Add Drag and Drop states to RootList.
Also, changed Drag Shadow to 100% opaque.
Bug: 32772075
Change-Id: I8629e4c1caed3cef6460866e5fd39f14801ccbb4
diff --git a/src/com/android/documentsui/DragAndDropHelper.java b/src/com/android/documentsui/DragAndDropHelper.java
new file mode 100644
index 0000000..1b634c3
--- /dev/null
+++ b/src/com/android/documentsui/DragAndDropHelper.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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.android.documentsui;
+
+import static com.android.documentsui.base.Shared.DEBUG;
+
+import android.util.Log;
+
+import com.android.documentsui.base.DocumentInfo;
+
+import java.util.List;
+
+/**
+ * A helper class for drag and drop operations
+ */
+public final class DragAndDropHelper {
+
+ private static final String TAG = "DragAndDropHelper";
+
+ private DragAndDropHelper() {}
+
+ /**
+ * Helper method to see whether an item can be dropped/copied into a particular destination.
+ * Don't copy from the cwd into a provided list of prohibited directories. (ie. into cwd, into a
+ * selected directory). Note: this currently doesn't work for multi-window drag, because
+ * localState isn't carried over from one process to another.
+ */
+ public static boolean canCopyTo(Object dragLocalState, DocumentInfo dst) {
+ if (dragLocalState == null || !(dragLocalState instanceof List<?>)) {
+ if (DEBUG) Log.d(TAG, "Invalid local state object. Will allow copy.");
+ return true;
+ }
+ List<?> src = (List<?>) dragLocalState;
+ if (src.contains(dst)) {
+ if (DEBUG) Log.d(TAG, "Drop target same as source. Ignoring.");
+ return false;
+ }
+ return true;
+ }
+}