当子ViewPager位于最后一项时，如何防止父ViewPager滚动?

问题描述

我有一个嵌套的ViewPager，可以很好地工作.唯一的问题是，一旦子级ViewPager位于最后一项并且我进一步滚动，父级ViewPager就会滚动.我不要这种行为.

I have a nested ViewPager that works brilliantly. The only issue is, once the child ViewPager is at the last item and I scroll further, the parent ViewPager scrolls. I do not want this behaviour.

我该如何实现?

这里是一个示例，在我的Activity_main.xml中，我有一个父ViewPager，其中包含三个片段页面.

Here is an example, in my Activity_main.xml I have the parent ViewPager, which houses three fragment pages.

 <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

在片段布局之一fragment_categories.xml中，我有另一个ViewPager，它是Activity_main.xml中父viewPager的子代，

Inside one of the fragment layouts, fragment_categories.xml, I have another ViewPager, which is a child to the parent viewPager in the Activity_main.xml,

<android.support.v4.view.ViewPager
    android:id="@+id/mViewPager"
    android:layout_width="match_parent"
    android:layout_height="@dimen/offer_height"
    android:layout_marginTop="2dp"
    android:overScrollMode="never"/>

一切正常.但是，当子级viewPager到达其最后一项，并且我滚动得更多时，父级viewPager将移至下一页.我不想这样.我尝试通过拦截父ViewPager上的触摸来做到这一点，但这没有用.我猜我做错了吗? (是的，我将xml中的标签更改为com.project.CustomViewPager并尝试了此操作.)

It all works fine. But when the child viewPager reaches its last item, and I scroll more, the parent viewPager moves to the next page. I do not want this. I tried doing this by intercepting touch on the parent ViewPager before, and that didn't work. I'm guessing I'm doing it wrong? (Yes, I changed tags in the xml to com.project.CustomViewPager and tried this.)

CustomViewPager.java:

  public CustomViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
        if(v != this && v instanceof ViewPager) {
            return false;
        }

        return super.canScroll(v, checkV, dx, x, y);
    }

推荐答案

首先创建一个CustomViewPager来更改其可滑动状态，如下所示:

First create a CustomViewPager to change it's swipeable state like below:

public class CustomViewPager extends ViewPager {
    private boolean canScroll = true;
    public CustomViewPager(Context context) {
        super(context);
    }
    public CustomViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public void setCanScroll(boolean canScroll) {
        this.canScroll = canScroll;
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return canScroll && super.onTouchEvent(ev);
    }
    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return canScroll && super.onInterceptTouchEvent(ev);
    }

    public boolean isCanScroll() {
        return canScroll;
    }
}

第二次更改要禁用的视图寻呼机，将其滑动到CustomViewPager

Second change your view pager which you want to disable it's swipe propery to your CustomViewPager

获取您的查看传呼机:

CustomViewPager myCustomViewPager = (CustomViewPager) findViewById(R.id.my_custom_pager);
ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);

在您的ViewPager中添加onTouchListener:

Add an onTouchListener to your ViewPager:

viewPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction())
                {
                    case MotionEvent.ACTION_DOWN:
                        myCustomViewPager.setCanScroll(false);
                        break;

                    case MotionEvent.ACTION_UP:
                        myCustomViewPager.setCanScroll(true);
                        break;
                }
                return false;
            }
        });

如果您真的需要检查您的Viewpager当前位置:

If you really need to check if your viewpager's current position:

    int pos = 0;
    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                @Override
                public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

                }

                @Override
                public void onPageSelected(int position) {
                   pos = position;
                }

                @Override
                public void onPageScrollStateChanged(int state) {

                }
            });

然后您可以查看MotionEvents if pos == yourAdaptersItemCount-1并禁用或启用customViewPager.

And you can chek in your MotionEvents if pos == yourAdaptersItemCount-1 and disable or enable your customViewPager.

祝你好运.

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