确定 ViewPager 何时更改页面 [英] Determine when a ViewPager changes pages

问题描述

我在 ViewPager 中有三个页面(片段)，但是我只想显示其中两个页面的菜单项.

I have three pages (Fragments) inside a ViewPager, however I only want to display a menu item for two of those pages.

以前的 SO 答案 中给出的代码似乎不起作用:

The code given in a previous SO answer does not seem to work:

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);

    if (isVisibleToUser == true) { }
    else if (isVisibleToUser == false) {  }

}

Eclipse 说不需要@Override 并且无法设置 super.它永远不会被系统调用，即使它是我如何确定此刻正在显示哪个页面?我可以在这里帮忙吗?

Eclipse says @Override isn't needed and super can't be set. It's never called by the system, and even if it was how would I determine which page was being shown at the moment? Could I have some help here?

推荐答案

使用ViewPager.onPageChangeListener:

viewPager.addOnPageChangeListener(new OnPageChangeListener() {
    public void onPageScrollStateChanged(int state) {}
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

    public void onPageSelected(int position) {
        // Check if this is the page you want.
    }
});

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