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Android中ViewPager1和ViewPager2的使用教程

2024-04-02 19:55

短信预约 -IT技能 免费直播动态提醒

Android X的东西都已经使用很久了，都没好好记录一下，

现在记录一下Android X 下 ViewPager1和ViewPager2的使用，几乎是每个项目中都会使用的控件，他们之间还是有点区别的，

案例效果图，ViewPager和ViewPager2

首先ViewPager1和ViewPager2 是在Android X 的appcompat 库中，创建项目就有的

xml


     <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
 
     <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewpager2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

首页来看看ViewPager1的Adapter


public class MyFragmentPagerAdapter extends FragmentPagerAdapter {
       
        private List<Fragment> fragmentList;
 
        public MyFragmentPagerAdapter(FragmentManager fm,List<Fragment> fragmentList) {
            super(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
            this.fragmentList = fragmentList;
        }
 
        @NonNull
        @Override
        public Fragment getItem(int position) {
            return fragmentList.get(position);
        }
 
        @Override
        public int getCount() {
            return fragmentList.size();
        }
    }

ViewPager2的Adapter


public class MyFragmentPagerAdapter extends FragmentStateAdapter {
 
        private List<Fragment> fragmentList;
 
        public MyFragmentPagerAdapter(@NonNull @NotNull FragmentActivity fragmentActivity,List<Fragment> fragmentList) {
            super(fragmentActivity);
            this.fragmentList = fragmentList;
        }
        @NonNull
        @NotNull
        @Override
        public Fragment createFragment(int i) {
            return fragmentList.get(i);
        }
 
        @Override
        public int getItemCount() {
            return fragmentList.size();
        }
    }

ViewPager加载Fragment


MyFragmentPagerAdapter pagerAdapter = new MyFragmentPagerAdapter(getSupportFragmentManager(),fragmentList);
        viewpager.setAdapter(pagerAdapter);
        viewpager.setOffscreenPageLimit(fragmentList.size());
        viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            }
 
            @Override
            public void onPageSelected(int position) {//滑动到第几个
                navigation.getMenu().getItem(position).setChecked(true);
            }
 
            @Override
            public void onPageScrollStateChanged(int state) {
            }
        });

ViewPager2加载Fragment


MyFragmentPagerAdapter pagerAdapter = new MyFragmentPagerAdapter(this,fragmentList);
        viewpager2.setAdapter(pagerAdapter);
        viewpager2.setOffscreenPageLimit(fragmentList.size());
        viewpager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                super.onPageScrolled(position, positionOffset, positionOffsetPixels);
            }
 
            @Override
            public void onPageSelected(int position) {//滑动到第几个
                super.onPageSelected(position);
                navigation.getMenu().getItem(position).setChecked(true);
            }
 
            @Override
            public void onPageScrollStateChanged(int state) {
                super.onPageScrollStateChanged(state);
            }
        });

效果图是结合BottomNavigationView+ViewPager一起使用的

上一篇博客讲到了BottomNavigationView，可以去看看他的介绍

BottomNavigationView+ViewPager/ViewPager2的绑定都是一样的


 navigation.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull @NotNull MenuItem menuItem) {
                if (menuItem.getItemId() == R.id.menu_mail){
                    viewpager.setCurrentItem(0);
                }else if (menuItem.getItemId() == R.id.menu_bookshelf){
                    viewpager.setCurrentItem(1);
                }else if (menuItem.getItemId() == R.id.menu_my_config){
                    viewpager.setCurrentItem(2);
                }
                return false;
            }
        });

还有一种方式：


navigation.setOnNavigationItemSelectedListener(item -> {
           Toast.makeText(ApiDemo1Activity2.this,
                   "下标"+item.getOrder(),Toast.LENGTH_LONG).show();
            viewpager.setCurrentItem(item.getOrder());
            return true;
        });

这个下标如何来的呢？

那当然是BottomNavigationView 绑定的按钮中设置的了


<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    tools:showIn="bottom_navigation_view">
 
    <item
        android:id="@+id/menu_mail"
        android:icon="@drawable/ic_bottom_mail"
        android:title="@string/book_mail"
        android:orderInCategory="0"
        />
 
    <item
        android:id="@+id/menu_bookshelf"
        android:icon="@drawable/ic_bottom_books"
        android:orderInCategory="1"
        android:title="@string/book_shelf" />
 
    <item
        android:id="@+id/menu_my_config"
        android:icon="@drawable/ic_bottom_person"
        android:orderInCategory="2"
        android:title="@string/my" />
 
</menu>

属性 android:orderInCategory="0" 来设置下标，这样就更方便绑定ViewPager了

总结ViewPager和ViewPager2的区别