Add Undo/Redo fucntions

app/src/main/java/com/pileproject/drive/programming/visual/activity/ProgrammingActivityBase.java

@@ -59,6 +59,7 @@ public abstract class ProgrammingActivityBase extends AppCompatActivity {
     private final String TAG = "NxtProgrammingActivity";
     private List<Button> mAddBlockButtons;
     private Button mExecButton;
+    private UndoAndRedoButtonsManager mButtonsManager;
     private ProgrammingSpaceManager mSpaceManager;
     private boolean mIsConnected = false;
 
@@ -108,8 +109,11 @@ protected void onPostCreate(Bundle savedInstanceState) {
     protected abstract Intent getIntentToExecute();
 
     private void findViews() {
+        mButtonsManager = new UndoAndRedoButtonsManager((Button) findViewById(R.id.programming_undoButton),
+                                                        (Button) findViewById(R.id.programming_redoButton));
         mSpaceManager = new ProgrammingSpaceManager(this,
-                                                    (BlockSpaceLayout) findViewById(R.id.programming_placingBlockSpaceLayout));
+                                                    (BlockSpaceLayout) findViewById(R.id.programming_placingBlockSpaceLayout),
+                                                    mButtonsManager);
         mAddBlockButtons = new ArrayList<>(NKINDS);
         mAddBlockButtons.add((Button) findViewById(R.id.programming_sequenceButton));
         mAddBlockButtons.add((Button) findViewById(R.id.programming_repetitionButton));
@@ -160,6 +164,7 @@ protected void onActivityResult(
                     String blockName = data.getStringExtra("block_name");
                     ArrayList<BlockBase> blocks = BlockFactory.createBlocks(howToMake, blockName);
                     mSpaceManager.addBlocks(blocks);
+                    mButtonsManager.checkButtonsWorkability();
                 }
                 break;
 
@@ -250,6 +255,7 @@ private void onDeleteAllBlocks() {
                                        @Override
                                        public void onClick(DialogInterface dialog, int which) {
                                            mSpaceManager.deleteAllBlocks();
+                                           mButtonsManager.checkButtonsWorkability();
                                        }
                                    })
                 .setNegativeButton(R.string.cancel, null)
@@ -348,4 +354,44 @@ public String getInputtedProgramName() {
             return mEditText.getText().toString();
         }
     }
+
+    /**
+     * The manager of Undo and Redo buttons.
+     * This check the workability of buttons and
+     * enable or disable them.
+     *
+     * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+     */
+    public class UndoAndRedoButtonsManager {
+        private Button mUndoButton;
+        private Button mRedoButton;
+
+        public UndoAndRedoButtonsManager(Button undoButton, Button redoButton) {
+            mUndoButton = undoButton;
+            mRedoButton = redoButton;
+
+            mUndoButton.setEnabled(false);
+            mUndoButton.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    mSpaceManager.undo();
+                    checkButtonsWorkability();
+                }
+            });
+
+            mRedoButton.setEnabled(false);
+            mRedoButton.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    mSpaceManager.redo();
+                    checkButtonsWorkability();
+                }
+            });
+        }
+
+        public void checkButtonsWorkability() {
+            mUndoButton.setEnabled(mSpaceManager.canUndo());
+            mRedoButton.setEnabled(mSpaceManager.canRedo());
+        }
+    }
 }

app/src/main/java/com/pileproject/drive/programming/visual/event/AddEvent.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2011-2015 PILE Project, Inc. <dev@pileproject.com>
+ *
+ * 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.pileproject.drive.programming.visual.event;
+
+
+import com.pileproject.drive.programming.visual.block.BlockBase;
+import com.pileproject.drive.programming.visual.layout.BlockSpaceLayout;
+
+/**
+ * EventBase for the addition of block
+ *
+ * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+ * @version 1.0 4-June-2013
+ */
+public class AddEvent extends EventBase {
+
+    public AddEvent(int elementCount, int index) {
+        super(elementCount, index);
+    }
+
+    @Override
+    public EventBase undo(BlockSpaceLayout layout, int elementCount) {
+        // Get block name
+        String blockName = ((BlockBase) layout.getChildAt(mIndex)).getClass().getName();
+        layout.removeViewAt(mIndex); // Remove it
+
+        // Create a new DeleteNumDiff for Redo
+        EventBase diffForRedo = new DeleteEvent(elementCount, mIndex, blockName);
+        return diffForRedo;
+    }
+}

app/src/main/java/com/pileproject/drive/programming/visual/event/ChangeNumberEvent.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011-2015 PILE Project, Inc. <dev@pileproject.com>
+ *
+ * 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.pileproject.drive.programming.visual.event;
+
+import com.pileproject.drive.programming.visual.block.BlockBase;
+import com.pileproject.drive.programming.visual.block.NumTextHolder;
+import com.pileproject.drive.programming.visual.layout.BlockSpaceLayout;
+
+/**
+ * EventBase for the number change of TextView attached to block
+ *
+ * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+ * @version 1.0 4-June-2013
+ */
+public class ChangeNumberEvent extends EventBase {
+    private int mOldNum;
+
+    public ChangeNumberEvent(int elementCount, int index, int oldNum) {
+        super(elementCount, index);
+
+        mOldNum = oldNum;
+    }
+
+    @Override
+    public EventBase undo(BlockSpaceLayout layout, int elementCount) {
+        BlockBase block = (BlockBase) layout.getChildAt(mIndex);
+
+        // Get current number of TextView
+        int curNum = ((NumTextHolder) block).getNum();
+        ((NumTextHolder) block).setNum(mOldNum); // Set old number to TextView
+
+        // Create a new ChangeNumberEvent for Redo
+        EventBase diffForRedo = new ChangeNumberEvent(elementCount, mIndex, curNum);
+
+        return diffForRedo;
+    }
+}

app/src/main/java/com/pileproject/drive/programming/visual/event/DeleteEvent.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2011-2015 PILE Project, Inc. <dev@pileproject.com>
+ *
+ * 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.pileproject.drive.programming.visual.event;
+
+import android.view.ViewGroup;
+
+import com.pileproject.drive.programming.visual.block.BlockBase;
+import com.pileproject.drive.programming.visual.block.BlockFactory;
+import com.pileproject.drive.programming.visual.layout.BlockSpaceLayout;
+
+/**
+ * EventBase for the delete of a block
+ *
+ * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+ * @version 1.0 4-June-2013
+ */
+public class DeleteEvent extends EventBase {
+    private String mBlockName;
+
+    public DeleteEvent(int elementCount, int index, String name) {
+        super(elementCount, index);
+
+        mBlockName = name;
+    }
+
+    @Override
+    public EventBase undo(BlockSpaceLayout layout, int elementCount) {
+        // Recreate block
+        BlockBase block = BlockFactory.createBlocks(BlockFactory.UNDO, mBlockName).get(0);
+
+        // Attach it to layout
+        layout.addView(block, mIndex,
+                       new BlockSpaceLayout.LayoutParams(
+                               ViewGroup.LayoutParams.WRAP_CONTENT,
+                               ViewGroup.LayoutParams.WRAP_CONTENT));
+
+        // Create a new AddNumDiff for Redo
+        EventBase diffForRedo = new AddEvent(elementCount, mIndex);
+        return diffForRedo;
+    }
+}

app/src/main/java/com/pileproject/drive/programming/visual/event/EventBase.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2011-2015 PILE Project, Inc. <dev@pileproject.com>
+ *
+ * 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.pileproject.drive.programming.visual.event;
+
+
+import com.pileproject.drive.programming.visual.layout.BlockSpaceLayout;
+
+/**
+ * Base class of EventBase for undo and redo
+ *
+ * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+ * @version 1.0 4-June-2013
+ */
+public abstract class EventBase {
+    protected final int mElementCount;
+    protected final int mIndex;
+
+    protected EventBase(int elementCount, int index) {
+        mElementCount = elementCount;
+        mIndex = index;
+    }
+
+    public int getElementCount() {
+        return mElementCount;
+    }
+
+    public int getIndex() {
+        return mIndex;
+    }
+
+    /**
+     * Undo method
+     *
+     * @param layout       Layout that has blocks
+     * @param elementCount Number that shows how many UNDOs should be done at once
+     * @return
+     */
+    public abstract EventBase undo(BlockSpaceLayout layout, int elementCount);
+}

app/src/main/java/com/pileproject/drive/programming/visual/event/MoveEvent.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2011-2015 PILE Project, Inc. <dev@pileproject.com>
+ *
+ * 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.pileproject.drive.programming.visual.event;
+
+import android.view.View;
+
+import com.pileproject.drive.programming.visual.layout.BlockSpaceLayout;
+
+
+/**
+ * EventBase for the move of block
+ *
+ * @author <a href="mailto:tatsuyaw0c@gmail.com">Tatsuya Iwanari</a>
+ * @version 1.0 4-June-2013
+ */
+public class MoveEvent extends EventBase {
+    private int mOldX, mOldY;
+
+    public MoveEvent(int elementCount, int index, int oldX, int oldY) {
+        super(elementCount, index);
+        mOldX = oldX;
+        mOldY = oldY;
+    }
+
+    @Override
+    public EventBase undo(BlockSpaceLayout layout, int elementCount) {
+        View view = layout.getChildAt(mIndex); // Get view
+
+        // Get current position of View and move
+        int curX = view.getLeft();
+        int curY = view.getTop();
+        view.layout(mOldX, mOldY, mOldX + view.getWidth(), mOldY + view.getHeight());
+
+        // Create New MoveEvent for Redo
+        EventBase diffForRedo = new MoveEvent(elementCount, mIndex, curX, curY);
+
+        return diffForRedo;
+    }
+}