Adding a view to indicate space blocked by QSB when QSB is hidden

Change-Id: Ifc6b1f2a7312e7919582887ea67bfe900668b70f
diff --git a/res/layout/qsb_blocker_view.xml b/res/layout/qsb_blocker_view.xml
new file mode 100644
index 0000000..58a148e
--- /dev/null
+++ b/res/layout/qsb_blocker_view.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     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.
+-->
+<com.android.launcher3.QsbBlockerView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />
\ No newline at end of file
diff --git a/src/com/android/launcher3/QsbBlockerView.java b/src/com/android/launcher3/QsbBlockerView.java
new file mode 100644
index 0000000..6a2bce0
--- /dev/null
+++ b/src/com/android/launcher3/QsbBlockerView.java
@@ -0,0 +1,90 @@
+/*
+ * 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.launcher3;
+
+import android.animation.AnimatorSet;
+import android.animation.ObjectAnimator;
+import android.animation.ValueAnimator;
+import android.animation.ValueAnimator.AnimatorUpdateListener;
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.util.AttributeSet;
+import android.view.View;
+
+import com.android.launcher3.Workspace.State;
+
+/**
+ * A simple view used to show the region blocked by QSB during drag and drop.
+ */
+public class QsbBlockerView extends View implements Workspace.OnStateChangeListener {
+
+    private static final int VISIBLE_ALPHA = 100;
+
+    private final Paint mBgPaint;
+
+    public QsbBlockerView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+
+        mBgPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
+        mBgPaint.setColor(Color.WHITE);
+        mBgPaint.setAlpha(0);
+    }
+
+    @Override
+    protected void onAttachedToWindow() {
+        super.onAttachedToWindow();
+
+        Workspace w = Launcher.getLauncher(getContext()).getWorkspace();
+        w.setOnStateChangeListener(this);
+        prepareStateChange(w.getState(), null);
+    }
+
+    @Override
+    public void prepareStateChange(State toState, AnimatorSet targetAnim) {
+        int finalAlpha = getAlphaForState(toState);
+        if (targetAnim == null) {
+            mBgPaint.setAlpha(finalAlpha);
+            invalidate();
+        } else {
+            ObjectAnimator anim = ObjectAnimator.ofArgb(mBgPaint, "alpha", finalAlpha);
+            anim.addUpdateListener(new AnimatorUpdateListener() {
+                @Override
+                public void onAnimationUpdate(ValueAnimator valueAnimator) {
+                    invalidate();
+                }
+            });
+            targetAnim.play(anim);
+        }
+    }
+
+    private static int getAlphaForState(State state) {
+        switch (state) {
+            case SPRING_LOADED:
+            case OVERVIEW:
+            case OVERVIEW_HIDDEN:
+                return VISIBLE_ALPHA;
+        }
+        return 0;
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        canvas.drawPaint(mBgPaint);
+    }
+}
diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index 8d46719..7812a5b 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -578,11 +578,10 @@
         if (qsb == null) {
             // In transposed layout, we add the QSB in the Grid. As workspace does not touch the
             // edges, we do not need a full width QSB.
-            if (mLauncher.getDeviceProfile().isVerticalBarLayout()) {
-                qsb = mLauncher.getLayoutInflater().inflate(R.layout.qsb_container, firstPage, false);
-            } else {
-                qsb = new Space(getContext());
-            }
+            qsb = mLauncher.getLayoutInflater().inflate(
+                    mLauncher.getDeviceProfile().isVerticalBarLayout()
+                            ? R.layout.qsb_container : R.layout.qsb_blocker_view,
+                    firstPage, false);
         }
 
         CellLayout.LayoutParams lp = new CellLayout.LayoutParams(0, 0, firstPage.getCountX(), 1);
@@ -2147,7 +2146,7 @@
         return workspaceAnim;
     }
 
-    State getState() {
+    public State getState() {
         return mState;
     }