Android 如何使用webview从手机存储器中读取本地html文件？

我需要制作一个apk文件，其中webview将加载一个html5文件，该文件不在assets文件夹中。html5文件位于手机存储器中。这是我的密码

private WebView web;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    web = (WebView) findViewById(R.id.webV);
    web.setWebViewClient(new myWebClient());
    web.getSettings().setJavaScriptEnabled(true);
    web.getSettings().setLoadWithOverviewMode(true);
    web.getSettings().setUseWideViewPort(true);
    String url = "file:///" + Environment.getExternalStorageDirectory().toString() + File.separator + "Download/index.html";
    web.loadUrl(url);
}

public class myWebClient extends WebViewClient
{
     @Override
     public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
         handler.proceed(); // Ignore SSL certificate errors
     }

    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
        // TODO Auto-generated method stub
        super.onPageStarted(view, url, favicon);
    }

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        // TODO Auto-generated method stub

        view.loadUrl(url);
        return true;

    }
}

// To handle "Back" key press event for WebView to go back to previous screen.
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) 
{
    if ((keyCode == KeyEvent.KEYCODE_BACK) && web.canGoBack()) {
        web.goBack();
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

它不读取我在代码中指示的路径。你能告诉我怎么了吗

---

谢谢。

如果（！Environment.getExternalStorageState（）.equals（Environment.MEDIA_-MOUNTED））{Log.d（标记，“无SD卡”）；}或者{web.loadUrl（“文件：//“+Environment.getExternalStorageDirectory（）+”/Download/index.html”）；}请确保您的文件在指定路径中可用。