ViewPager.setOffscreenPageLimit(0) 无法按预期工作 [英] ViewPager.setOffscreenPageLimit(0) doesn't work as expected

问题描述

我在 ViewPager 实例中使用的片段非常耗费资源，所以我只想一次加载一个.当我尝试以下操作时:

The fragments I use in my ViewPager instance are quite resource intensive, so I'd only like to load one at a time. When I try the following:

mViewPager.setOffscreenPageLimit(0);
mViewPager.setAdapter(mPagerAdapter);

我的 FragmentStatePagerAdapter.getItem(int position) 覆盖函数被调用了 3 次，这就是我调用 mViewPager.setOffscreenPageLimit(1) 时发生的情况.我希望它只被调用一次，因为我指定了 0 个屏幕外页面.

My FragmentStatePagerAdapter.getItem(int position) override function is called 3 times, which is what happens when I call mViewPager.setOffscreenPageLimit(1). I would expect it to only be called once, because I specified 0 offscreen pages.

我相信我正确调用了所有内容，因为如果我调用 mViewPager.setOffscreenPageLimit(2)，FragmentStatePagerAdapter.getItem(int position) 会被调用 5 次会期望.

I believe I'm calling everything correctly, because if I call mViewPager.setOffscreenPageLimit(2), FragmentStatePagerAdapter.getItem(int position) is called 5 times as I would expect.

ViewPager 是否需要至少 1 个屏幕外页面，或者我在这里做错了什么?

Does ViewPager require a minimum of 1 offscreen pages, or am I doing something wrong here?

推荐答案

ViewPager 是否需要至少 1 个屏幕外页面

Does ViewPager require a minimum of 1 offscreen pages

是的.如果我正确阅读了源代码，您应该会在 LogCat 中收到关于此的警告，例如:

Yes. If I am reading the source code correctly, you should be getting a warning about this in LogCat, something like:

Requested offscreen page limit 0 too small; defaulting to 1

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