Java Android Webview乘法方法可以'；无法解决

我目前正在编写一个应用程序，将我的网站带入其中。我还请求了权限，但现在无法解决

onCreate

、

setContentView

和

findViewById

的问题（它们几乎都在编码的末尾）。 以下是我的MainActivity.java：

package org.youtivity.youtivity;

import android.os.Bundle;
import android.Manifest;
import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.util.Log;
import android.webkit.GeolocationPermissions;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.support.v4.app.ActivityCompat;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static android.content.ContentValues.TAG;

    public class MainActivity extends Activity {

        public static final int REQUEST_ID_MULTIPLE_PERMISSIONS = 1;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            if(checkAndRequestPermissions()) {
                // carry on the normal flow, as the case of  permissions  granted.
            }
        }

        private  boolean checkAndRequestPermissions() {
            int permissionSendMessage = ContextCompat.checkSelfPermission(this,
                    Manifest.permission.READ_EXTERNAL_STORAGE);
            int locationPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
            List<String> listPermissionsNeeded = new ArrayList<>();
            if (locationPermission != PackageManager.PERMISSION_GRANTED) {
                listPermissionsNeeded.add(Manifest.permission.ACCESS_FINE_LOCATION);
            }
            if (permissionSendMessage != PackageManager.PERMISSION_GRANTED) {
                listPermissionsNeeded.add(Manifest.permission.READ_EXTERNAL_STORAGE);
            }
            if (!listPermissionsNeeded.isEmpty()) {
                ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]),REQUEST_ID_MULTIPLE_PERMISSIONS);
                return false;
            }
            return true;
        }

        public void onRequestPermissionsResult(int requestCode,
                                               String permissions[], int[] grantResults) {
            Log.d(TAG, "Permission callback called-------");
            switch (requestCode) {
                case REQUEST_ID_MULTIPLE_PERMISSIONS: {

                    Map<String, Integer> perms = new HashMap<>();
                    // Initialize the map with both permissions
                    perms.put(Manifest.permission.READ_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
                    perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
                    // Fill with actual results from user
                    if (grantResults.length > 0) {
                        for (int i = 0; i < permissions.length; i++)
                            perms.put(permissions[i], grantResults[i]);
                        // Check for both permissions
                        if (perms.get(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
                                && perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                            Log.d(TAG, "sms & location services permission granted");
                            // process the normal flow
                            //else any one or both the permissions are not granted
                        } else {
                            Log.d(TAG, "Some permissions are not granted ask again ");
                            //permission is denied (this is the first time, when "never ask again" is not checked) so ask again explaining the usage of permission
                         // shouldShowRequestPermissionRationale will return true
                            //show the dialog or snackbar saying its necessary and try again otherwise proceed with setup.
                            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.SEND_SMS) || ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) {
                                showDialogOK("SMS and Location Services Permission required for this app",
                                        new DialogInterface.OnClickListener() {
                                            @Override
                                            public void onClick(DialogInterface dialog, int which) {
                                                switch (which) {
                                                    case DialogInterface.BUTTON_POSITIVE:
                                                        checkAndRequestPermissions();
                                                        break;
                                                    case DialogInterface.BUTTON_NEGATIVE:
                                                        // proceed with logic by disabling the related features or quit the app.
                                                        break;
                                                }
                                            }
                                        });
                            }
                            //permission is denied (and never ask again is  checked)
                            //shouldShowRequestPermissionRationale will return false
                            else {
                                Toast.makeText(this, "Go to settings and enable permissions", Toast.LENGTH_LONG)
                                        .show();
                                //                            //proceed with logic by disabling the related features or quit the app.
                            }
                        }
                    }
                }
            }

        }

        private void showDialogOK(String message, DialogInterface.OnClickListener okListener) {
            new AlertDialog.Builder(this)
                    .setMessage(message)
                    .setPositiveButton("OK", okListener)
                    .setNegativeButton("Cancel", okListener)
                    .create()
                    .show();
        }





        /**
         * WebViewClient subclass loads all hyperlinks in the existing WebView
         */
        public class GeoWebViewClient extends WebViewClient {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                // When user clicks a hyperlink, load in the existing WebView
               // view.loadUrl(url);
               // return true;
                String url2="https://www.youtivity.org/";
                // all links  with in ur site will be open inside the webview
                //links that start ur domain example(http://www.example.com/)
                if (url != null && url.startsWith(url2)){
                    return false;
                }
                // all links that points outside the site will be open in a normal android browser
                else  {
                    view.getContext().startActivity(
                            new Intent(Intent.ACTION_VIEW, Uri.parse(url)));
                    return true;
                }
            }
            }
        }


        /**
         * WebChromeClient subclass handles UI-related calls
         * Note: think chrome as in decoration, not the Chrome browser
         */
        public class GeoWebChromeClient extends WebChromeClient {
            @Override
            public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback) {
                // Always grant permission since the app itself requires location
                // permission and the user has therefore already granted it
                callback.invoke(origin, true, false);
            }
        }


        WebView mWebView;

        /** Called when the activity is first created. */
        @Override //<------Error HERE (does not overwrite)
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState); //<------Error HERE (onCreate)
            setContentView(R.layout.activity_main); //<------Error HERE (setContentView)
            mWebView = (WebView) findViewById(R.id.webView);//<------Error HERE (findViewById)
            mWebView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
            mWebView.getSettings().setBuiltInZoomControls(true);
            mWebView.setWebViewClient(new GeoWebViewClient());//<------Error HERE (GeoWebViewClient)

            mWebView.getSettings().setAppCacheEnabled(true);
            mWebView.getSettings().setDatabaseEnabled(true);
            mWebView.getSettings().setDomStorageEnabled(true);
            mWebView.getSettings().setJavaScriptEnabled(true);
            mWebView.setWebViewClient(new WebViewClient() {
                public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                    mWebView.loadUrl("file:///android_asset/noinet.html");

                }
            });
            mWebView.getSettings().setGeolocationEnabled(true);
            mWebView.setWebChromeClient(new GeoWebChromeClient());
            mWebView.getSettings().setBuiltInZoomControls(false);
            mWebView.loadUrl("https://www.youtivity.org");
        }

        @Override
        public void onBackPressed() {
            // Pop the browser back stack or exit the activity
            if (mWebView.canGoBack()) {
                mWebView.goBack();
            }
            else {
                super.onBackPressed();
            }
        }
    }

package org.youtivity.youtivity；
导入android.os.Bundle；
导入android.Manifest；
导入android.app.Activity；
导入android.content.DialogInterface；
导入android.content.Intent；
导入android.content.pm.PackageManager；
导入android.net.Uri；
导入android.support.v4.content.ContextCompat；
导入android.support.v7.app.AlertDialog；
导入android.util.Log；
导入android.webkit.GeolocationPermissions；
导入android.webkit.WebChromeClient；
导入android.webkit.WebView；
导入android.webkit.WebViewClient；
导入android.support.v4.app.ActivityCompat；
导入android.widget.Toast；
导入java.util.ArrayList；
导入java.util.HashMap；
导入java.util.List；
导入java.util.Map；
导入静态android.content.ContentValues.TAG；
公共类MainActivity扩展了活动{
公共静态最终整数请求\u ID\u多个\u权限=1；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
如果（检查并请求权限（））{
//在授予权限的情况下，执行正常流程。
}
}
私有布尔校验和请求权限（）{
int permissionSendMessage=ContextCompat.checkSelfPermission（此，
清单。权限。读取（外部存储）；
int locationPermission=ContextCompat.checkSelfPermission（这是Manifest.permission.ACCESS\u FINE\u位置）；
List ListPermissionsNeed=new ArrayList（）；
if（locationPermission！=已授予PackageManager.PERMISSION）{
listPermissionsNeed.add（Manifest.permission.ACCESS\u FINE\u位置）；
}
if（permissionSendMessage！=PackageManager.PERMISSION\u已授予）{
listPermissionsNeed.add（Manifest.permission.READ\u外部存储）；
}
如果（！ListPermissionsNeed.isEmpty（））{
ActivityCompat.requestPermissions（此，ListPermissionsNeed.toArray（新字符串[ListPermissionsNeed.size（）），请求\u ID\u多个\u权限）；
返回false；
}
返回true；
}
公共无效onRequestPermissionsResult（int requestCode，
字符串权限[]，int[]grantResults）{
Log.d（标记“权限回调调用----------------”）；
开关（请求代码）{
案例请求\u ID\u多个\u权限：{
Map perms=new HashMap（）；
//使用这两个权限初始化映射
perms.put（Manifest.permission.READ_EXTERNAL_STORAGE，PackageManager.permission_grated）；
perms.put（Manifest.permission.ACCESS\u FINE\u位置，PackageManager.permission\u已授予）；
//填写用户的实际结果
如果（grantResults.length>0）{
for（int i=0；i