文件上传Webview

Question

我正在尝试使其可以在Web视图中上传文件（大多数情况下为图像），但是我没有框可以进入文件。...

这是我用于Webview的代码：

公共类MainActivity扩展了AppCompatActivity

    implements NavigationView.OnNavigationItemSelectedListener {

private WebView wv;


setContentView(R.layout.activity_main);
          Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
          setSupportActionBar(toolbar);

          DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
          ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                  this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
          drawer.setDrawerListener(toggle);
          toggle.syncState();

          NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
          navigationView.setNavigationItemSelectedListener(this);

          wv = (WebView) findViewById(R.id.webView1);
          WebSettings settings = wv.getSettings();
          settings.setJavaScriptEnabled(true);
          CookieManager.getInstance().setAcceptCookie(true);
          wv.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
          wv.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
          wv.getSettings().setAppCacheEnabled(false);
          wv.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
          settings.setDomStorageEnabled(false);
          settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
          settings.setUseWideViewPort(true);
          settings.setSavePassword(true);
          settings.setSaveFormData(true);

          wv.loadUrl("http://THELINKTOMYSITE.com");
          wv.setWebViewClient(new MywebViewClient());



          ////////////////////////////
          wv.setWebViewClient(new WebViewClient() {
              public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                  wv.loadUrl("file:///android_asset/error.html");
              }
          });