WebView 错误页处理

作者: 霁逸lei | 来源:发表于2021-07-11 11:59 被阅读0次

WebView 错误页处理
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WebView 错误页加载后刷新回原页面

WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
settings.setBlockNetworkImage(false);
settings.setDomStorageEnabled(true);
if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.LOLLIPOP) {
    settings.setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW);
}
//跳转网页仍然在当前WebView中显示
webView.setWebViewClient(new WebViewClient(){

    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
        super.onPageStarted(view, url, favicon);
        //保存加载错误界面前的url
        if (!url.contains("error/index.html")){
            webView.setTag(url);
        }
    }

    // 旧版本，会在新版本中也可能被调用，所以加上一个判断，防止重复显示
    @Override
    public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
        super.onReceivedError(view, errorCode, description, failingUrl);
        Log.d("WebViewEmptyActivity", "error.getErrorCode():" +errorCode+description);
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
            return;
        }
        // 在这里显示自定义错误页
        showErrorHtml(view);
    }

    // 新版本，只会在Android6及以上调用
    @TargetApi(Build.VERSION_CODES.M)
    @Override
    public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
        super.onReceivedError(view, request, error);
        Log.d("WebViewEmptyActivity", "error.getErrorCode():" + error.getErrorCode()+error.getDescription());
        if (request.isForMainFrame()){ // 或者： if(request.getUrl().toString() .equals(getUrl()))
            showErrorHtml(view);
        }
    }
});
webView.setWebChromeClient(new WebChromeClient(){
    /**
     * 当WebView加载之后，返回 HTML 页面的标题 Title
     * @param view
     * @param title
     */
    @Override
    public void onReceivedTitle(WebView view, String title) {
        super.onReceivedTitle(view, title);
        // android 6.0 以下通过title获取判断
        if (!TextUtils.isEmpty(title)) {
            if (title.contains("404") || title.contains("500") || title.contains("Error") || title.contains("找不到网页") || title.contains("网页无法打开")) {
                showErrorHtml(view);
            }
        }
    }
});
webView.loadUrl("https://www.baidu.com");

private void showErrorHtml(WebView view) {
  view.loadUrl("about:blank");// 避免出现默认的错误界面
  webView.loadUrl("file:///android_asset/error/index.html")
}

public void refresh(){
    webView.clearCache(true);
    Object tag = webView.getTag();
    if (tag!=null){
        webView.loadUrl(tag.toString());
        return;
    }
    webView.reload();
}

WebView 与H5 交互

WebSettings settings = webView.getSettings();
settings.setJavaScriptEnabled(true);
webView.addJavascriptInterface(new AndroidForJs(this),"AndroidView");
public class AndroidForJs {
    private Context context;

    public AndroidForJs(Context context) {
        this.context = context;
    }

    //api17以后，只有public且添加了 @JavascriptInterface 注解的方法才能被调用
    @JavascriptInterface
    public void showToast(String toast) {
        Toast.makeText(context, "js调用android showToast():" + toast, Toast.LENGTH_SHORT).show();
    }

}

H5
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>菜鸟教程(runoob.com)</title>
    <script type="text/javascript">
function myFunction(toast){
    alert("stoast"+toast);
    //AndroidView与原生约定的字段
    window.AndroidView.showToast(toast);
}
</script>
</head>
<body>

<p>单击按钮触发函数。</p>
<button onclick="myFunction('aaa')">点我</button>
<p id="demo"></p>

</body>
</html>