判断SwipeRefreshLayout的childView是否到达顶部

最新推荐文章于 2021-04-25 15:15:37 发布

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本文介绍了一种定制化的SwipeRefreshLayout组件——MySwipeRefreshLayout。该组件确保只有当子视图到达顶部时才能进行下拉刷新操作。通过重写canChildScrollUp方法并针对不同Android版本做了兼容处理，实现了这一功能。

重写swipRefreshLayout，实现chidView只有到达顶部的时候，才可以下拉刷新：
使用方法：直接在xml中使用MySwipeRefreshLayout


import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.SwipeRefreshLayout;
import android.util.AttributeSet;
import android.view.View;
import android.widget.AbsListView;

/**
 * Created by Jack on 2017/7/12.
 */

public class MySwipeRefreshLayout extends SwipeRefreshLayout{
    //实际需要滑动的child view
    private View mScrollUpChild;

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

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

    public void setScrollUpChild(View view) {
        mScrollUpChild = view;
    }


    @Override
    public boolean canChildScrollUp() {
        if (mScrollUpChild != null) {
            if (android.os.Build.VERSION.SDK_INT < 14) {
                if (mScrollUpChild instanceof AbsListView) {
                    final AbsListView absListView = (AbsListView) mScrollUpChild;
                    return absListView.getChildCount() > 0
                            && (absListView.getFirstVisiblePosition() > 0 || absListView.getChildAt(0)
                            .getTop() < absListView.getPaddingTop());
                } else {
                    return ViewCompat.canScrollVertically(mScrollUpChild, -1) || mScrollUpChild.getScrollY() > 0;
                }
            } else {
                return ViewCompat.canScrollVertically(mScrollUpChild, -1);
            }
        }
        return super.canChildScrollUp();
    }


}