com.google.gwt.sample.showcase.client.content.widgets.CwFileUpload.java Source code

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Here is the source code for com.google.gwt.sample.showcase.client.content.widgets.CwFileUpload.java

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/*
 * Copyright 2008 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.sample.showcase.client.content.widgets;

import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.RunAsyncCallback;
import com.google.gwt.i18n.client.Constants;
import com.google.gwt.sample.showcase.client.ContentWidget;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseData;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseSource;
import com.google.gwt.sample.showcase.client.ShowcaseAnnotations.ShowcaseStyle;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.user.client.ui.FileUpload;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * Example file.
 */
@ShowcaseStyle(".gwt-FileUpload")
public class CwFileUpload extends ContentWidget {
    /**
     * The constants used in this Content Widget.
     */
    @ShowcaseSource
    public static interface CwConstants extends Constants {
        String cwFileUploadButton();

        String cwFileUploadDescription();

        String cwFileUploadName();

        String cwFileUploadNoFileError();

        String cwFileUploadSelectFile();

        String cwFileUploadSuccessful();
    }

    /**
     * An instance of the constants.
     */
    @ShowcaseData
    private final CwConstants constants;

    /**
     * Constructor.
     *
     * @param constants the constants
     */
    public CwFileUpload(CwConstants constants) {
        super(constants.cwFileUploadName(), constants.cwFileUploadDescription(), true);
        this.constants = constants;
    }

    /**
     * Initialize this example.
     */
    @ShowcaseSource
    @Override
    public Widget onInitialize() {
        // Create a vertical panel to align the content
        VerticalPanel vPanel = new VerticalPanel();

        // Add a label
        vPanel.add(new HTML(constants.cwFileUploadSelectFile()));

        // Add a file upload widget
        final FileUpload fileUpload = new FileUpload();
        fileUpload.ensureDebugId("cwFileUpload");
        vPanel.add(fileUpload);

        // Add a button to upload the file
        Button uploadButton = new Button(constants.cwFileUploadButton());
        uploadButton.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent event) {
                String filename = fileUpload.getFilename();
                if (filename.length() == 0) {
                    Window.alert(constants.cwFileUploadNoFileError());
                } else {
                    Window.alert(constants.cwFileUploadSuccessful());
                }
            }
        });
        vPanel.add(new HTML("<br>"));
        vPanel.add(uploadButton);

        // Return the layout panel
        return vPanel;
    }

    @Override
    protected void asyncOnInitialize(final AsyncCallback<Widget> callback) {
        GWT.runAsync(CwFileUpload.class, new RunAsyncCallback() {

            public void onFailure(Throwable caught) {
                callback.onFailure(caught);
            }

            public void onSuccess() {
                callback.onSuccess(onInitialize());
            }
        });
    }
}