12

这是我的布局。当我加载 google.com 时，webview 的高度会无限增长。webview 的 onSizeChange 函数不断被调用，我可以看到 webview 不断扩展。我已经尝试了 design 和 appcompat 库的 22.2.1 和 23.1.0 并且没有效果。

有什么解决办法吗？:-|

<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:background="@android:color/black">

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="fill_vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <com.example.ajay.scrollabletoolbar.MyWebView
        android:id="@+id/webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"/>
</android.support.v4.widget.NestedScrollView>

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbarlayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true">

    <android.support.v7.widget.Toolbar
        android:id="@+id/restricted_browser_toolbar"
        android:layout_width="match_parent"
        android:layout_height="?actionBarSize"
        android:background="@color/colorPrimary"
        app:layout_scrollFlags="scroll|enterAlways">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#FFFFFF"
            android:descendantFocusability="beforeDescendants"
            android:focusableInTouchMode="true">

            <EditText
                android:id="@+id/current_url"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_centerVertical="true"
                android:backgroundTint="@android:color/darker_gray"
                android:dropDownAnchor="@+id/restricted_browser_toolbar"
                android:hint="hint hint"
                android:imeOptions="actionGo|flagNoExtractUi"
                android:inputType="textNoSuggestions|textUri"
                android:paddingBottom="8dp"
                android:paddingEnd="8dp"
                android:paddingStart="8dp"
                android:singleLine="true"/>

            <ImageView
                android:id="@+id/clear_url_text"
                android:layout_width="48dp"
                android:layout_height="48dp"
                android:layout_alignRight="@+id/current_url"
                android:layout_centerVertical="true"
                android:layout_marginRight="8dp"
                android:src="@android:drawable/ic_menu_close_clear_cancel"
                android:visibility="gone"/>
        </RelativeLayout>
    </android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>

4

2 回答 2

11

In one sentence, you just can't put your WebView inside NestedScrollView. This is working as intended.

If you put a WebView inside NestedScrollView (or ScrollView), your WebView measures its dimensions with View.MeasureSpec.UNSPECIFIED requirement. No matter you set MATCH_PARENT or even fixed size like 100dp for your WebView's height. NestedScrollView forces its children measure themselves with View.MeasureSpec.UNSPECIFIED requirement. It all happens at NestedScrollView's measureChild() method. It goes like below :

@Override
protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) {
    ViewGroup.LayoutParams lp = child.getLayoutParams();
    int childWidthMeasureSpec;
    int childHeightMeasureSpec;
    childWidthMeasureSpec = getChildMeasureSpec(parentWidthMeasureSpec, getPaddingLeft()
            + getPaddingRight(), lp.width);
    childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}

And MeasureSpec.UNSPECIFIED means, as its label implies, it can be whatever size it wants. I think this slide from the "Writing Custom Views for Android" session at Google I/O 2013 will help you to understand it.

enter image description here

Actually this is an issue which was discussed in this thread, and according to this Google engineer,

This is as if in desktop, you resize the browser window to height of the page so it can't scroll vertically. The scrolling is happening in NestedScrollView rather than webview itself. So a consequence of no js in the page sees any scroll events, so it doesn't know you've scrolled to the end of the page load more content.

So, bottom line is, DO NOT put your WebView inside NestedScrollView. You should let WebView scroll the web page itself. Happy coding! :)

于 2016-06-20T01:17:36.220 回答
1

我很抱歉没有早点结束这个问题。我们不能将 webview 放在 nestedScrollView 中。但是 NSV 的本质是，它将其子级扩展到其全高，以便它可以使用工具栏按预期工作以获得可折叠/可滚动的工具栏等。因此，如果添加 webview，webview 将无限增长或增长到很大值，因此它不会按预期工作。这可以是参考：code.google.com/p/android/issues/detail?id=198965

于 2016-06-21T19:28:29.923 回答