Android webView 注入js文件，及交互

0.js文件:

链接：https://pan.baidu.com/s/1MaWKxgkYgQTVQCgn8-dxLg
提取码：o6wy

1. 读取js文件内容

 /**
     * 获取js文件内容
     *
     * @param context  参数为当前上下文对象
     * @param fileName 参数为要获取的js文件名称
     * @return
     */
    public static String getJS(Context context, String fileName) {
        InputStream inputStream = null;
        ByteArrayOutputStream outputStream = null;
        try {
            inputStream = context.getAssets().open(fileName);
            outputStream = new ByteArrayOutputStream();
            int len = 0;
            byte[] buffer = new byte[2048];
            while ((len = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, len);
            }
            return new String(outputStream.toByteArray());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

}

 webViewsettings.setJavaScriptEnabled(true);

3.添加js要调用的Android方法

public class JavaScriptUtil {
    @JavascriptInterface
    public void pushMessage(String serialNumber, String params, String methodName) {
   Log.i("serialNumber",serialNumber);
   Log.i("params",params);
   Log.i("methodName",methodName);
  EventBusCarrier eventBusCarrier = new EventBusCarrier();
        eventBusCarrier.setEventType(EventTypeGlobal.CONTACT_CHANGED_TYPE);
        if (TextUtils.equals(methodName, "testMethod")) {
          // 处理并发送消息
            eventBusCarrier.setEventType(methodName);
            eventBusCarrier.setObject(serialNumber);
            EventBus.getDefault().post(eventBusCarrier);
        }
        }
    }
}

4.添加 （JsBridge：js中调用Android方法的对象名）

webView.addJavascriptInterface(new JavaScriptUtil(), "JsBridge");

5.注入js

   binding.jsWebView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }

            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);
                if (mInjection) {
                    mInjection = false;
                }
            }

            @Override
            public void onLoadResource(WebView view, String url) {
                super.onLoadResource(view, url);
                if (mInjection) {
                    return;
                }
                if (url.endsWith(".js") || url.endsWith(".css")) {  // 如果是注入到本地html中去掉这个判断
                   // 调用注入方法
                    onJsLocal();
                    mInjection = true;
                }
            }
        })；
    }

  @SuppressLint("ObsoleteSdkInt")
    public void onJsLocal() {
        StringBuilder builder = new StringBuilder(JSTools.getJS(this, "test.js"));
        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.KITKAT) {
            binding.jsWebView.loadUrl("javascript:" + builder.toString());
        } else {
            binding.jsWebView.evaluateJavascript(builder.toString(), new ValueCallback<String>() {
                @Override
                public void onReceiveValue(String value) {
                    Log.i("onReceiveValue", value);
                }
            });
        }
    }

6.Android 调用js方法 传值给js
步骤 3 中发送了处理后的消息，在webactivity中接受消息并处理：

    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onHandleEvent(EventBusCarrier busCarrier) {
       if (null != busCarrier) {
            if (TextUtils.equals(busCarrier.getEventType(), "testMethod")) {
                 //....
                // 调用js方法传数据
                onJSCallback(data1, data2);
            }
        }
    }

    /**
     * 执行JS回调，用于关闭web支付对话框
     *
     * @param serialNumber 参数为服务端返回的交易hash
     */
    public void onJSCallback(String data1, String data2) {
        StringBuilder sb = new StringBuilder("callbackResult(\'" + data1+ "\',\'{\"data\":\"");
        sb.append(data2);
        sb.append("\"}\')");
        if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.KITKAT) {
            sb.insert(0, "javascript:");
            binding.jsWebView.loadUrl(sb.toString());
            Log.i("javascript", sb.toString());
        } else {
            binding.jsWebView.evaluateJavascript(sb.toString(), null);
            Log.i("javascript", sb.toString());
        }
    }

数据示例：(参数需要使用单引号包着)
else 中对应的
callbackResult('sr1557665118336','{"data":"test"}')
if中对应的
javascript:callbackResult('sr1557665118336','{"data":"test"}')

7.补充：eventbus 消息实体封装类

public class EventBusCarrier {
    private String eventType; //区分事件的类型
    private Object object;  //事件的实体类

    public String getEventType() {
        return eventType;
    }

    public void setEventType(String eventType) {
        this.eventType = eventType;
    }

    public Object getObject() {
        return object;
    }

    public void setObject(Object object) {
        this.object = object;
    }
}

8.总结：

2.、3 、 4 js 调用Android方法；
5    js文件注入；
6   Android 调用 Js