我想使用Android设计支持库来实现以下UI:
以下代码初始化了
以下代码会随机初始化
- 带有
NavigationView
用于部分导航的Activity。 - 选择某个部分后,将会把新的(父级)
Fragment
替换为容器空间中的FrameLayout
。 - (父级)
Fragment
始终是一个CoordinatorLayout
。在布局中,可以使用ViewPager
。(*问题) - 如果使用
ViewPager
作为(父级)Fragment
,它几乎总是伴随着多个带有RecyclerView
的子级Fragment
。(*问题)
问题
- 在
ViewPager
上滑动时,它无法正确地滑动(例如,不是每次滑动1页)。 没有显示RecyclerView
项(根本没有显示)。
Activity布局
在Activity
中,有一个带有NavigationView
和一个用于固定内容的FrameLayout
的DrawerLayout
,如下所示:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<FrameLayout
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true" />
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_main"
app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
片段交换
每当选择一个导航项(部分)时,以下代码将新的(父级)片段与FrameLayout (R.id.container)
进行交换:
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.container, new ParentFragment())
.commit();
父片段(ViewPager)
在父片段中,CoordinatorLayout
与 AppBarLayout
和 ViewPager
结合使用,如下所示:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.test.nestedviewpager.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
<android.support.design.widget.TabLayout
android:id="@+id/tab_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true" />
</android.support.design.widget.CoordinatorLayout>
以下代码初始化了
ParentFragment
,带有随机数量的页面。package com.test.nestedviewpager;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
public class ParentFragment extends Fragment {
private static final int MAX_PAGE_COUNT = 5;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_parent, container, false);
AppCompatActivity activity = (AppCompatActivity) getActivity();
activity.setSupportActionBar((Toolbar) root.findViewById(R.id.toolbar));
final ActionBar actionBar = activity.getSupportActionBar();
if (actionBar != null) {
actionBar.setHomeAsUpIndicator(R.drawable.ic_menu);
actionBar.setDisplayHomeAsUpEnabled(true);
}
ViewPager viewPager = (ViewPager) root.findViewById(R.id.view_pager);
viewPager.setAdapter(new MyPagerAdapter(activity.getSupportFragmentManager(), generatePages()));
TabLayout tabLayout = (TabLayout) root.findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(viewPager, true);
return root;
}
private static Page[] generatePages() {
Random rng = new Random();
int size = rng.nextInt(MAX_PAGE_COUNT);
if (size <=0 ) { size = 1; }
Page[] pages = new Page[size];
for (int pos = 0; pos < size; pos++) {
pages[pos] = new Page("Page " + (pos + 1));
}
return pages;
}
private static class MyPagerAdapter extends FragmentPagerAdapter {
private final List<Page> mPageList = new ArrayList<>();
MyPagerAdapter(FragmentManager fm, Page[] pages) {
super(fm);
if ((pages != null) && (pages.length > 0)) {
mPageList.addAll(Arrays.asList(pages));
}
}
@Override
public int getCount() {
return mPageList.size();
}
@Override
public Fragment getItem(int position) {
return new ChildFragment();
}
@Override
public CharSequence getPageTitle(int position) {
return mPageList.get(position).title;
}
}
private static class Page {
final String title;
Page(String title) {
this.title = title;
}
}
}
子片段(RecyclerView)
在每个子片段中,包含一个如下所示的RecyclerView
:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
以下代码会随机初始化
ChildFragment
中的项数。package com.test.nestedviewpager;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;
public class ChildFragment extends Fragment {
private static final int MAX_ITEM_COUNT = 15;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_child, container, false);
RecyclerView recyclerView = (RecyclerView) root.findViewById(R.id.recycler_view);
recyclerView.setAdapter(new MyRecyclerAdapter(generateItems()));
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
return root;
}
private static Item[] generateItems() {
Random rng = new Random();
final int size = rng.nextInt(MAX_ITEM_COUNT);
if (size > 0) {
Item[] items = new Item[size];
for (int pos = 0; pos < size; pos++) {
items[pos] = new Item("Item " + (pos + 1));
}
return items;
}
return null;
}
private static class MyRecyclerAdapter extends RecyclerView.Adapter<MyRecyclerAdapter.MyViewHolder> {
private final List<Item> mItemList = new ArrayList<>();
MyRecyclerAdapter(Item[] items) {
if ((items != null) && (items.length > 0)) {
mItemList.addAll(Arrays.asList(items));
}
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View itemView = inflater.inflate(R.layout.recycler_item, parent, false);
return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.bind(mItemList.get(position));
}
@Override
public int getItemCount() {
return mItemList.size();
}
static class MyViewHolder extends RecyclerView.ViewHolder {
private TextView mTitleView;
MyViewHolder(View itemView) {
super(itemView);
mTitleView = (TextView) itemView.findViewById(R.id.content);
}
void bind(Item item) {
mTitleView.setText(item.title);
}
}
}
private static class Item {
final String title;
Item(String title) {
this.title = title;
}
}
}
我完全不理解代码有什么问题。非常感谢任何帮助。
谢谢。
Fragment
完全控制屏幕,因此在那里有一个FrameLayout
和(父)Fragment
中的CoordinatorLayout
,在运行时进行交换。我不能把CoordinatorLayout
放在Fragment
中吗? - LightYearsBehind