMENT_KEY); dashboardFragment = (DashboardFragment) getSupportFragmentManager().getFragment(savedInstanceState, DASHBOARD_FRAGMENT_KEY); noticeFragment = (NoticeFragment) getSupportFragmentManager().getFragment(savedInstanceState, NOTICE_FRAGMENT_KEY); addToList(homeFragment); addToList(dashboardFragment); addToList(noticeFragment); } else { initFragment(); } } private void addToList(Fragment fragment) { if (fragment != null) { fragmentList.add(fragment); } L.i("fragmentList数量" + fragmentList.size()); } private void initView() { contentLayout = (FrameLayout) findViewById(R.id.bottom_nav_content); mainBottomView = (BottomNavigationView) findViewById(R.id.mainBottomView); mainBottomView.setOnNavigationItemSelectedListener(this); } private void initFragment() { /* 默认显示home fragment*/ L.i("initFragment"); homeFragment = new HomeFragment(); showFragment(homeFragment, HOME_FRAGMENT_KEY); } /*显示fragment*/ private void showFragment(Fragment fragment, String tag) { /*先判断fragment是否被添加过*/ if (!fragment.isAdded()) { L.i(fragment+"没有添加过 添加"); getSupportFragmentManager().beginTransaction().add(R.id.bottom_nav_content,fragment, tag).commit(); fragmentList.add(fragment); } /*不可见*/ if (!fragment.isVisible()) { for (Fragment frag : fragmentList) { if (frag != fragment) { /*先隐藏其他fragment*/ L.i("隱藏" + frag); getSupportFragmentManager().beginTransaction().hide(frag).commit(); } } getSupportFragmentManager().beginTransaction().show(fragment).commit(); } } @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { switch (item.getItemId()) { case R.id.navigation_home: if (homeFragment == null) { L.i("homeFragment 为空 创建"); homeFragment = new HomeFragment(); } showFragment(homeFragment, HOME_FRAGMENT_KEY); break; case R.id.navigation_dashboard: if (dashboardFragment == null) { L.i("dashboardFragment 为空 创建"); dashboardFragment = new DashboardFragment(); } showFragment(dashboardFragment, HOME_FRAGMENT_KEY); break; case R.id.navigation_notifications: if (noticeFragment == null) { L.i("noticeFragment 为空 创建"); noticeFragment = new NoticeFragment(); } showFragment(noticeFragment, HOME_FRAGMENT_KEY); break; } return true; } /*重新加载布局*/ public void reLoadFragView(){ /*现将该fragment从fragmentList移除*/ if (fragmentList.contains(dashboardFragment)){ fragmentList.remove(dashboardFragment); } /*从FragmentManager中移除*/ getSupportFragmentManager().beginTransaction().remove(dashboardFragment).commit(); /*重新创建*/ dashboardFragment=new DashboardFragment(); /*添加到fragmentList*/ fragmentList.add(dashboardFragment); /*显示*/ showFragment(dashboardFragment,DASHBOARD_FRAGMENT_KEY); } @Override protected void onSaveInstanceState(Bundle outState) { L.i("MainActivity onSaveInstanceState"); /*fragment不为空时 保存*/ if (homeFragment != null) { getSupportFragmentManager().putFragment(outState, HOME_FRAGMENT_KEY, homeFragment); } if (dashboardFragment != null) { getSupportFragmentManager().putFragment(outState, DASHBOARD_FRAGMENT_KEY, dashboardFragment); } if (noticeFragment != null) { getSupportFragmentManager().putFragment(outState, NOTICE_FRAGMENT_KEY, noticeFragment); } super.onSaveInstanceState(outState); } }