WebView实现js调用安卓虚拟机的系统相机

package cn.edu.xxxxxx.webkit;

import android.content.Intent;
import android.net.Uri;
import android.os.Handler;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.webkit.JavascriptInterface;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private WebView mWebView;
    private Handler mHandler = new Handler();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mWebView = (WebView) findViewById(R.id.webview);
        mWebView.setVerticalScrollbarOverlay(true);
        final WebSettings webSettings = mWebView.getSettings();
        webSettings.setSupportZoom(true);
        webSettings.setJavaScriptEnabled(true);
        webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        mWebView.addJavascriptInterface(new demo(), "demo");
        mWebView.loadUrl("file:///android_asset/index.html");


        }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if ((keyCode == event.KEYCODE_BACK ) && mWebView.canGoBack()) {
            mWebView.goBack();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
       class demo {
          @JavascriptInterface
           public void back() {

               mHandler.post(new Runnable() {
                   @Override
                   public void run() {

                    /*系统相机的调用

                      */
                       Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                       startActivityForResult(intent, 1);



                   }
               });
            

       }

    }
}

过程介绍：

1.首先，在清单文件中，添加调用系统相机的权限

<!-- 调用摄像头的权限 -->
<uses-permission android:name="android.permission.CAMERA"/>

2.创建布局文件。放置webView控件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="cn.edu.xxxxx.webkit.MainActivity">

    <WebView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/webview"
        />
</LinearLayout>

3.创建一个assets文件夹。（在引用时候要注意路径的写法，

"file:///android_asset/index.html"

）

4、就是对Activity的编写。

通过webView