android - Android 上的 WebView 问题

Question

我使用下面的代码通过 WebView 读取 .html 文件，
并打开与其他浏览器应用程序的超链接。

webView = (WebView)findViewById(R.id.terms_of_services_webview);
String Path = "...";  //html file path
WebSettings websettings = webView.getSettings();  
websettings.setSupportZoom(true);  
websettings.setBuiltInZoomControls(true);   
websettings.setJavaScriptEnabled(true);  
webView.setWebViewClient(new WebViewClient() {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        if(url.equals(Path)) {
            view.loadUrl(url);
        }
        else {
            Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
            TermsOfServicesActivity.this.startActivity(intent);
        }
        return true;  
    }
});

webView.loadUrl(Path);  

代码都在onCreate方法中。

但我在 Galaxy Tab 8.9(Android 4.0.4) 上找到了错误代码:

11-20 16:24:49.613: W/webview(25896): java.lang.Throwable: Warning: A WebView method was called on thread 'WebViewCoreThread'. All WebView methods must be called on the UI thread. Future versions of WebView may not support use on other threads.
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebView.checkThread(WebView.java:14240)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebView.getSettings(WebView.java:5374)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebView.getVisibleTitleHeightImpl(WebView.java:2340)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebView.getViewHeight(WebView.java:2382)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebViewCore.setupViewport(WebViewCore.java:3421)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebViewCore.didFirstLayout(WebViewCore.java:3148)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.JWebCoreJavaBridge.nativeServiceFuncPtrQueue(Native Method)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.JWebCoreJavaBridge.handleMessage(JWebCoreJavaBridge.java:113)
11-20 16:24:49.613: W/webview(25896):   at android.os.Handler.dispatchMessage(Handler.java:99)
11-20 16:24:49.613: W/webview(25896):   at android.os.Looper.loop(Looper.java:137)
11-20 16:24:49.613: W/webview(25896):   at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:828)
11-20 16:24:49.613: W/webview(25896):   at java.lang.Thread.run(Thread.java:856)
11-20 16:24:49.623: E/StrictMode(25896): null
11-20 16:24:49.623: E/StrictMode(25896): java.lang.Throwable: Warning: A WebView method was called on thread 'WebViewCoreThread'. All WebView methods must be called on the UI thread. Future versions of WebView may not support use on other threads.
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebView.checkThread(WebView.java:14240)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebView.getSettings(WebView.java:5374)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebView.getVisibleTitleHeightImpl(WebView.java:2340)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebView.getViewHeight(WebView.java:2382)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebViewCore.setupViewport(WebViewCore.java:3421)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebViewCore.didFirstLayout(WebViewCore.java:3148)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.JWebCoreJavaBridge.nativeServiceFuncPtrQueue(Native Method)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.JWebCoreJavaBridge.handleMessage(JWebCoreJavaBridge.java:113)
11-20 16:24:49.623: E/StrictMode(25896):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-20 16:24:49.623: E/StrictMode(25896):    at android.os.Looper.loop(Looper.java:137)
11-20 16:24:49.623: E/StrictMode(25896):    at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:828)
11-20 16:24:49.623: E/StrictMode(25896):    at java.lang.Thread.run(Thread.java:856)

但它适用于 Xperia z11(Android 4.2.2)、Nexus 7 2013(Android 4.3.1)、ASUS TF201(Android 4.1.1) ).

为什么它不能在 4.0.3 上运行？
我怎样才能避免它？

Answer 1

正如警告所说，您正在调用 WebViewCoreThread 中的 webview 方法。因此像这样修改你的代码，

YourActivity.this.runOnUiThread(new Runnable() {
    public void run() {
       websettings.setSupportZoom(true);  
       websettings.setBuiltInZoomControls(true);   
       websettings.setJavaScriptEnabled(true);  
   webView.setWebViewClient(new WebViewClient() {
  @Override
  public boolean shouldOverrideUrlLoading(WebView view, String url) {
    if(url.equals(Path)) {
        view.loadUrl(url);
    }
    else {
        Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
        TermsOfServicesActivity.this.startActivity(intent);
    }
    return true;  
     }
 });

  webView.loadUrl(Path);  
     }
});

或

尝试在 setContentView() 之前的 onCreate() 方法中写入以下行。

  StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);