java将数据从活动传递到在同一活动中webView加载的HTML文件中使用的JavaScript

11 月，1 周 Questions & Answers 7785

我的Android应用程序的目标是扫描条形码/二维码，并将其传递到webView元素中加载的HTML文件

该应用程序只有一个布局，其中包含一个按钮和webview元素。单击按钮后，应用程序将打开bar/QR扫描仪并将结果返回到活动，我需要将此结果传递到我的HTML文件以进行进一步处理

MainActivity工作正常，如this教程中所示，并在此处返回结果：

    public void onActivityResult(int requestCode, int resultCode, Intent intent) {

    IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
    if (scanningResult != null) {
        String scanContent = scanningResult.getContents();
        String scanFormat = scanningResult.getFormatName();
        formatTxt.setText("FORMAT: " + scanFormat);
        contentTxt.setText("CONTENT: " + scanContent);

     /*** I NEED to SEND the 'scanContent' to the my HTML file loaded at the WebView element   ***/

    }
    else{
        Toast toast = Toast.makeText(getApplicationContext(),
                "No scan data received!", Toast.LENGTH_SHORT);
        toast.show();
    }
}

我阅读了this和this和this和this和this并得到以下文件：

JavaScriptInterface。爪哇

 public class JavaScriptInterface {
    Context mContext;

    /** Instantiate the interface and set the context */
    JavaScriptInterface(Context c) {
        mContext = c;
    }

    /** Show a toast from the web page */
    @JavascriptInterface
    public void showToast(String toast) {
        Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
    }

}

以及WebViewActivity。爪哇：

public class WebViewActivity extends Activity {

// private WebView webView;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    WebView webView = (WebView)findViewById(R.id.webview);

    webView.getSettings().setJavaScriptEnabled(true);
    webView.addJavascriptInterface(new JavaScriptInterface(this), "Android");

   /*** I think something wrong in this area **/

    webView.loadUrl("file:///安卓_asset/myFile.html");
    webView.setWebViewClient(new WebViewClient(){
        public void onPageFinished(WebView view, String url){
            view.loadUrl("javascript:init('" + url + "')");
        }
    });

    //webView.loadUrl("http://www.google.com");

    // String customHtml = "<html><body>" +
    //        ""+
    //        "</body></html>";
    // webView.loadData(customHtml, "text/html", "UTF-8");

}

}

Android Studio IDE中没有出现错误，在运行应用程序时，按下按钮进行扫描，但webview中没有显示任何内容，只有白色页面！！白色页面总是，从启动到启动，再扫描代码

知道我在哪里迷路了吗？知道怎么修吗

注意在同一活动中，我需要将数据发送到webView加载的HTML文件中使用的JavaScript，而不仅仅是发送要加载的URL

Tags:

共 (2) 个答案

# 1 楼答案

对于发送部分，将其放在MainActivity中，输入您想要输入的值，如下所示：

Intent sendIntent = new Intent(this, WebViewActivity.class);
sendIntent.putExtra("webBrowserUrl", "http://www.google.com");
//add other values to intent as necessary
startActivity(sendIntent);

然后在您的WebViewActivity中，在调用super之后执行此操作以获取数据。onCreate（）：

String url = getIntent().getStringExtra("webBrowserUrl");
webView.loadUrl(url);

# 2 楼答案

在阅读了this和this和this之后，我发现我的情况可以总结如下：

在Android应用程序中将变量从类传递到另一个类（即Java类）
从WebView加载的HTML文件中的JavaScript调用Android函数
将参数从Android类发送回JavaScript

因此，解决方案可以总结如下：

创建可以与JavaScript命令交互的JavaScriptInterface类
在与JavaScript交互所需的每个函数之前使用@JavascriptInterface注释
将要在JavaScript文件中用作module的JavaScript交互的名称定义为：myWebView.addJavascriptInterface(new JavaScriptInterface(this), "module");在该语句中，module是要在JavaScript文件中作为module.function()调用的名称模块
使用getter和setter在Android类之间进行通信

我的MainActivity.java文件变成这样：

package com.fonix.qr;

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements OnClickListener {

private Button scanBtn;
private TextView formatTxt, contentTxt;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    scanBtn = (Button) findViewById(R.id.scan_button);
    formatTxt = (TextView) findViewById(R.id.scan_format);
    contentTxt = (TextView) findViewById(R.id.scan_content);
    scanBtn.setOnClickListener(this);

    WebView myWebView = (WebView) findViewById(R.id.webview);
    myWebView.setWebViewClient(new WebViewClient());

    myWebView.addJavascriptInterface(new JavaScriptInterface(this), "fonix");
    WebSettings webSettings = myWebView.getSettings();

    webSettings.setJavaScriptEnabled(true);
    myWebView.loadUrl("file:///android_asset/index.html");
}

public void onClick(View v) {
    if (v.getId() == R.id.scan_button) {
        scanCode();
      //  IntentIntegrator scanIntegrator = new IntentIntegrator(this);
      //  scanIntegrator.initiateScan();
    }
}
public void scanCode(){
    IntentIntegrator scanIntegrator = new IntentIntegrator(this);
    scanIntegrator.initiateScan();
    }

public String scanContent;
public String scanFormat;
public void onActivityResult(int requestCode, int resultCode, Intent intent) {

    IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
    if (scanningResult != null) {
        scanContent = scanningResult.getContents();
        scanFormat = scanningResult.getFormatName();
        formatTxt.setText("FORMAT: " + scanFormat);
        contentTxt.setText("CONTENT: " + scanContent);
    } else {
        Toast toast = Toast.makeText(getApplicationContext(),
                "No scan data received!", Toast.LENGTH_SHORT);
        toast.show();
    }

}
public String getContent(){ return scanContent; }

public class JavaScriptInterface {
    Context mContext;

    /* Instantiate the interface and set the context */
    JavaScriptInterface(Context c) {
        mContext = c;
    }

    /* Show a toast from the web page */
    @JavascriptInterface
    public void showToast(String toast) {
        Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
    }

    @JavascriptInterface
    public void scanJS() {
        scanCode();
    }

    @JavascriptInterface
    public String scanResult() {
         return getContent();
    }
  }
}

并且assets -> index.html文件是：

<!DOCTYPE html>
<html>
<head>
   <title>QR and BarCode Scanner using both Android Native and JavaScript Functionality</title>
</head>

<body>
   Hello Android! <br/>
     <br/>
  The above button in Native Android, while the below one is JavaScript button. <br/>
    <br/>
<input type="button" value="Scan from JavaScript button" onClick="scan()" />
    <br/>
    <br/>
    <br/>
 Below button will show the latest scan result, regardless read through Native Android button, or JavaScript button, and will display the result as Native Android Toast.
   <br/>
   <br/>
  <input type="button" value="Show Scan result" onClick="showScanResult()" />
 </body>

 <script type="text/javascript">
    function scan() {
       fonix.scanJS();
    }

    function showScanResult() {
        var scanResult = fonix.scanResult();
        // (!scanResult) equal === null or === undefined
        if(!scanResult)fonix.showToast("Nothing had been scanned");
           else fonix.showToast(fonix.scanResult());
    }
 </script>
</html>

layout -> activity_main.xml文件是：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.fonix.qr.MainActivity">

<Button android:id="@+id/scan_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/scan"
    android:layout_alignParentTop="true"
    android:layout_alignParentStart="true" />

<TextView
    android:id="@+id/scan_format"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textIsSelectable="true"
    android:layout_below="@id/scan_button"
    android:layout_alignEnd="@+id/scan_button" />
<TextView
    android:id="@+id/scan_content"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textIsSelectable="true"
    android:layout_below="@+id/scan_format"
    android:layout_alignEnd="@+id/webview" />

<WebView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/webview"
    android:layout_alignParentStart="true"
    android:layout_alignParentBottom="true"
    android:layout_alignParentEnd="true"
    android:layout_below="@+id/scan_content" />
  </RelativeLayout>

values -> strings.xml文件是：

<resources>
   <string name="app_name">QR and BarCode reader</string>
   <string name="scan">Scan from Native Android button</string>
</resources>

AndroidManifest.xml文件是：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.fonix.qr">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />

</manifest>

最终的应用程序结构是：

读的时候

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java将数据从活动传递到在同一活动中webView加载的HTML文件中使用的JavaScript

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# 1 楼答案

# 2 楼答案