js與native的交互

時間 2019-12-09

原文原文鏈接

WebView與Javascript交互(Android)：

WebView與Javascript交互是雙向的數據傳遞，1.H5網頁的JS函數調用Native函數 2.Native函數調用JS函數，具體實現如下面例子爲主：javascript

1.）mainfest.xml中加入網絡權限

<uses-permission android:name="android.permission.INTERNET"/>

2.）WebView開啓支持JavaScript

  mWebView.getSettings().setJavaScriptEnabled(true);

3.）簡單的H5網頁實現，主要實現actionFromNative()、actionFromNativeWithParam(String str)，放在assets文件下

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <script type="text/javascript">
    function actionFromNative(){
         document.getElementById("log_msg").innerHTML +=
             "<br\>Native調用了js函數";
    }

    function actionFromNativeWithParam(arg){
         document.getElementById("log_msg").innerHTML +=
             ("<br\>Native調用了js函數並傳遞參數："+arg);
    }

    </script>
</head>
<body>
<p>WebView與Javascript交互</p>
<div>
    <button onClick="window.wx.actionFromJs()">點擊調用Native代碼</button>
</div>
<br/>
<div>
    <button onClick="window.wx.actionFromJsWithParam('come from Js')">點擊調用Native代碼並傳遞參數</button>
</div>
<br/>
<div id="log_msg">調用打印信息</div>
</body>
</html>

4.）Native實現與JS交互函數：actionFromJs()、actionFromJsWithParam()

public class MainActivity extends Activity {
    private WebView mWebView;
    private TextView logTextView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mWebView = (WebView) findViewById(R.id.webview);
        // 啓用javascript
        mWebView.getSettings().setJavaScriptEnabled(true);
        // 從assets目錄下面的加載html
        mWebView.loadUrl("file:///android_asset/wx.html");
        mWebView.addJavascriptInterface(this, "wx");
        logTextView = (TextView) findViewById(R.id.text);
        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View v) {
                // 無參數調用
                mWebView.loadUrl("javascript:actionFromNative()");
                // 傳遞參數調用
                mWebView.loadUrl("javascript:actionFromNativeWithParam(" + "'come from Native'" + ")");
            }
        });

    }

    @android.webkit.JavascriptInterface
    public void actionFromJs() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(MainActivity.this, "js調用了Native函數", Toast.LENGTH_SHORT).show();
                String text = logTextView.getText() + "\njs調用了Native函數";
                logTextView.setText(text);
            }
        });
    }

    @android.webkit.JavascriptInterface
    public void actionFromJsWithParam(final String str) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Toast.makeText(MainActivity.this, "js調用了Native函數傳遞參數：" + str, Toast.LENGTH_SHORT).show();
                String text = logTextView.getText() +  "\njs調用了Native函數傳遞參數：" + str;
                logTextView.setText(text);
            }
        });

    }
}

mWebView.addJavascriptInterface(this, "wx");至關於添加一個js回調接口，而後給這個起一個別名，我這裏起的名字wx（微信哈哈）。@android.webkit.JavascriptInterface爲了解決addJavascriptInterface漏洞的，在4.2之後纔有的。html

5.）佈局文件實現

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">

    <WebView
        android:id="@+id/webview"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

    <TextView android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text=""/>

    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Native調用js函數"/>

</LinearLayout>