android webview不能弹出alert问题

关于webview不能弹出alert问题，

1、设置javascript 属性

WebSettings mWebSettings = webView.getSettings();
mWebSettings.setJavaScriptEnabled(true);

2、设置WebChromeClient属性

 webView.setWebViewClient(new WebViewClient() {})

下面是完成的webview 示例代码：

package com.example.mesapp;

import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.webkit.JsPromptResult;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.EditText;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;

import static android.view.KeyEvent.KEYCODE_BACK;


public class MainActivity extends AppCompatActivity {

    private WebView webView;

    ProgressDialog pro_dialog;

    //sop
//    String url = "http://192.168.1.2:96/index.html";
    //生产看板
//    String url = "http://192.168.1.2:92/index.html";

//    String url = "http://www.baidu.com";

    //ajax 测试网站
    String url = "http://192.168.3.26:96/index.html";

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        pro_dialog = new ProgressDialog(this);


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


//        webView = new WebView(this);
//        webView = findViewById(R.id.wv);
        webView = new CustomWebView(this);

        if (Build.VERSION.SDK_INT >=Build.VERSION_CODES.KITKAT) {
            Log.d("Test","------------可以远程调试-----------------");
            WebView.setWebContentsDebuggingEnabled(true);
        }

        WebSettings mWebSettings = webView.getSettings();


        mWebSettings.setJavaScriptEnabled(true);//设置支持javaScript
//        mWebSettings.setPluginsEnabled(true);
        mWebSettings.setUseWideViewPort(true); //将图片调整到适合webview的大小
        mWebSettings.setLoadWithOverviewMode(true); // 缩放至屏幕的大小
        mWebSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);
//        webView.setWebContentDebuggingEnabled(true);
        mWebSettings.setUserAgentString("User-Agent");
        mWebSettings.setLightTouchEnabled(true);//设置用鼠标激活被选项
        mWebSettings.setBuiltInZoomControls(true);//设置支持缩放
        mWebSettings.setDomStorageEnabled(true);//设置DOM缓存，当H5网页使用localStorage时，一定要设置
        mWebSettings.setDatabaseEnabled(true);
        mWebSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);//设置去缓存，防止加载的为上一次加载过的

        mWebSettings.setSupportZoom(true);//设置支持变焦
        webView.setHapticFeedbackEnabled(false);
        mWebSettings.setPluginState(WebSettings.PluginState.ON);
        mWebSettings.setAllowFileAccess(true);
        mWebSettings.setAllowContentAccess(true);
        mWebSettings.setAllowUniversalAccessFromFileURLs(true);
        mWebSettings.setAllowFileAccessFromFileURLs(true);


//        webView.addJavascriptInterface(this,"android");//与js交互使用，没需求可以注释掉



        webView.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);
                Log.d("MainActivity","开始加载");
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                super.onPageFinished(view, url);
                Log.d("MainActivity","加载结束");
            }

            // 链接跳转都会走这个方法
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                Log.d("MainActivity","Url："+ url );
                view.loadUrl(url);// 强制在当前 WebView 中加载 url
                return true;
            }
        });

        //设置响应js 的Alert()函数
        webView.setWebChromeClient(new WebChromeClient() {
            @Override
            public void onProgressChanged(WebView view, int newProgress) {
                super.onProgressChanged(view, newProgress);
                Log.d("MainActivity","newProgress："+ newProgress );
            }

            @Override
            public void onReceivedTitle(WebView view, String title) {
                super.onReceivedTitle(view, title);
                Log.d("MainActivity","标题："+ title);
            }


            @Override
            public boolean onJsAlert(WebView view, String url, String message, final JsResult result) {
                AlertDialog.Builder b = new AlertDialog.Builder(MainActivity.this);
                b.setTitle("");
                b.setMessage(message);
                b.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        result.confirm();
                    }
                });
                b.setCancelable(false);
                b.create().show();
                return true;
            }
            //设置响应js 的Confirm()函数
            @Override
            public boolean onJsConfirm(WebView view, String url, String message, final JsResult result) {
                AlertDialog.Builder b = new AlertDialog.Builder(MainActivity.this);
                b.setTitle("");
                b.setMessage(message);
                b.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        result.confirm();
                    }
                });
                b.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        result.cancel();
                    }
                });
                b.create().show();
                return true;
            }

            @Override
            public boolean onJsPrompt(WebView view, String url, String message, String defaultValue,
                                      final JsPromptResult result) {

//                mReusultText.setText("Prompt input is :" + message);
                result.confirm();
                return super.onJsPrompt(view, url, message, message, result);
            }

        });


        webView.loadUrl(url);

        setContentView(webView);



    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if ((keyCode == KEYCODE_BACK) && webView.canGoBack()) {
            webView.goBack();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    protected void onDestroy() {
        //释放资源
        if (webView != null)
            webView.destroy();
        super.onDestroy();
    }



}