ViewPager当前片段可见性 [英] ViewPager Current Fragment Visibility

问题描述

我有什么

我有一个包含5个片段的ViewPager.每当片段对用户可见时，我都希望对其进行动画处理.

I have a ViewPager with 5 fragments. I want to animate some TextViews inside the fragments whenever they become visible to the user.

我无法使用onResume()，因为左侧和右侧的片段已经创建.我不能使用setUserVisibilityHint()，因为它在onCreateView()之前被调用，因此视图尚未准备就绪.

I can't use onResume() as the fragments to the left and right are already created. I can't use setUserVisibilityHint() as it is called before onCreateView() so the views are not ready yet.

那么，每当用户看到特定片段时，如何为视图设置动画?

So what should be the way to animate the views whenever a particular fragment becomes visible to the user?

推荐答案

我知道这个答案可能会有点晚，但是我希望它可以在类似情况下为他人提供帮助.

I know this answer might be a bit late, but I hope it can help others in a similar situation.

您可以使用 FragmentViewPager 库(我是作者)，该库可以解决您面临的问题为你.其特点是:

You could use FragmentViewPager library (I am the author), which deals with the issue you are facing for you. Its features are:

• 允许其Fragment页在实际出现时得到通知 对用户可见/不可见
• 支持多个级别的FragmentViewPagers(嵌套)
• 提供了控制其分页的方法

• allows its Fragment pages to get notified when they are actually visible/invisible to the user
• supports multiple levels of FragmentViewPagers (nesting)
• provides methods to control its paging

基本用法是:

1. 以编程方式或通过XML将FragmentViewPager附加到活动 或片段，就像使用本机ViewPager
一样
2. 设置FragmentViewPager的适配器.您的适配器应该继承 com.sbrukhanda.fragmentviewpager.adapters.FragmentPagerAdapter或 com.sbrukhanda.fragmentviewpager.adapters.FragmentStatePagerAdapter

3. 覆盖托管活动的onResumeFragments()并调用 FragmentViewPager.notifyPagerVisible():

1. Attach FragmentViewPager programmatically or via XML to an Activity or Fragment, as you would with native ViewPager
2. Set FragmentViewPager's adapter. Your adapter should inherit com.sbrukhanda.fragmentviewpager.adapters.FragmentPagerAdapter or com.sbrukhanda.fragmentviewpager.adapters.FragmentStatePagerAdapter

3. Override onResumeFragments() of the hosting Activity and call FragmentViewPager.notifyPagerVisible():

private FragmentViewPager mFragmentsPager;

@Override 
public void onResumeFragments() {
    super.onResumeFragments();
    mFragmentsPager.notifyPagerVisible();
    ... 
}

主机Fragment的

或onResume()并调用 FragmentViewPager.notifyPagerVisible():

or onResume() of the hosting Fragment and call FragmentViewPager.notifyPagerVisible():

private FragmentViewPager mFragmentsPager;

@Override 
public void onResume() {
    super.onResume();
    mFragmentsPager.notifyPagerVisible();
    ... 
}

覆盖托管活动或片段的onPause()并调用 FragmentViewPager.notifyPagerInvisible():

Override onPause() of the hosting Activity or Fragment and call FragmentViewPager.notifyPagerInvisible():

private FragmentViewPager mFragmentsPager;

@Override 
public void onPause() {
    super.onPause();
    mFragmentsPager.notifyPagerInvisible();
    ... 
}

您在所有Fragment页面上执行的

FragmentVisibilityListener 希望收到有关其可见性状态的回调

您准备好了！

Implement FragmentVisibilityListener on all Fragment pages that you wish to receive callbacks for their visibility state

You are ready to go!

如果您希望看到更完整的示例代码，请检查项目的示例项目.

If you wish to see a more complete sample code, then check project's sample project.

这篇关于ViewPager当前片段可见性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！