【笔记】Android控件ViewPage

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前言

Android控件ViewPage学习笔记
有点像轮播图效果

创建多个布局

/app/src/main/res/layout/layout1.xml

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<?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:background="#FF0000">

</LinearLayout>

/app/src/main/res/layout/layout2.xml

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<?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:background="#00FF00">

</LinearLayout>

/app/src/main/res/layout/layout3.xml

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<?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:background="#0000FF">

</LinearLayout>

创建构造器

/app/src/main/java/…/MyAdapter.java

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public class MyAdapter extends PagerAdapter {

    private List<View> viewList;

    public MyAdapter(List<View> viewList) {
        this.viewList = viewList;
    }

    // 布局个数
    @Override
    public int getCount() {
        return viewList.size();
    }

    // 将指定位置的布局添加到ViewGroup中，返回key值
    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        container.addView(this.viewList.get(position), 0);
        return this.viewList.get(position);
    }

    // 通过key值，判断两个页面是否相同
    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
        return view == object;
    }

    // 销毁指定位置的布局
    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView(this.viewList.get(position));
    }
}public class MyAdapter extends PagerAdapter {

    private List<View> viewList;

    public MyAdapter(List<View> viewList) {
        this.viewList = viewList;
    }

    // 布局个数
    @Override
    public int getCount() {
        return viewList.size();
    }

    // 将指定位置的布局添加到ViewGroup中，返回key值
    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        container.addView(this.viewList.get(position), 0);
        return this.viewList.get(position);
    }

    // 通过key值，判断两个页面是否相同
    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
        return view == object;
    }

    // 销毁指定位置的布局
    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView(this.viewList.get(position));
    }
}

通过构造器将布局渲染页面

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// 获取布局对象
View view1 = getLayoutInflater().inflate(R.layout.layout1, null);
View view2 = getLayoutInflater().inflate(R.layout.layout2, null);
View view3 = getLayoutInflater().inflate(R.layout.layout3, null);

// 添加所有布局到集合
List<View> viewList = new ArrayList<>();
viewList.add(view1);
viewList.add(view2);
viewList.add(view3);

// 利用布局集合创建一个构造器
MyAdapter myAdapter = new MyAdapter(viewList);

// 设置构造器
ViewPager viewPager = findViewById(R.id.vp);
viewPager.setAdapter(myAdapter);

完成

参考文献

哔哩哔哩——Android架构解析