Android—引导页

activity.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".MainActivity">

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></android.support.v4.view.ViewPager>

</android.support.constraint.ConstraintLayout>

在创建三个引导页面，guide_one，guide_two，guide_three：
guide_one.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/ic_shenone">
    
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="一"
        android:textSize="60dp"
        android:layout_centerInParent="true"
        android:textColor="#03fa72"/>

</RelativeLayout>

guide_two和one时一样的，只是导入图片不同而已，重点在第三个 guide_three

gudie_three.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/ic_shenthree">

    <Button
        android:id="@+id/btn_queding"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="立即体验"
        android:textSize="50dp"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="60dp"
        android:background="#07e4f4"
        android:textColor="#ffffff"/>

</RelativeLayout>

activity_guide.xml：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".GuideActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Hello World!"
        android:textSize="30dp"/>

</RelativeLayout>

GuideActivity.java 不变，我这里就不列举了！

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private ViewPager viewPager;
    private View viewOne,viewTwo,viewThree; //  三个滑动界面对应三个 view 对象
    private ArrayList<View> viewArrayList = null;
    private MyPagerAdapter adapter = null;
    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = findViewById(R.id.viewpager);

        /** 获取三个布局文件，生成 View 对象**/
        LayoutInflater inflater = getLayoutInflater();
        viewOne = inflater.inflate(R.layout.guide_one,null);
        viewTwo = inflater.inflate(R.layout.guide_two,null);
        viewThree = inflater.inflate(R.layout.guide_three,null);
        viewArrayList = new ArrayList<>();
        viewArrayList.add(viewOne);     //  构建显示组件列表
        viewArrayList.add(viewTwo);
        viewArrayList.add(viewThree);
        adapter = new MyPagerAdapter(viewArrayList);
        viewPager.setAdapter(adapter);  //添加适配器

        button = viewThree.findViewById(R.id.btn_queding);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,GuideActivity.class);
                startActivity(intent);
                MainActivity.this.finish();
            }
        });
    }
}

MyPagerAdapter.java

public class MyPagerAdapter extends PagerAdapter {
    private ArrayList<View> pageList=null;  //  接收构造方法中传来的 view 列表

    public MyPagerAdapter(ArrayList<View> pageList) {
        this.pageList = pageList;
    }

    @Override
    public int getCount() {
        return pageList.size(); //  返回 view 列表的大小，即 view 的数目
    }

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
        return view == o;
    }

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        View pageView = pageList.get(position); // 获取当前位置的 view
        container.addView(pageView);    //  设置当前 view 为显示对象
        return pageView;
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView(pageList.get(position));       //  移除当前位置的 view
    }
}