android - 如何在 ViewPager2 页面之间自动切换

Question

<androidx.viewpager2.widget.ViewPager2
        android:id="@+id/view_pager2"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

如何自动移动 ViewPager2 页面？

Answer 1

好的，这是示例...希望您觉得它有帮助

下面我为您提供了片段如何使用 viewpager2 自动更改的示例......

依赖项：

   implementation 'com.google.android.material:material:1.1.0-alpha08'
   implementation 'androidx.viewpager2:viewpager2:1.0.0-beta02'

主要活动

public class MainActivity extends AppCompatActivity {
int ci=0;
java.util.Timer timer;
ViewPager2 myViewPager2;
ViewPagerAdapter myAdapter;
private ArrayList<Fragment> arrayList = new ArrayList<>();

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

    myViewPager2 = findViewById(R.id.view_pager);

    // add Fragments in your ViewPagerFragmentAdapter class
    arrayList.add(new FirstFragment());
    arrayList.add(new SecondFragment());
    arrayList.add(new ThirdFragment());

    myAdapter = new ViewPagerAdapter(getSupportFragmentManager(), getLifecycle());
    // set Orientation in your ViewPager2
    myViewPager2.setOrientation(ViewPager2.ORIENTATION_HORIZONTAL);

    myViewPager2.setAdapter(myAdapter);

    myViewPager2.setPageTransformer(new MarginPageTransformer(1500));
    timer=new Timer();

    timer.schedule(new TimerTask() {
        @Override
        public void run() {
            myViewPager2.post(new Runnable() {
                @Override
                public void run() {

                    Log.d("viewPager",""+ci);
                    myViewPager2.setCurrentItem(ci%7);
                    ci++;

                }
            });
        }
    },1000,3000);//changes 3 second you can change as per requirement
}}

活动主体

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">

<androidx.viewpager2.widget.ViewPager2
    android:id="@+id/view_pager"

    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

这是适配器

public class ViewPagerAdapter extends FragmentStateAdapter {

private ArrayList<Fragment> arrayList = new ArrayList<>();


public ViewPagerAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
    super(fragmentManager, lifecycle);
}

@NonNull
@Override
public Fragment createFragment(int position) {
    switch (position) {
        case 0:
            return new FirstFragment();
        case 1:
            return new SecondFragment();
        case 2:
            return new ThirdFragment();

    }
    return null;
}

@Override
public int getItemCount() {
    return 3;
}}

最后但并非最不重要的一点是，您必须添加诸如 firstFragment、second 等片段...

Answer 2

微小的扩展可以帮助你

fun ViewPager2.enableAutoScroll(totalPages: Int): Timer {
    val autoTimerTask = Timer()
    var currentPageIndex = currentItem
    autoTimerTask.schedule(object : TimerTask() {
        override fun run() {
            currentItem = currentPageIndex++
            if (currentPageIndex == totalPages) {
                autoTimerTask.cancel()
            }
        }
    }, 0, DELAY_FOUR_SECONDS)
    return autoTimerTask
}