4.4(api-19)把下面这个方法给hide了

   /**
     * Tell the client to open a file chooser.
     * @param uploadFile A ValueCallback to set the URI of the file to upload.
     *      onReceiveValue must be called to wake up the thread.a
     * @param acceptType The value of the 'accept' attribute of the input tag
     *         associated with this file picker.
     * @param capture The value of the 'capture' attribute of the input tag
     *         associated with this file picker.
     * @hide
     */
    public void openFileChooser(ValueCallback<Uri> uploadFile, String acceptType, String capture) {
        uploadFile.onReceiveValue(null);
    }

但是直到5.0（api-21）才提供下面这个替代方法

  /**
     * Tell the client to show a file chooser.
     *
     * This is called to handle HTML forms with 'file' input type, in response to the
     * user pressing the "Select File" button.
     * To cancel the request, call <code>filePathCallback.onReceiveValue(null)</code> and
     * return true.
     *
     * @param webView The WebView instance that is initiating the request.
     * @param filePathCallback Invoke this callback to supply the list of paths to files to upload,
     *                         or NULL to cancel. Must only be called if the
     *                         <code>showFileChooser</code> implementations returns true.
     * @param fileChooserParams Describes the mode of file chooser to be opened, and options to be
     *                          used with it.
     * @return true if filePathCallback will be invoked, false to use default handling.
     *
     * @see FileChooserParams
     */
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback,
            FileChooserParams fileChooserParams) {
        return false;
    }

中间4.4 4.4w留下了一个真空期。。。

忒不靠谱。。。

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好吧，决定以后做安卓开发最低只支持到5.0了