Viewpager2—登录注册引导页面

Viewpager2

- 介绍
- 例子
- 总结

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介绍

屏幕滑动是两个完整屏幕之间的切换，在设置向导或幻灯片等界面中很常见

实现图(图片来源于网络):

例子

1、创建视图
我这里只创建了3个XML

fragment0.xml

<?xml version="1.0" encoding="utf-8"?>    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:id="@+id/content"        android:layout_width="match_parent"        android:layout_height="match_parent" >    <ImageView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:adjustViewBounds="true"        android:scaleType="fitXY"        android:src="@drawable/p0"        />    </LinearLayout>

fragment1.xml

<?xml version="1.0" encoding="utf-8"?>    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:id="@+id/content"        android:layout_width="match_parent"        android:layout_height="match_parent" >    <ImageView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:adjustViewBounds="true"        android:scaleType="fitXY"        android:src="@drawable/p1"        />    </LinearLayout>

fragment2.xml

<?xml version="1.0" encoding="utf-8"?>    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:id="@+id/content"        android:layout_width="match_parent"        android:layout_height="match_parent" >    <ImageView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:adjustViewBounds="true"        android:scaleType="fitXY"        android:src="@drawable/p2"        />    </LinearLayout>

2、创建 Fragment
根据构造方法传进来的 int i；返回不同的视图(i是等下用到的FragmentStateAdapter适配器中传进去的)

package com.example.xianyu;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import androidx.annotation.NonNull;import androidx.annotation.Nullable;import androidx.fragment.app.Fragment;public class mFragment extends Fragment {         int i = 0;    mFragment(int i){             this.i = i;    }        @Nullable    @Override    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {             View view = null;        switch (i){                 case 0: {                 view = inflater.inflate(R.layout.fragment0, container, false);            break;       }            case 1: {                 view =  inflater.inflate(R.layout.frament1, container, false);            break;        }            case 2: {                     view = inflater.inflate(R.layout.fragment2, container, false);                break;            }        }        return view;    }}

3、主Activity，并创建自定义适配器继承自FragmentStateAdapter

activity_screen_slide.xml

<?xml version="1.0" encoding="utf-8"?><!-- activity_screen_slide.xml --><androidx.viewpager2.widget.ViewPager2    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/pager"    android:layout_width="match_parent"    android:layout_height="match_parent" />

homeActivity

package com.example.xianyu;import android.os.Bundle;import androidx.fragment.app.Fragment;import androidx.fragment.app.FragmentActivity;import androidx.viewpager2.adapter.FragmentStateAdapter;import androidx.viewpager2.widget.ViewPager2;public class homeActivity extends FragmentActivity {         //要显示的页数    private static final int NUM_PAGES = 3;    private ViewPager2 viewPager2;     // 适配器，为ViewPager2提供页面     private FragmentStateAdapter pagerAdapter;        @Override    protected void onCreate(Bundle savedInstanceState) {             super.onCreate(savedInstanceState);        setContentView(R.layout.activity_screen_slide);        viewPager2 = findViewById(R.id.pager);        pagerAdapter = new ScreenSlidePagerAdapter(this);        viewPager2.setAdapter(pagerAdapter);    }    @Override    public void onBackPressed() {             if (viewPager2.getCurrentItem() == 0) {                             super.onBackPressed();        } else {                            viewPager2.setCurrentItem(viewPager2.getCurrentItem() - 1);        }    } //自定义的类，继承自FragmentStateAdapter适配器    private class ScreenSlidePagerAdapter extends FragmentStateAdapter {             public ScreenSlidePagerAdapter(FragmentActivity fa) {                 super(fa);        }//主要是createFragment这个方法        @Override        public Fragment createFragment(int position) {                 return new mFragment(position);        }        @Override        public int getItemCount() {                 return NUM_PAGES;        }    }}

总结

非常实用，快快收藏叭！

Viewpager2

介绍

例子

总结

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