1. 遇见问题及解决

• 1. 遇见 chromium: [INFO:CONSOLE(1)] "Uncaught ReferenceError: test is not defined", source: (1) ，这里是调用了 html 的 test 方法，显示的错误信息是 undefined
     解决：因为调用 js 里的方法时有两种方法，一种是有返回值，一种是没用返回值，这里是使用了没用返回值的函数调用方式。有两种函数调用的方式：

1. webView.loadUrl("javascript:test()");    // 直接调用

2. String script=String.format("javascript:test()");    // 处理返回值
                webView.evaluateJavascript(script, new ValueCallback<String>() {
                    @Override
                    public void onReceiveValue(String s) {
                        Log.i("Wooo", "onReceiverValue : " + s);    //返回字符串
                    }
                });

2. JS 与 java 互调

1. js 调 java

在 java 内声明被调函数，并处理逻辑。AAAA 参数是标识字段，在 JS 内会使用到，并作为调用 java 函数的句柄，arg 是 JS 串给 java 的参数

webView.addJavascriptInterface(new JSInterface(), "AAAA");

    private class JSInterface {
        @JavascriptInterface
        public void showToast(String arg){
            Toast.makeText(MainActivity.this,arg, Toast.LENGTH_SHORT).show();
        }
    }

js 调用代码，句柄、函数名要对应上

    window.AAAA.showToast('JS中传来的参数');

2. java 调 js

上面说到，有两种调用方式，一个是有参数，一个是无参数返回

                //webView.loadUrl("javascript:callJS()");    // 方式一
                String script=String.format("javascript:test('i call js')");
                webView.evaluateJavascript(script, new ValueCallback<String>() {      // 方式二
                    @Override
                    public void onReceiveValue(String s) {
                        Log.i("Wooo", "onReceiverValue : " + s);
                    }
                });

3. 完整代码

• MainActivity

import android.annotation.SuppressLint;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.webkit.JavascriptInterface;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private WebView webView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();

        Button b = (Button) findViewById(R.id.bbb);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //webView.loadUrl("javascript:callJS()");
                String script=String.format("javascript:test('i call js')");
                webView.evaluateJavascript(script, new ValueCallback<String>() {
                    @Override
                    public void onReceiveValue(String s) {
                        Log.i("Wooo", "onReceiverValue : " + s);
                    }
                });
            }
        });
    }

    private void init() {
        webView  = (WebView) findViewById(R.id.webView);
        webView.setWebViewClient(new myWebViewClient());
        WebSettings settings = webView.getSettings();
        webView.setWebChromeClient(new myWebChromeClient(MainActivity.this));
        settings.setJavaScriptEnabled(true);
        settings.setDefaultTextEncodingName("utf-8");
        webView.addJavascriptInterface(new JSInterface(), "AAAA");
        webView.loadUrl("file:///android_asset/index.html");//http://www.exchen.net/test/index.html  file:///android_asset/index.html
    }

    private class JSInterface {
        @JavascriptInterface
        public void showToast(String arg){
            Toast.makeText(MainActivity.this,arg, Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (webView.canGoBack()) {
                webView.goBack();
                return true;
            } else {
                System.exit(0);
            }
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        webView.stopLoading();
        webView.removeAllViews();
        if (webView != null) {
            webView.destroy();
            webView = null;
        }
    }
}

• index.xml

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>API</title>
</head>
<body>
<script>
  var cpp_object;
  if (cpp_object != null){
    cpp_object.PageCommunicatesWithTheClient("MSG:HTML to App");
  }
  function successData(response) {
    alert('MSG From App:'+response);
  }
  function test() {
    alert('test');
    return "testtt";
  }
  function callJS(){
      alert("Android调用了JS的callJS方法");
      return "callJS";
  }
  function test(var1) {
    alert(var1);
    window.AAAA.showToast('JS中传来的参数');
    return var1;
  }
</script>
</body>
</html>

• myWebChromeClient

import android.app.ProgressDialog;
import android.content.Context;
import android.util.Log;
import android.webkit.JsResult;
import android.webkit.WebChromeClient;
import android.webkit.WebView;

/**
 * Created by Administrator on 2018/3/24.
 */

public class myWebChromeClient extends WebChromeClient {
    private ProgressDialog dialog;
    private Context mContext;

    public myWebChromeClient(Context ctx) {
        mContext = ctx;
    }

    @Override
    public void onProgressChanged(WebView view, int newProgress) {
        if (newProgress == 100) {
            closeDialog();
        } else {
            openDialog(newProgress);
        }
    }

    private void openDialog(int newProgress) {
        if (dialog == null) {
            dialog = new ProgressDialog(mContext);
            dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            dialog.setProgress(newProgress);
            dialog.setCancelable(true);
            dialog.show();
        } else {
            dialog.setProgress(newProgress);
        }
    }

    private void closeDialog() {
        if (dialog != null && dialog.isShowing()) {
            dialog.dismiss();
            dialog = null;
        }
    }

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

    @Override
    public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
        Log.i("Wooo", "onJSAlert : " + url + ", message : " + message + ", result : " + result);
        return super.onJsAlert(view, url, message, result);
    }
}

• myWebViewClient

import android.webkit.WebView;
import android.webkit.WebViewClient;

/**
 * Created by Administrator on 2018/3/24.
 */

public class myWebViewClient extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;    //返回值是true的时候是控制网页在WebView中去打开，如果为false调用系统浏览器或第三方浏览器打开
    }
}

• activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="cn.saliey.vsoc.MainActivity">

    <Button
        android:id="@+id/bbb"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="40dp"
        android:layout_marginRight="20dp"
        android:textSize="16sp"
        android:text="确定" />

    <!--<TextView-->
        <!--android:layout_width="wrap_content"-->
        <!--android:layout_height="wrap_content"-->
        <!--android:text="Hello World!"-->
        <!--app:layout_constraintBottom_toBottomOf="parent"-->
        <!--app:layout_constraintLeft_toLeftOf="parent"-->
        <!--app:layout_constraintRight_toRightOf="parent"-->
        <!--app:layout_constraintTop_toTopOf="parent" />-->
    <WebView
        android:id="@+id/webView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</android.support.constraint.ConstraintLayout>

• 声明权限

    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.android.vending.BILLING" />