在ICS中脫節的WebView繪圖

我正在製作一個應用程序，該應用程序具有與其他元素嵌套在一起的Webview內嵌在ScrollView中的應用程序。我注意到，在ICS中，在Galaxy Nexus設備上進行測試時，當頁面被瀏覽時，WebView似乎與其餘顯示的元素不相關，導致WebView顯示爲浮動，因爲其值爲幾ms滯後於繪圖。在2.x版本的Android中不會發生這種情況（未在3.x上測試）。這裏有一個浮動效果的視頻http://www.youtube.com/watch?v=avfBoWmooM4（你可以清楚地看到，如果你設置爲全屏1080p）在ICS中脫節的WebView繪圖

任何人都可以提出爲什麼會發生這種情況，或修復？

我設置一個測試項目，下面，向人們展示：

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; 
     } 

    } 
}

來源

2011-12-05 Martyn

我不知道如何解決，但我現在的原因。 WebView的內容由android.webkit.WebViewCore在其單獨的工作線程中呈現。他們正在相互溝通。當WebView需要重新渲染時，它會向WebViewCore發送「請渲染」消息，並且WVC準備就緒時會發回結果。重點在於它們的渲染與其他UI元素的渲染不同步 - 因爲它是在單獨的非UI線程上完成的。

我想他們想避免所有的渲染工作阻塞ui線程。這非常友善。但它會導致其他問題......像你的問題。

來源

2012-02-17 15:36:42

在ICS中脫節的WebView繪圖

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