ViewPager中嵌套ViewPager
在現(xiàn)在很多的應(yīng)用程序中都會用到ViewPager嵌套ViewPager的情況，比如掌上英雄聯(lián)盟。
如圖，下面的四個(gè)按鈕是控制一個(gè)ViewPager，在使用到ViewPager嵌套ViewPager的時(shí)候，外層的ViewPager必須設(shè)置不能滑動，以免造成兩個(gè)ViewPager產(chǎn)生沖突，在這里的第一個(gè)Fragment中也用到了一個(gè)ViewPager，并結(jié)合TabLayout實(shí)現(xiàn)一個(gè)ViewPager的使用。我們來詳細(xì)介紹這一個(gè)Fragment中的ViewPager。
Fragment的布局文件
<?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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="@+id/com_tablayout"
android:layout_width="match_parent"
android:layout_height="50dp"
app:tabIndicatorHeight="0dp"
app:tabMode="fixed"
app:tabGravity="fill"
app:tabSelectedTextColor="#ffaa00"
app:tabTextColor="#000"
></android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="@+id/com_viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"></android.support.v4.view.ViewPager>
</LinearLayout>
tabIndicatorHeight是設(shè)置TabLayout下的標(biāo)志線的大小，在設(shè)置為0dp，是為了隱藏標(biāo)志線。tabMode是設(shè)置tablayout是固定或是滑動的，fixed為固定，scrollable為可以滑動。app:tabGravity="fill"設(shè)置布滿。tabSelectedTextColor設(shè)置tab選中文字的顏色，tabTextColor設(shè)置tab為選中的顏色。
Fragment的Java文件
package com.william.william.html.Fragment;
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.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.william.william.html.R;
/**
* Created by william on 2017/4/2.
*/
public class ComFragment extends Fragment {
private TabLayout mTablayout;
private ViewPager mViewPager;
private TabLayout.Tab video;
private TabLayout.Tab news;
private TabLayout.Tab smart;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = LayoutInflater.from(getContext()).inflate(R.layout.fragment_community, container, false);
mTablayout = (TabLayout) view.findViewById(R.id.com_tablayout);
mViewPager = (ViewPager) view.findViewById(R.id.com_viewpager);
mViewPager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager()) {
private String[] mTitles = new String[]{"視頻", "新聞", "智能硬件"};
@Override
public Fragment getItem(int position) {
if (position == 0) {
return new VideoFragment();
} else if (position == 1) {
return new NewsFragment();
} else
return new SmartFragment();
}
@Override
public int getCount() {
return mTitles.length;
}
@Override
public CharSequence getPageTitle(int position) {
return mTitles[position];
}
});
mTablayout.setupWithViewPager(mViewPager);
video = mTablayout.getTabAt(0);
news = mTablayout.getTabAt(1);
smart = mTablayout.getTabAt(2);
video.setIcon(getResources().getDrawable(R.drawable.tab_select_icon));
news.setIcon(getResources().getDrawable(R.drawable.tab_unselect_icon));
smart.setIcon(getResources().getDrawable(R.drawable.tab_unselect_icon));
mTablayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
if (tab == video) {
video.setIcon(getResources().getDrawable(R.drawable.tab_select_icon));
mViewPager.setCurrentItem(0);
} else if (tab == news) {
news.setIcon(getResources().getDrawable(R.drawable.tab_select_icon));
mViewPager.setCurrentItem(1);
} else {
smart.setIcon(getResources().getDrawable(R.drawable.tab_select_icon));
mViewPager.setCurrentItem(2);
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
if (tab == video) {
video.setIcon(getResources().getDrawable(R.drawable.tab_unselect_icon));
} else if (tab == news) {
news.setIcon(getResources().getDrawable(R.drawable.tab_unselect_icon));
} else {
smart.setIcon(getResources().getDrawable(R.drawable.tab_unselect_icon));
}
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
System.out.println(position);
switch (position) {
case 0:
video.select();
break;
case 1:
news.select();
break;
case 2:
smart.select();
break;
default:
break;
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
return view;
}
}
為ViewPager設(shè)置適配器，ViewPager設(shè)置的是FragmentPagerAdapter，并重寫getItem(),getCount(),getPageTitle()這三個(gè)方法。mTablayout.setupWithViewPager(mViewPager);將tablayout與viewpager關(guān)聯(lián)在一起。
為tablayout設(shè)置OnTabSelectedListener和為viewpager設(shè)置OnPageChangeListener。
在這里要特別說明的是mViewPager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager()) 中需要用到的是getChildFragmentManager()，而不是getSupportFragmentManager。
設(shè)置為getSupportFragmentManager()的時(shí)候，在外面的viewpager滑動后里面的viewpager就顯示不了。
