如何在Webview中向下滚动时隐藏ActionBar /工具栏

Question

在Google Chrome和Play商店中.应用程序可以在滚动时隐藏操作栏,并允许用户方便地浏览.请帮我这样做.

我使用onTouchListener进行webview它不起作用.

mWebView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:
                        getSupportActionBar().show();
                            break;
                    case MotionEvent.ACTION_UP:
                        getSupportActionBar().hide();
                            break;
                    default: break;
                }
                return false;
            }
        });

提前致谢

Answer 1

您可以使用设计库的做到这一点没有任何Java代码CoordinatorLayout,并NestedScrollView与app:layout_scrollFlags集上Toolbar.这是你如何做到的.

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:layout_scrollFlags="scroll|enterAlways"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
</android.support.design.widget.AppBarLayout>

<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="fill_vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <WebView
        android:id="@+id/webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

一旦掌握了它,你就可以使用不同的layout_scrollFlags和fitsSystemWindows行为.

Answer 2

好吧,我已经实现了CustomWebView和GestureDetector:

CustomWebView.java:

public class CustomWebView extends WebView {
    private GestureDetector gestureDetector;
    public CustomWebView(Context context) {
        super(context);
    }
    public CustomWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public CustomWebView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        return gestureDetector.onTouchEvent(ev) || super.onTouchEvent(ev);
    }

    public void setGestureDetector(GestureDetector gestureDetector) {
        this.gestureDetector = gestureDetector;
    }
}

web_fragment.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent"
    android:orientation="vertical">

   <com.customview.CustomWebView
            android:id="@+id/customWebView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:focusable="true" />

</LinearLayout>

用于手势检测的CustomeGestureDetector clss(我在Fragment中添加了):

private class CustomeGestureDetector extends GestureDetector.SimpleOnGestureListener {
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            if(e1 == null || e2 == null) return false;
            if(e1.getPointerCount() > 1 || e2.getPointerCount() > 1) return false;
            else {
                try {
                    if(e1.getY() - e2.getY() > 20 ) {
                            // Hide Actionbar
                        getSupportActionBar().hide();
                        customWebView.invalidate();
                       return false;
                    }
                    else if (e2.getY() - e1.getY() > 20 ) {
                            // Show Actionbar
                        getSupportActionBar().show();
                        customWebView.invalidate();
                       return false;
                    }

                } catch (Exception e) {
                    customWebView.invalidate();
                }
                return false;
            }


        }
    }

WebFragment.java:

private CustomWebView customWebView;

customWebView= (CustomWebView) view.findViewById(R.id.customWebView);

customWebView.setGestureDetector(new GestureDetector(new CustomeGestureDetector()));

它适用于我,希望它会帮助你.