Add BandSelectManager.

BUG:20669231

Change-Id: Iea8c3866a9de020a7bebd93a967aa42d45f8e2bd

packages/DocumentsUI/res/drawable/band_select_overlay.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2015 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
+  -->
+
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+        android:shape="rectangle">
+    <solid android:color="@color/band_select_background" />
+    <stroke android:width="1dp" android:color="@color/band_select_border" />
+</shape>

packages/DocumentsUI/res/values/colors.xml

@@ -27,4 +27,6 @@
     <color name="item_doc_grid_protect_background">#88000000</color>
     <color name="status_bar_background">@color/material_blue_700</color>
     <color name="action_mode_status_bar_background">@color/material_grey_800</color>
+    <color name="band_select_background">#88ffffff</color>
+    <color name="band_select_border">#44000000</color>
 </resources>

packages/DocumentsUI/src/com/android/documentsui/BandSelectManager.java

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2015 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.internal.util.Preconditions.checkState;
+
+import android.graphics.Point;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.view.View;
+
+/**
+ * Provides mouse driven band-select support when used in conjuction with {@link RecyclerView} and
+ * {@link MultiSelectManager}. This class is responsible for rendering the band select overlay and
+ * selecting overlaid items via MultiSelectManager.
+ */
+public class BandSelectManager extends RecyclerView.SimpleOnItemTouchListener {
+
+    // For debugging purposes.
+    private static final String TAG = "BandSelectManager";
+    private static final boolean DEBUG = false;
+
+    private final RecyclerView mRecyclerView;
+    private final MultiSelectManager mSelectManager;
+    private final Drawable mRegionSelectorDrawable;
+
+    private boolean mIsBandSelectActive = false;
+    private Point mOrigin;
+    private Rect mRegionBounds;
+
+    /**
+     * @param recyclerView
+     * @param multiSelectManager
+     */
+    public BandSelectManager(RecyclerView recyclerView, MultiSelectManager multiSelectManager) {
+        mRecyclerView = recyclerView;
+        mSelectManager = multiSelectManager;
+        mRegionSelectorDrawable =
+            mRecyclerView.getContext().getTheme().getDrawable(R.drawable.band_select_overlay);
+
+        mRecyclerView.addOnItemTouchListener(this);
+    }
+
+    @Override
+    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
+        // Only intercept the event if it was triggered by a mouse. If band select is inactive,
+        // do not intercept ACTION_UP events as they will not be processed.
+        return isMouseEvent(e) &&
+                (mIsBandSelectActive || e.getActionMasked() != MotionEvent.ACTION_UP);
+    }
+
+    @Override
+    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
+        checkState(isMouseEvent(e));
+        processMotionEvent(e);
+    }
+
+    /**
+     * Processes a MotionEvent by starting, ending, or resizing the band select overlay.
+     * @param e
+     */
+    private void processMotionEvent(MotionEvent e) {
+        if (mIsBandSelectActive && e.getActionMasked() == MotionEvent.ACTION_UP) {
+            endBandSelect();
+            return;
+        }
+
+        Point point = new Point((int) e.getX(), (int) e.getY());
+        if (!mIsBandSelectActive) {
+            startBandSelect(point);
+        }
+
+        resizeBandSelectRectangle(point);
+        selectChildrenCoveredBySelection();
+    }
+
+    /**
+     * Starts band select by adding the drawable to the RecyclerView's overlay.
+     * @param origin The starting point of the selection.
+     */
+    private void startBandSelect(Point origin) {
+        if (DEBUG) Log.d(TAG, "Starting band select from (" + origin.x + "," + origin.y + ").");
+        mIsBandSelectActive = true;
+        mOrigin = origin;
+        mRecyclerView.getOverlay().add(mRegionSelectorDrawable);
+    }
+
+    /**
+     * Resizes the band select rectangle by using the origin and the current pointer positoin as
+     * two opposite corners of the selection.
+     * @param pointerPosition
+     */
+    private void resizeBandSelectRectangle(Point pointerPosition) {
+        mRegionBounds = new Rect(Math.min(mOrigin.x, pointerPosition.x),
+                Math.min(mOrigin.y, pointerPosition.y),
+                Math.max(mOrigin.x, pointerPosition.x),
+                Math.max(mOrigin.y, pointerPosition.y));
+        mRegionSelectorDrawable.setBounds(mRegionBounds);
+    }
+
+    /**
+     * Selects the children covered by the band select overlay by delegating to MultiSelectManager.
+     * TODO: Provide a finished implementation. This is down and dirty, proof of concept code.
+     * Final optimized implementation, with support for managing offscreen selection to come.
+     */
+    private void selectChildrenCoveredBySelection() {
+        for (int i = 0; i < mRecyclerView.getChildCount(); i++) {
+            View child = mRecyclerView.getChildAt(i);
+            ViewHolder holder = mRecyclerView.getChildViewHolder(child);
+            Rect childRect = new Rect();
+            child.getHitRect(childRect);
+
+            boolean doRectsOverlap = Rect.intersects(childRect, mRegionBounds);
+            mSelectManager.setItemSelected(holder.getAdapterPosition(), doRectsOverlap);
+        }
+    }
+
+    /**
+     * Ends band select by removing the overlay.
+     */
+    private void endBandSelect() {
+        if (DEBUG) Log.d(TAG, "Ending band select.");
+        mIsBandSelectActive = false;
+        mRecyclerView.getOverlay().remove(mRegionSelectorDrawable);
+    }
+
+    /**
+     * Determines whether the provided event was triggered by a mouse (as opposed to a finger or
+     * stylus).
+     * @param e
+     * @return
+     */
+    private static boolean isMouseEvent(MotionEvent e) {
+        return e.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE;
+    }
+}

packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java

@@ -397,6 +397,7 @@ public class DirectoryFragment extends Fragment {
         // Kick off loader at least once
         getLoaderManager().restartLoader(LOADER_ID, null, mCallbacks);
 
+        mFragmentTuner.afterActivityCreated(this);
         updateDisplayState();
     }
 
@@ -1662,6 +1663,7 @@ public class DirectoryFragment extends Fragment {
      */
     private interface FragmentTuner {
         void updateActionMenu(Menu menu, int dirType, boolean canDelete);
+        void afterActivityCreated(DirectoryFragment fragment);
     }
 
     /**
@@ -1719,6 +1721,9 @@ public class DirectoryFragment extends Fragment {
             // Only shown in standalone mode.
             copyToClipboard.setVisible(false);
         }
+
+        @Override
+        public void afterActivityCreated(DirectoryFragment fragment) {}
     }
 
     /**
@@ -1735,5 +1740,10 @@ public class DirectoryFragment extends Fragment {
             menu.findItem(R.id.menu_copy_to).setVisible(false);
             menu.findItem(R.id.menu_move_to).setVisible(false);
         }
+
+        @Override
+        public void afterActivityCreated(DirectoryFragment fragment) {
+            new BandSelectManager(fragment.mRecView, fragment.mSelectionManager);
+        }
     }
 }