Android 解决WebView无法上传文件的问题

 private ValueCallback<Uri[]> uploadMessageAboveL;
  private final static int FILE_CHOOSER_RESULT_CODE = 10000;
  private ValueCallback<Uri> uploadMessage;

  private void openImageChooserActivity() {
    Intent i = new Intent(Intent.ACTION_GET_CONTENT);
    i.addCategory(Intent.CATEGORY_OPENABLE);
    i.setType("image/*");
    startActivityForResult(Intent.createChooser(i, "Image Chooser"), FILE_CHOOSER_RESULT_CODE);
  }


  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == FILE_CHOOSER_RESULT_CODE) {
      if (null == uploadMessage && null == uploadMessageAboveL) return;
      Uri result = data == null || resultCode != RESULT_OK ? null : data.getData();
      if (uploadMessageAboveL != null) {
        onActivityResultAboveL(requestCode, resultCode, data);
      } else if (uploadMessage != null) {
        uploadMessage.onReceiveValue(result);
        uploadMessage = null;
      }
    }
  }


  @TargetApi(Build.VERSION_CODES.LOLLIPOP)
  private void onActivityResultAboveL(int requestCode, int resultCode, Intent intent) {
    if (requestCode != FILE_CHOOSER_RESULT_CODE || uploadMessageAboveL == null)
      return;
    Uri[] results = null;
    if (resultCode == Activity.RESULT_OK) {
      if (intent != null) {
        String dataString = intent.getDataString();
        ClipData clipData = intent.getClipData();
        if (clipData != null) {
          results = new Uri[clipData.getItemCount()];
          for (int i = 0; i < clipData.getItemCount(); i++) {
            ClipData.Item item = clipData.getItemAt(i);
            results[i] = item.getUri();
          }
        }
        if (dataString != null)
          results = new Uri[]{Uri.parse(dataString)};
      }
    }
    uploadMessageAboveL.onReceiveValue(results);
    uploadMessageAboveL = null;
  }

 // For Android < 3.0
    public void openFileChooser(ValueCallback<Uri> valueCallback) {
      uploadMessage = valueCallback;
      openImageChooserActivity();
    }

    // For Android >= 3.0
    public void openFileChooser(ValueCallback valueCallback, String acceptType) {
      uploadMessage = valueCallback;
      openImageChooserActivity();
    }

    //For Android >= 4.1
    public void openFileChooser(ValueCallback<Uri> valueCallback, String acceptType, String capture) {
      uploadMessage = valueCallback;
      openImageChooserActivity();
    }

    // For Android >= 5.0
    @Override
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback, WebChromeClient.FileChooserParams fileChooserParams) {
      uploadMessageAboveL = filePathCallback;
      openImageChooserActivity();
      return true;
    }