配合SmartRefreshLayout使用会有回弹闪动现象

[Jiang00]

https://github.com/scwang90/SmartRefreshLayout

NestedScrollAgentWebView重新写了onTouchEvent方法解决了这个问题却又引发了另一个问题，webview还没滑到顶部就把SmartRefreshLayout的头给滑出来了

[xiexindev]

我的下拉刷新也遇到过类似的问题. 我是用了一个状态类去处理的

• 状态管理类

private static final class RefreshEnableState extends MutableLiveData<RefreshEnableState> {

        private static final int FLAG_WEB_VIEW_SCROLL = 0x1; // WebView滑动锁
        private static final int FLAG_WEB_VIEW_TITLE = 0x2; // 特定标题锁
        private static final int FLAG_ACTION_BAR = 0x4; //ActionBar锁
        private int mLockFlag = 0;

        private void updateWebViewScrollState(boolean release) {
            updateValue(release, FLAG_WEB_VIEW_SCROLL);
        }

        private void updateWebViewTitleState(boolean release) {
            updateValue(release, FLAG_WEB_VIEW_TITLE);
        }

        private void updateActionBarState(boolean release) {
            updateValue(release, FLAG_ACTION_BAR);
        }

        private boolean isEnabled() {
            return mLockFlag == 0; //所有的锁都释放了才允许滑动
        }

        private void updateValue(boolean release, int flag) {
            final int before = mLockFlag;
            if (release) {
                mLockFlag &= ~flag;
            } else {
                mLockFlag |= flag;
            }
            if (mLockFlag != before) postValue(this); //更新锁状态
        }
    }

• WebView滑动监听

NestedScrollAgentWebView webView = new NestedScrollAgentWebView(this) {
            @Override
            protected void onScrollChanged(int l, int t, int oldl, int oldt) {
                //判断WebView是否滑到顶
                mRefreshEnableState.updateWebViewScrollState(getScrollY() == 0);
                super.onScrollChanged(l, t, oldl, oldt);
            }
        };

• 特定Title监听(WebChromeClient#onReceivedTitle 回调)

private void updateWebViewTitleState(String title) {
        mRefreshEnableState.updateWebViewTitleState(!(
                title.equalsIgnoreCase(WebConstants.NOT_SUPPORT_TITLE_ERROR)
                        || title.equalsIgnoreCase(WebConstants.DOWNLOADING_TITLE)
        ));
    }

• ActionBar完全显示监听

((AppBarLayout) findViewById(R.id.appBarLayout))
                .addOnOffsetChangedListener((appBarLayout, verticalOffset) ->
                        mRefreshEnableState.updateActionBarState(verticalOffset == 0));

• 注册LiveData监听

 mRefreshEnableState.observe(this, state -> refreshLayout.setEnabled(state.isEnabled()));

总之, 你想添加多少控制就在状态管理里面处理多少控制就行.

[Jiang00]

@xiexindev 感谢，我用其他方法解决了，暂时没发现其他问题。

• 修改了NestedScrollAgentWebView的onTouchEvent方法

  @Override public boolean onTouchEvent(MotionEvent event) {

    final MotionEvent trackEvent = MotionEvent.obtain(event);
    final int action = event.getActionMasked();
  
    if (action == MotionEvent.ACTION_DOWN) {
        mNestedOffsetY = 0;
    }
  
    final int eventY = (int) trackEvent.getY();
    trackEvent.offsetLocation(0, mNestedOffsetY);
  
    switch (action) {
        case MotionEvent.ACTION_MOVE:
            int deltaY = mLastY - eventY;
  
            if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) {
                deltaY -= mScrollConsumed[1];
                trackEvent.offsetLocation(0, -mScrollOffset[1]);
                mNestedOffsetY += mScrollOffset[1];
            }
  
            mLastY = eventY - mScrollOffset[1];
  
            int oldY = getScrollY();
            int newScrollY = Math.max(0, oldY + deltaY);
            int dyConsumed = newScrollY - oldY;
            int dyUnconsumed = deltaY - dyConsumed;
  
  
            if (dispatchNestedScroll(0, mScrollOffset[1], 0, dyUnconsumed, mScrollOffset)) {
                mLastY -= mScrollOffset[1];
                trackEvent.offsetLocation(0, mScrollOffset[1]);
                mNestedOffsetY += mScrollOffset[1];
            }
            break;
  
        case MotionEvent.ACTION_DOWN:
            mLastY = eventY;
            startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
            break;
        case MotionEvent.ACTION_POINTER_DOWN:
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
            stopNestedScroll();
            break;
  
        default:
            // We don't care about other touch events
    }
  
    // Execute event handler from parent class in all cases
    boolean eventHandled = super.onTouchEvent(trackEvent);
  
    // Recycle previously obtained event
    trackEvent.recycle();
  
    return eventHandled;
  

  }