onPageSelected调用setCurrentItem时，不触发（0） [英] onPageSelected isn't triggered when calling setCurrentItem(0)

问题描述

我有一个ViewPager它显示了一堆照片的活动。当它启动ViewPager的位置是基于在一个previous活动什么用户选择设定。类似的画廊。

I have an Activity with a ViewPager which displays a bunch of pictures. When it starts the ViewPager's position is set based on what the user selected in a previous Activity. Similar to a gallery.

我希望onPageSelected被称为一个新的页面每次选择，即活动第一次打开时或当用户滑动到一个新的页面。

I want the onPageSelected to be called every time a new page is selected, i.e. when the Activity is first opened or when the user slides to a new page.

我设置的出发点，像这样：

I set the starting point like so:

 mPager.setCurrentItem(index);

一切正常，只是setCurrentItem调用索引设置为0，因为这将不会触发onPageSelected工作。

Everything works, except when setCurrentItem called with index set to 0 as this will not trigger onPageSelected.

mPager.setOnPageChangeListener(new OnPageChangeListener() {
  @Override
  public void onPageSelected(int index) {
    Log.d(TAG, "onPageSelected " + index);
  }
  ...
}

所以我的问题是;这是一个错误，如果是的话我该怎么办呢？

So my question is; is this a bug, and if so what can I do about it?

推荐答案

好了，我一直没能弄清楚这是否是一个错误（或要素）。不过，我想我会分享怎么可能解决这个问题可以看..

Ok, so I haven't been able to figure out whether this is a bug (or a feature). But I thought I'd share how a possible solution to the problem could look..

写你想在活动的方法来执行，然后在功能，称这种现象为onPageSelected方法。

Write the functionality you wish to perform in a method in the Activity and then call this in the onPageSelected method.

mPager.setOnPageChangeListener(new OnPageChangeListener() {
    @Override
    public void onPageSelected(int index) {
        myOnPageSelectedLogic(index);
    }
    ...
}

，然后调用之后

And then right after calling

setCurrentItem(index);

在活动中，添加下面的if语句

in the Activity, add the following if statement

if(index == 0) {
    myOnPageSelectedLogic(0);
}

这不是超pretty的，但我希望它可以帮助别人：）

It's not super pretty but I hope it helps someone :)

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