我正在使用一个显示WebView的非常简单的活动，但是当我从Web视图返回上一个活动时，会出现一个白色屏幕，我需要再按一次后退键才能成功 . 有办法防止这种情况吗？

Web活动Display_web.java：

public class Display_web extends Activity {
    private WebView myWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Intent intent = getIntent();
        String refOeuvre = intent.getStringExtra("REFOEUVRE");
        setContentView(R.layout.display_web);

        myWebView = (WebView) findViewById(R.id.webview);
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        webSettings.setDomStorageEnabled(true);
        myWebView.loadUrl(refOeuvre);
    }

    @Override
    public void onBackPressed() {
        if(myWebView!=null && myWebView.canGoBack())
            myWebView.goBack();// if there is previous page open it
        else
            super.onBackPressed();//if there is no previous page, close app
    }
}

xml文件display_web.xml：

<?xml version="1.0" encoding="utf-8"?>
<WebView  xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/webview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

我使用WebView和ListView调用新WebView的活动：

public class Display_alpha3 extends Activity {
    public ListView mListOeuvres;
    public WebView wikipediaCompo;
    ......
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.display_alpha3);
        Intent intent = getIntent();
        ......
        mListOeuvres = (ListView) findViewById(R.id.list_oeuvres);

        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(Display_alpha3.this,
                android.R.layout.simple_list_item_1, infoOeuvres);

        wikipediaCompo = (WebView) findViewById(R.id.wikipediaCompo);
        WebSettings.setJavaScriptEnabled(true);
        webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
        webSettings.setDomStorageEnabled(true);
        wikipediaCompo.loadUrl(refCompo);
        wikipediaCompo.setWebViewClient(new WebViewClient()
        {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url)
            {
                return false;
            }
        });

        mListOeuvres.setAdapter(adapter);
        mListOeuvres.setOnItemClickListener(new AdapterView.OnItemClickListener(){
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                String pos = String.valueOf(parent.getItemAtPosition(position));
                Intent i = new Intent(Display_alpha3.this, Display_web.class);
                i.putExtra("REFOEUVRE", refYouTube[position]);
                startActivity(i);
            }
        });
    }
}
android webview