Question

我希望能够在用户尝试滑动到ViewPager中的下一页时验证该页面并使用canSlideOut弹出错误消息。

两个问题：

每次滑动多次调用canSlideOut
我在页面内有一个带有EditTexts的ListView。不想拦截对他们有意义的事件。

代码：

public class StudentPager extends ViewPager {
    PagerActivity mPagerActivity;

    public StudentPager(Context context) {
        super(context);
    }

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

    public void setPagerActivity(PagerActivity pagerActivity) {
        mPagerActivity = pagerActivity;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return mPagerActivity.canSlideOut() && super.onTouchEvent(event);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        return mPagerActivity.canSlideOut() && super.onInterceptTouchEvent(event);
    }
}

Answer 1

此代码有效，不是很优雅。当canSlideOut返回false时，它会让页面稍微蠕动，我无法找到防止它的方法。

public class StudentPager extends ViewPager {
    PagerActivity mPagerActivity;
    private boolean mIntercepted;
    private boolean mBlockSlideOut;

    public StudentPager(Context context) {
        super(context);
    }

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

    public void setPagerActivity(PagerActivity pagerActivity) {
        mPagerActivity = pagerActivity;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return !mBlockSlideOut && super.onTouchEvent(event);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        // The purpose of all this is just to enable blocking of a SlideOut
        // via the canSlideOut() call.  This isn't quite perfect, because it lets
        // the page creep a little, but so far I haven't found a better solution

        final int action = event.getAction() & MotionEvent.ACTION_MASK;
        if (action == MotionEvent.ACTION_DOWN || action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
            // This swipe is complete, reset flags
            mIntercepted = false;
            mBlockSlideOut = false;
        }

        if (mBlockSlideOut) {
            return false;
        }

        if (!mIntercepted) {
            mBlockSlideOut = false;
            mIntercepted = super.onInterceptTouchEvent(event);
            if (mIntercepted && !mBlockSlideOut) {
                // Here's the opportunity to block the slideout.
                // Making sure that this gets called only once per swipe,
                // because the callback can display a message
                mBlockSlideOut = !mPagerActivity.canSlideOut();
            }
            return mIntercepted && !mBlockSlideOut;
        }

        return super.onInterceptTouchEvent(event);
    }
}

使用验证/错误消息拦截ViewPager滚动

1 个答案: