Question

我正在创建一个Webview与其他元素内联的应用程序，嵌套在ScrollView中。我注意到在ICS中，在Galaxy Nexus设备上进行测试时，当页面被抛出时，WebView似乎与其余显示的元素脱节，导致WebView看起来漂浮，因为它有几毫秒的价值。落后于绘画。这不会发生在Android的2.x版本中（未在3.x上测试）。这是一个浮动效果http://www.youtube.com/watch?v=avfBoWmooM4的视频（如果你设置为1080p全屏，你可以看清楚）

任何人都可以建议为什么会发生这种情况或修复？

我在下面设置了一个测试项目来演示：

package com.martynhaigh.floating_web_view;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;

public class FloatingWebViewTestActivity extends FragmentActivity {
    public final int viewId = 0x12345678;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        FrameLayout frame = new FrameLayout(this);
        frame.setId(viewId);
        setContentView(frame, lp);

        FloatingWebViewICSFragment fragment = new FloatingWebViewICSFragment();
        getSupportFragmentManager().beginTransaction().add(viewId, fragment).commit();
    }

    public static class FloatingWebViewICSFragment extends Fragment {

        private final String htmlBody = "<html><body><p style=\"font-size:1.5em\">This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. This is a test document. </body></html>";

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

            TextView textView = new TextView(getActivity().getApplicationContext());
            textView.setText("Test Activity");

            WebView webView = new WebView(getActivity().getApplicationContext());
            webView.loadDataWithBaseURL("file:///android_asset/", htmlBody, "text/html", "UTF-8", "about:blank");
            webView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
            webView.setScrollContainer(false);

            TextView textView2 = new TextView(getActivity().getApplicationContext());
            textView2.setText("Test Activity");

            FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.FILL_PARENT);

            LinearLayout layout = new LinearLayout(getActivity().getApplicationContext());
            layout.setLayoutParams(lp);
            layout.setOrientation(LinearLayout.VERTICAL);

            layout.addView(textView);
            layout.addView(webView);
            layout.addView(textView2);

            ScrollView scrollView = new ScrollView(getActivity().getApplicationContext());
            scrollView.setLayoutParams(lp);
            scrollView.addView(layout);

            return scrollView;
        }

    }
}

Answer 1

我不知道如何解决它，但我现在的原因。 WebView的内容由android.webkit.WebViewCore在其单独的工作线程中呈现。他们正在相互沟通。当WebView需要重新渲染时，它会向WebViewCore发送“please render”消息，当WVC准备就绪时，然后发送回结果。关键是它们的渲染与其他UI元素的渲染不同步 - 因为它是在一个单独的非ui线程上完成的。

我猜他们想避免在所有渲染工作中阻止ui-thread。那很亲切。但它会导致其他问题......就像你的一样。

ICS中脱节的WebView绘图

1 个答案: