/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
*
* 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.android.ide.eclipse.adt.internal.editors.layout.gle2;
import com.android.ide.eclipse.adt.internal.editors.descriptors.ElementDescriptor;
import com.android.ide.eclipse.adt.internal.editors.layout.descriptors.ViewElementDescriptor;
import org.eclipse.swt.dnd.ByteArrayTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.dnd.TransferData;
import java.io.UnsupportedEncodingException;
/**
* A d'n'd {@link Transfer} class that can transfer a <em>single</em> {@link ElementDescriptor}.
* <p/>
* The implementation is based on the {@link ByteArrayTransfer} and what we transfer
* is actually only the inner XML name of the element, which is unique enough.
* <p/>
* Drag source provides an {@link ElementDescriptor} object.
* Drog receivers get back a {@link String} object representing the
* {@link ElementDescriptor#getXmlName()}.
* <p/>
* Drop receivers can find the corresponding element by using
* {@link ElementDescriptor#findChildrenDescriptor(String, boolean)} with the
* XML name returned by this transfer operation and their root descriptor.
* <p/>
* Drop receivers must deal with the fact that this XML name may not exist in their
* own {@link ElementDescriptor} hierarchy -- e.g. if the drag came from a different
* GLE based on a different SDK platform or using custom widgets. In this case they
* must refuse the drop.
*/
public class ElementDescTransfer extends ByteArrayTransfer {
// Reference: http://www.eclipse.org/articles/Article-SWT-DND/DND-in-SWT.html
private static final String TYPE_NAME = "android.ADT.element.desc.transfer.1";
private static final int TYPE_ID = registerType(TYPE_NAME);
private static ElementDescTransfer sInstance = new ElementDescTransfer();
private ElementDescTransfer() {
// pass
}
public static ElementDescTransfer getInstance() {
return sInstance;
}
@Override
protected int[] getTypeIds() {
return new int[] { TYPE_ID };
}
@Override
protected String[] getTypeNames() {
return new String[] { TYPE_NAME };
}
@Override
protected void javaToNative(Object object, TransferData transferData) {
if (object == null || !(object instanceof ElementDescriptor)) {
return;
}
if (isSupportedType(transferData)) {
String data = null;
ElementDescriptor desc = (ElementDescriptor)object;
if (desc instanceof ViewElementDescriptor) {
data = ((ViewElementDescriptor) desc).getFullClassName();
} else if (desc != null) {
data = desc.getXmlName();
}
if (data != null) {
try {
byte[] buf = data.getBytes("UTF-8"); //$NON-NLS-1$
super.javaToNative(buf, transferData);
} catch (UnsupportedEncodingException e) {
// unlikely; ignore
}
}
}
}
@Override
protected Object nativeToJava(TransferData transferData) {
if (isSupportedType(transferData)) {
byte[] buf = (byte[]) super.nativeToJava(transferData);
if (buf != null && buf.length > 0) {
try {
String s = new String(buf, "UTF-8"); //$NON-NLS-1$
return s;
} catch (UnsupportedEncodingException e) {
// unlikely to happen, but still possible
}
}
}
return null;
}
}