android - 从 ViewPager 获取当前 View

Question

我正在尝试使用 Viewpager.findViewWithTag 从 ViewPager 获取当前页面 View 。当尝试从 ViewPager 获取当前 View 时，它返回 Null；

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.viewpager_main);
    Bundle bundle = getIntent().getExtras();
    chapter = bundle.getInt("chapter");


    ViewPagerAdapter adapter = new ViewPagerAdapter(this, chapter);
    pager = (ViewPager) findViewById(R.id.pager);
    pager.setAdapter(adapter);

    View myView = pager.findViewWithTag(pager.getCurrentItem());

...这是我的 ViewPageAdapter

 @Override
public Object instantiateItem(ViewGroup container, int position) {
    LayoutInflater inflater;
    if(position != 10){
            inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     itemView = inflater.inflate(R.layout.viewpager_item, container,
            false);
      itemView.setTag(position);

    } else {
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         itemView = inflater.inflate(R.layout.results, container,
                false);
    }
    container.addView(itemView);
    return itemView ;
}

这里是viewpager_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<android.support.v4.view.ViewPager
    android:id="@+id/pager"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />
</RelativeLayout>

这里是 viewpager_item.xml

<?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:orientation="vertical" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="300dp"
    android:gravity="center_horizontal" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:background="#fff"
        android:scaleType="fitCenter"
        />
</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:gravity="center_horizontal">

    <Button
        android:id="@+id/Button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tag="1"
        android:text="1" />

    <Button
        android:id="@+id/Button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tag="2"
        android:text="2" />

    <Button
        android:id="@+id/Button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tag="3"
        android:text="3" />

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal" >

    <Button
        android:id="@+id/Button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tag="4"
        android:text="4" />

    <Button
        android:id="@+id/Button5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tag="5"
        android:text="5" />
</LinearLayout>

我不知道我哪里做错了，但无法修复。谢谢

Answer 1

你可以试试这样的——

@Override
public Object instantiateItem(ViewGroup container, int position) {
    LayoutInflater inflater;
    if(position != 10){
            inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     itemView = inflater.inflate(R.layout.viewpager_item, container,
            false);
      itemView.setTag("View"+position);

    } else {
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         itemView = inflater.inflate(R.layout.results, container,
                false);
    }
    container.addView(itemView);
    return itemView ;
}

当您需要当前 View 时-

View myView = pager.findViewWithTag("View"+pager.getCurrentItem());