监听WebView的Scroll滑动效果——下滑隐藏actionBar,下滑显示actionBar

短命女 2022-07-12 05:18 280阅读 0赞

一：自定义WebView，添加回调的监听器

package app.coolwhether.com.zhihudailynews.support;
    
    import android.content.Context;
    import android.util.AttributeSet;
    import android.util.Log;
    import android.view.View;
    import android.webkit.WebView;
    
    /** * Created by kirito on 2017.02.12. */
    
    public class ScrollWebView extends WebView { 
        private static final String TAG = "ScrollWebView";
        public OnScrollListener listener;
    
        public ScrollWebView(Context context) {
            this(context,null);
        }
    
        public ScrollWebView(Context context, AttributeSet attrs) {
            this(context, attrs,0);
        }
    
        public ScrollWebView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
        }
    
        @Override
        protected void onScrollChanged(int l, int t, int oldl, int oldt) {
            super.onScrollChanged(l, t, oldl, oldt);
    
            if (listener != null){
                if (t - oldt <= 2){
                    listener.onScrollDown();
                }
                if(oldt - t >= 2) {
                    listener.onScrollUp();
                }
            }
        }
    
        public void setListener(OnScrollListener listener){
            this.listener = listener;
        }
    
        public interface OnScrollListener{ 
            void onScrollUp();//上滑
            void onScrollDown();//下滑
        }
    }

二：布局文件使用自定义的WebView

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
    
        <app.coolwhether.com.zhihudailynews.support.ScrollWebView android:id="@+id/webview" android:layout_width="match_parent" android:layout_height="match_parent"/>
    </LinearLayout>

三：引用该ScrollWebView

mWebView.setListener(new ScrollWebView.OnScrollListener() {
                @Override
                public void onScrollUp() {
                    getSupportActionBar().show();
                }
    
                @Override
                public void onScrollDown() {
                    getSupportActionBar().hide();
                }
    
    
            });

![效果图][SouthEast]

[SouthEast]: /images/20220711/3a87d3cd3a2a46c0a189fba97f6748e7.png