【自己研究的】在现有sdk+集成的基础上，增加一个独立Activity的Webview集成

在现在已经集成的基础上，增加一个独立activity的webview，经过测试可行，不过有个问题，就是在这个页面如果调用了拍照或选择照片功能后，原来的集成模式，安卓系统的返回键没有响应了，但其他功能还能正常使用，请问这种做法可取吗？求教。

代码如下：
（1）主程序集成是这样的：
public class DefaultMainActivity extends io.dcloud.PandoraEntry {
。。。。。
}
（2）新增加Activity集成如下：
public class SDKWebViewActivity extends Activity {

boolean doHardAcc = true;  
IWebview webview = null;  

EntryProxy mEntryProxy = null;  

@Override  
public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);  
    requestWindowFeature(Window.FEATURE_NO_TITLE);  
    //直接获取存在的低层EntryProxy  
    mEntryProxy = EntryProxy.getInstnace();  
    mEntryProxy.onCreate(this, savedInstanceState,  
            SDK.IntegratedMode.WEBVIEW, null);  

    final FrameLayout rootView = new FrameLayout(this);  
    setContentView(rootView);  

    rootView.setBackgroundColor(0xffffffff);  
    rootView.getViewTreeObserver().addOnGlobalLayoutListener(  
            new OnGlobalLayoutListener() {  
                @Override  
                public void onGlobalLayout() {  
                    webview.onRootViewGlobalLayout(rootView);  
                }  
            });  

    Bundle bd = this.getIntent().getExtras();  
    String url = bd.getString("url");  
    String appid = UUID.randomUUID().toString();  
    // 单页面集成时要加载页面的路径，可以是本地文件路径也可以是网络路径  
    String localUrl = "file:///android_asset/apps/AppECMS/www/";  
    String viewUrl = "";  

    if (!url.startsWith("http://")) {  
        viewUrl = localUrl + url;  
    } else {  
        viewUrl = url;  
    }  
    webview = SDK.createWebview(this, viewUrl, appid,  
            new IWebviewStateListener() {  
                @Override  
                public Object onCallBack(int pType, Object pArgs) {  
                    switch (pType) {  
                    case IWebviewStateListener.ON_WEBVIEW_READY:  
                        // 准备完毕之后添加webview到显示父View中，设置排版不显示状态，避免显示webview时，html内容排版错乱问题  
                        ((IWebview) pArgs).obtainFrameView()  
                                .obtainMainView()  
                                .setVisibility(View.INVISIBLE);  
                        SDK.attach(rootView, ((IWebview) pArgs));  
                        break;  
                    case IWebviewStateListener.ON_PAGE_STARTED:  
                        // 首页面开始加载事件  
                        break;  
                    case IWebviewStateListener.ON_PROGRESS_CHANGED:  
                        // 首页面加载进度变化  
                        break;  
                    case IWebviewStateListener.ON_PAGE_FINISHED:  
                        // 页面加载完毕，设置显示webview  
                        webview.obtainFrameView().obtainMainView()  
                                .setVisibility(View.VISIBLE);  
                        break;  
                    }  
                    return null;  
                }  
            });  

    final WebView webviewInstance = webview.obtainWebview();  
    // 添加自定义JS交互对象  
    webviewInstance.addJavascriptInterface(new EcmsPlusImpl(this),  
            "EcmsPlus");  
    // 监听返回键  
    webviewInstance.setOnKeyListener(new OnKeyListener() {  
        @Override  
        public boolean onKey(View v, int keyCode, KeyEvent event) {  
            if (keyCode == KeyEvent.KEYCODE_BACK) {  
                if (webviewInstance.canGoBack()) {  
                    webviewInstance.goBack();  
                    return true;  
                } else {  
                    SDKWebViewActivity.this.finish();  
                }  
            }  
            return false;  
        }  
    });  

}  

@Override  
public boolean onCreateOptionsMenu(Menu menu) {  
    return mEntryProxy.onActivityExecute(this,  
            SysEventType.onCreateOptionMenu, menu);  
}  

@Override  
public void onPause() {  
    super.onPause();  
    mEntryProxy.onPause(this);  
}  

@Override  
public void onResume() {  
    super.onResume();  
    mEntryProxy.onResume(this);  
}  

public void onNewIntent(Intent intent) {  
    super.onNewIntent(intent);  
    if (intent.getFlags() != 0x10600000) {// 非点击icon调用activity时才调用newintent事件  
        mEntryProxy.onNewIntent(this, intent);  
    }  
}  

@Override  
protected void onDestroy() {  
    super.onDestroy();  
    mEntryProxy.destroy(this);  
}  

@Override  
public boolean onKeyDown(int keyCode, KeyEvent event) {  
    boolean _ret = mEntryProxy.onActivityExecute(this,  
            SysEventType.onKeyDown, new Object[] { keyCode, event });  
    return _ret ? _ret : super.onKeyDown(keyCode, event);  
}  

@Override  
public boolean onKeyUp(int keyCode, KeyEvent event) {  
    boolean _ret = mEntryProxy.onActivityExecute(this,  
            SysEventType.onKeyUp, new Object[] { keyCode, event });  
    return _ret ? _ret : super.onKeyUp(keyCode, event);  
}  

@Override  
public boolean onKeyLongPress(int keyCode, KeyEvent event) {  
    boolean _ret = mEntryProxy.onActivityExecute(this,  
            SysEventType.onKeyLongPress, new Object[] { keyCode, event });  
    return _ret ? _ret : super.onKeyLongPress(keyCode, event);  
}  

public void onConfigurationChanged(Configuration newConfig) {  
    try {  
        int temp = this.getResources().getConfiguration().orientation;  
        if (mEntryProxy != null) {  
            mEntryProxy.onConfigurationChanged(this, temp);  
        }  
        super.onConfigurationChanged(newConfig);  
    } catch (Exception e) {  
        e.printStackTrace();  
    }  
}  

protected void onActivityResult(int requestCode, int resultCode, Intent data) {  
    mEntryProxy.onActivityExecute(this, SysEventType.onActivityResult,  
            new Object[] { requestCode, resultCode, data });  
}  

}