Js Java call each other

Two ultra-detailed conscience strategies

https://www.jianshu.com/p/3c94ae673e2a web view API introduction

https://www.jianshu.com/p/345f4d8a5cfa java js intermodulation

java calls js

prepare an html file

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Carson_Ho</title>
    <script>
function callJS(){

   
      alert("Android called the callJS method of JS ");
   }
    </script>
</head>
</html>

transfer

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "xbh";
    private WebView wv;
@SuppressLint("SetJavaScriptEnabled")
    @Override
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FrameLayout fl = findViewById(R.id.fl);
wv = new WebView(this);
Button bt = findViewById(R.id.bt)

                
                        ;
fl.addView(wv);
WebSettings ws = wv.getSettings();
ws.setJavaScriptEnabled(true);
ws.setJavaScriptCanOpenWindowsAutomatically(true);
wv.loadUrl("file:///android_asset/javascript.html");
wv.setWebViewClient(new WebViewClient() {
            @Override
public void onPageFinished(WebView view, String url) {
        
                        
        
                    
                Log.i(TAG, "LoadFinished: ");
                view.loadUrl("javascript:callJS()");
            }
        });
wv.setWebChromeClient(new WebChromeClient() {
            @Override
public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
                    
                Log.i(TAG, "onJsAlert: " + url + " " + message + " " + result);
                return true;
            }
        });
    }
}

You can also use evaluateJavascript()->4.4 and above to use this method

js calls java

1.addJavascriptInterface（）

js code

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Carson</title>
    <script>
         function callAndroid(){
            test.hello("js调用了android中的hello方法");
         }
    </script>
</head>
<body>
</body>
</html>

java

package com.example.demo;

import android.annotation.SuppressLint;
import android.app.job.JobInfo;
import android.app.job.JobScheduler;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.JavascriptInterface;
import android.webkit.JsResult;
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.FrameLayout;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "xbh";

    private WebView wv;

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

        FrameLayout fl = findViewById(R.id.fl);
        wv = new WebView(this);

        fl.addView(wv);

        wv.loadUrl("file:///android_asset/javascript.html");

        wv.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageFinished(WebView view, String url) {
                view.loadUrl("javascript:callAndroid()");
            }
        });

        WebSettings ws = wv.getSettings();
        ws.setJavaScriptEnabled(true);
        wv.addJavascriptInterface(new AndroidtoJs(), "test");//AndroidtoJS类对象映射到js的test对象
    }

    class AndroidtoJs{
        @JavascriptInterface
        public void hello(String msg) {
            Toast.makeText(MainActivity.this, msg, Toast.LENGTH_SHORT).show();
            Log.i(TAG, msg);
        }
    }
}

但是有漏洞

2.shouldOverrideUrlLoading拦截url

3.拦截alert()、confirm()、prompt（）

还有就是用JsBridge等框架

Js Java call each other

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