有没有办法使用javascript隐藏WebView中的按钮？A2HS按钮

编程问答 2022-08-23

问题描述

我有一个链接到我的商店网址的WebView应用程序，这里的问题是有一个按钮（添加到主屏幕）按钮，我想在我的WebView中隐藏该按钮类。我试图使用javascript将其隐藏在OnProgressChange方法中，它可以工作，但是，当我单击类别按钮并按主屏幕按钮或再次返回主屏幕时，再次出现“添加到主屏幕按钮”。有人可以帮我还是指导我如何完成这项任务。 this is the shop link 

  //WebView Settings and Configuration
    Wview = (WebView) findViewById(R.id.webView);
    WebSettings webSettings = Wview.getSettings();
    webSettings.setJavaScriptEnabled(true);
    Wview.setWebChromeClient(new chromeClient());
    Wview.setWebViewClient(new myClient());
    webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
    Wview.loadUrl(homeUrl);

}

private class myClient extends WebViewClient {
    @Override
    public void onPageStarted(WebView view,String url,Bitmap favicon) {
        super.onPageStarted(view,url,favicon);
    }

    @Nullable
    @Override
    public WebResourceResponse shouldInterceptRequest(WebView view,String url) {
        return super.shouldInterceptRequest(view,url);
    }

    @Override
    public boolean shouldOverrideUrlLoading(WebView view,String url) {
        boolean a = true;
        if (url !=null && url.startsWith("whatsapp")){
            view.getContext().startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse(url)));
            return true;
        }
        else if (url.startsWith("tel:")) {
            Intent intent = new Intent(Intent.ACTION_DIAL,Uri.parse(url));
            startActivity(intent);
        }
        else if (url.startsWith("rate:")) {
            final String app_package = getPackageName(); //requesting app package name from Context or Activity object
            try {
                startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse("market://details?id=" + app_package)));
            } catch (ActivityNotFoundException anfe) {
                startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse("https://play.google.com/store/apps/details?id=" + app_package)));
            }

        }
        else if (url.startsWith("share:")) {
            Intent intent = new Intent(Intent.ACTION_SEND);
            intent.setType("text/plain");
            intent.putExtra(Intent.EXTRA_SUBJECT,view.getTitle());
            intent.putExtra(Intent.EXTRA_TEXT,view.getTitle()+"\nVisit: "+(Uri.parse(url).toString()).replace("share:",""));
            startActivity(Intent.createChooser(intent,getString(R.string.share_w_friends)));
        }
         else if (url.startsWith("exit:")) {
          exitApp();
    }// opening external URLs in android default web browser
     else if (ext_url && !hostname(url).equals(homeUrl)) {
        Wview(url,true,wError_counter);
            // else return false for no special action
        } else {
            a = false;
        }
        return a;
    }

    @Override
    public void onPageFinished(WebView view,String url) {
        if(!errorOccured){
            findViewById(R.id.welcome).setVisibility(View.GONE);
            findViewById(R.id.webView).setVisibility(View.VISIBLE);

        }
        super.onPageFinished(view,url);
    }
    @Override
    public void onReceivedHttpError(WebView view,WebResourceRequest request,WebResourceResponse errorResponse) {

        super.onReceivedHttpError(view,request,errorResponse);
    }

    @Override
    public void onReceivedError(WebView view,WebResourceError error) {
        errorOccured=true;
        findViewById(R.id.webView).setVisibility(View.GONE);
        findViewById(R.id.welcome).setVisibility(View.VISIBLE);
        //Intent intent = new Intent(getApplicationContext(),ErrorActivity.class);
       // startActivity(intent);
    }


}

//Random ID creation function to help get fresh cache every-time webview reloaded
public String random_id() {
    return new BigInteger(130,random).toString(32);
}

//Opening URLs inside webview with request
void Wview(String url,Boolean tab,int error_counter) {
    if(error_counter > 2){
        wError_counter = 0;
        exitApp();
    }else {
        if(tab){
            if(cTAB) {
                CustomTabsIntent.Builder intentBuilder = new CustomTabsIntent.Builder();
                intentBuilder.setToolbarColor(ContextCompat.getColor(this,R.color.colorPrimary));
                intentBuilder.setSecondaryToolbarColor(ContextCompat.getColor(this,R.color.colorPrimaryDark));
                intentBuilder.setStartAnimations(this,android.R.anim.slide_in_left,android.R.anim.slide_out_right);
                intentBuilder.setExitAnimations(this,android.R.anim.slide_out_right);
                CustomTabsIntent customTabsIntent = intentBuilder.build();
                try {
                    customTabsIntent.launchUrl(MainActivity.this,Uri.parse(url));
                } catch (ActivityNotFoundException e) {
                    Intent intent = new Intent(Intent.ACTION_VIEW);
                    intent.setData(Uri.parse(url));
                    startActivity(intent);
                }
            }else{
                Intent intent = new Intent(Intent.ACTION_VIEW);
                intent.setData(Uri.parse(url));
                startActivity(intent);
            }
        } else {
            if (url.contains("?")) { // check to see whether the url already has query parameters and handle appropriately.
                url += "&";
            } else {
                url += "?";
            }
            url += "rid=" + random_id();
            Wview.loadUrl(url);
        }
    }
}


//Getting host name
public static String hostname(String url){
    if (url == null || url.length() == 0) {
        return "";
    }
    int dslash = url.indexOf("//");
    if (dslash == -1) {
        dslash = 0;
    } else {
        dslash += 2;
    }
    int end = url.indexOf('/',dslash);
    end = end >= 0 ? end : url.length();
    int port = url.indexOf(':',dslash);
    end = (port > 0 && port < end) ? port : end;
    Log.w("URL Host: ",url.substring(dslash,end));
    return url.substring(dslash,end);
}
private void exitApp() {
    Intent intent = new Intent(Intent.ACTION_MAIN);
    intent.addCategory(Intent.CATEGORY_HOME);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(intent);
}
// Creating exit dialogue
public void ask_exit(){
    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

    builder.setTitle(getString(R.string.exit_title));
    builder.setMessage(getString(R.string.exit_subtitle));
    builder.setCancelable(true);

    // Action if user selects 'yes'
    builder.setPositiveButton("Yes",new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface,int i) {
            finish();
        }
    });

    // Actions if user selects 'no'
    builder.setNegativeButton("No",int i) {
        }
    });

    // Create the alert dialog using alert dialog builder
    AlertDialog dialog = builder.create();

    // display the dialog when user press back button
    dialog.show();
}

@Override
public void onBackPressed() {
    if (Wview.canGoBack()) {
        Wview.goBack();
    } else if (ask_ExitDial) {
        ask_exit();
    } else {
        super.onBackPressed();
        this.finish();
    }
}

private class chromeClient extends WebChromeClient {

    @Override
    public void onProgressChanged(WebView view,int newProgress) {
        Wview.loadUrl("javascript:(function() { " +
                "document.getElementsByClassName('sc-iQKALj cdqULD border border-gray-dae')[0].style.display='none'; " +
                "})()");
        super.onProgressChanged(view,newProgress);
    }

}

private class touchlistener implements View.OnTouchListener {
    @Override
    public boolean onTouch(View view,MotionEvent motionEvent) {
        WebView.HitTestResult hitTestResult=((WebView)view).getHitTestResult();
        hitResult=true;
        return false;
    }
}
}

on starting the app there is no add to homescreen button

Add to home screen button after clicking the category button and going back to home

解决方法

所以基本上，问题是要检测WebView内部的更改并以特定的方式对其进行反应。

WebView内的更改可以有多种类型-实际的重新加载和Dom更改-是我们应该听的主要内容。尽管监听重装相对容易，并且可以在WebViewClient.shouldInterceptRequest或WebViewClient.shouldOverrideUrlLoading回调中完成，但无法通过android WebView API来跟踪DOM更改。

private class myClient extends WebViewClient {
    ...
    @Nullable
    @Override
    public WebResourceResponse shouldInterceptRequest(WebView view,String url) {
        Wview.evaluateJavascript("javascript:(function() { " +
                            "document.getElementsByClassName('sc-iQKALj cdqULD border border-gray-dae')[0].style.display='none'; " +
                            "})()");
        return super.shouldInterceptRequest(view,url);
    }
    ...
}

要跟踪DOM中的更改，我们可以使用JavaScript，特别是MutationObserver-您必须通过WebView js注入功能将代码与实现的回调一起注入。为此，如果您的最低API级别高于19，请尝试使用webView.evaluateJavascript而不是webView.loadUrl。

您也可以使用Activity.onBackPressed方法和WebView.setOnKeyListener结合词。看起来像这样：

public void onBackPressed() {
    if (Wview.canGoBack()) {
        Wview.goBack();
        Wview.evaluateJavascript("javascript:(function() { " +
                            "document.getElementsByClassName('sc-iQKALj cdqULD border border-gray-dae')[0].style.display='none'; " +
                            "})()");
    } else if (ask_ExitDial) {
        ask_exit();
    } else {
        super.onBackPressed();
        this.finish();
    }
}

Wview.setOnKeyListener((View.OnKeyListener) (v,keyCode,event) -> {
            if (event.getAction() != KeyEvent.ACTION_DOWN)
                return true;
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                if (Wview.canGoBack()) {
                    Wview.goBack();
                    Wview.evaluateJavascript("javascript:(function() { " +
                            "document.getElementsByClassName('sc-iQKALj cdqULD border border-gray-dae')[0].style.display='none'; " +
                            "})()");
                } else {
                    ((Activity) this).onBackPressed();
                }
                return true;
            }
            return false;
        });

它可能行不通，具体取决于您的网站体系结构。

因此，您唯一的选择是进行试验，并希望它会起作用。通常在android上使用webview是一件很痛苦的事，所以...是的。

希望它会以某种方式帮助您。

,

您可以使用 onPageFinished 方法执行JavaScript代码以隐藏按钮。

在onPageFinished方法内部使用此代码

Wview.evaluateJavascript("javascript:(function() { " +
                            "document.getElementsByClassName('sc-iQKALj cdqULD border border-gray-dae')[0].style.display='none'; " +
                            "})()");

注意：您还可以在onPageFinished方法中放置if语句，以检查当前URL是否与所需的URL模式匹配。

androidandroidbuttonbuttonjavascriptwebview

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