摘自Fragmentation官方知乎案例
先跟着原作者把案例写一遍,再去放飞自我
1 集成Fragmentation
// Fragmentation https://github.com/YoKeyword/Fragmentation
compile 'me.yokeyword:fragmentation:1.3.6'
compile 'me.yokeyword:fragmentation-swipeback:1.3.6'
compile 'me.yokeyword:eventbus-activity-scope:1.1.0'
compile 'org.greenrobot:eventbus:3.0.0'
2 在Application中注册Fragmentation
public class MyApplication extends Application {
@Override
public void onCreate() {
super.onCreate();
// 建议在Application里初始化
Fragmentation.builder()
// BUBBLE显示悬浮球 ; SHAKE: 摇一摇唤出 ; NONE：隐藏
.stackViewMode(Fragmentation.BUBBLE)
.debug(BuildConfig.DEBUG)
.install();
}
}
<application
android:name=".MyApplication"
... >
</application>
3 创建BaseFragment,监听返回键退出
public class BaseMainFragment extends SupportFragment {
protected OnBackToFirstListener _mBackToFirstListener;
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnBackToFirstListener) {
_mBackToFirstListener = (OnBackToFirstListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnBackToFirstListener");
}
}
@Override
public void onDetach() {
super.onDetach();
_mBackToFirstListener = null;
}
// 对返回键进行监听
@Override
public boolean onBackPressedSupport() {
// 当前栈中的Fragment个数大于1
if(getChildFragmentManager().getBackStackEntryCount()>1){
popChild();
}else{
// 当这个Fragment是第一个导航页,直接退出
if(this instanceof ZhihuFirstFragment){
_mActivity.finish();
}else{
// 返回到第一个导航页
_mBackToFirstListener.OnBackToFirstFragment();
}
}
return true;
}
public interface OnBackToFirstListener {
void OnBackToFirstFragment();
}
}
4 创建4个Fragment,以及他们的子Fragment
/**
* 第一个导航页
*
* Created by wxyass on 2018/8/17.
*/
public class ZhihuFirstFragment extends BaseMainFragment{
public static ZhihuFirstFragment newInstance(){
Bundle args = new Bundle();
ZhihuFirstFragment fragment = new ZhihuFirstFragment();
fragment.setArguments(args);
return fragment;
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_first,container,false);
return view;
}
@Override
public void onLazyInitView(@Nullable Bundle savedInstanceState) {
super.onLazyInitView(savedInstanceState);
if(findChildFragment(ZhihuFirstFragment.class)==null){
loadRootFragment(R.id.fl_first_container, FirstHomeFragment.newInstance());
}
}
}
// fragment_first.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:id="@+id/fl_first_container"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
/**
* 第一个导航页的子Fragment
*
* Created by wxyass on 2018/8/17.
*/
public class FirstHomeFragment extends BaseMainFragment{
public static FirstHomeFragment newInstance(){
Bundle args = new Bundle();
FirstHomeFragment fragment = new FirstHomeFragment();
fragment.setArguments(args);
return fragment;
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_first_home,container,false);
return view;
}
@Override
public void onLazyInitView(@Nullable Bundle savedInstanceState) {
super.onLazyInitView(savedInstanceState);
if(findChildFragment(FirstHomeFragment.class)==null){
// loadRootFragment(R.id.fl_first_container,ZhihuFirstFragment.newInstance());
}
}
}
// fragment_first_home.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:id="@+id/fl_first_container"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:background="@color/bg_app"
android:layout_height="match_parent">
</FrameLayout>
5 创建底部导航的自定义BottomBar
public class BottomBar extends LinearLayout {
}
6 为MainActivity布局中的fl_container加载Fragment
使用loadMultipleRootFragment(…)方法
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SupportFragment firstFragment = findFragment(ZhihuFirstFragment.class);
if (firstFragment == null) {
mFragments[FIRST] = ZhihuFirstFragment.newInstance();
mFragments[SECOND] = ZhihuSecondFragment.newInstance();
mFragments[THIRD] = ZhihuThirdFragment.newInstance();
mFragments[FOURTH] = ZhihuFourthFragment.newInstance();
loadMultipleRootFragment(R.id.fl_container, FIRST,
mFragments[FIRST],
mFragments[SECOND],
mFragments[THIRD],
mFragments[FOURTH]
);
} else {
// 这里库已经做了Fragment恢复,所有不需要额外的处理了, 不会出现重叠问题
// 这里我们需要拿到mFragments的引用
mFragments[FIRST] = firstFragment;
mFragments[SECOND] = findFragment(ZhihuSecondFragment.class);
mFragments[THIRD] = findFragment(ZhihuThirdFragment.class);
mFragments[FOURTH] = findFragment(ZhihuFourthFragment.class);
}
initView();
}
7 为底部BottomBar设置数据关联Fragment
private void initView() {
mBottomBar = (BottomBar) findViewById(R.id.bottomBar);
mBottomBar.addItem(new BottomBarTab(this, R.drawable.ic_home_white_24dp))
.addItem(new BottomBarTab(this, R.drawable.ic_discover_white_24dp))
.addItem(new BottomBarTab(this, R.drawable.ic_message_white_24dp))
.addItem(new BottomBarTab(this, R.drawable.ic_account_circle_white_24dp));
mBottomBar.setOnTabSelectedListener(new BottomBar.OnTabSelectedListener() {
@Override
public void onTabSelected(int position, int prePosition) {
showHideFragment(mFragments[position],mFragments[prePosition]);
}
@Override
public void onTabUnselected(int position) {
}
@Override
public void onTabReselected(int position) {
SupportFragment currentFragment = mFragments[position];
int count = currentFragment.getChildFragmentManager().getBackStackEntryCount();
// 如果不在该类别Fragment的主页,则回到主页;
if(count>1){
if(currentFragment instanceof ZhihuFirstFragment){
currentFragment.popToChild(FirstHomeFragment.class,false);
}else if(currentFragment instanceof ZhihuSecondFragment){
currentFragment.popToChild(ViewPagerFragment.class,false);
}else if(currentFragment instanceof ZhihuThirdFragment){
currentFragment.popToChild(ShopFragment.class,false);
}else if(currentFragment instanceof ZhihuFourthFragment){
currentFragment.popToChild(MeFragment.class,false);
}
return;
}
// 这里推荐使用EventBus来实现 -> 解耦
if(count == 1){
// 在FirstPagerFragment中接收, 因为是嵌套的孙子Fragment 所以用EventBus比较方便
// 主要为了交互: 重选tab 如果列表不在顶部则移动到顶部,如果已经在顶部,则刷新
EventBusActivityScope.getDefault(MainActivity.this).post(new TabSelectedEvent(position));
}
}
});
}
8 为了监听Fragment的返回键,MainActivity需实现OnBackToFirstListener
public class MainActivity extends SupportActivity implements BaseMainFragment.OnBackToFirstListener {
@Override
public void OnBackToFirstFragment() {
// 回到第一个导航页
mBottomBar.setCurrentItem(0);
}
}
