Updating the UI for focused state of an icon/folder.

issue: 16352129

Change-Id: If2e154dba06a0648f933f9aea38898642db9fd85

src/com/android/launcher3/FocusIndicatorView.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2011 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.content.Context;
+import android.graphics.Canvas;
+import android.util.AttributeSet;
+import android.util.Pair;
+import android.view.View;
+import android.view.ViewParent;
+
+public class FocusIndicatorView extends View implements View.OnFocusChangeListener {
+
+    // It can be any number >0. The view is resized using scaleX and scaleY.
+    static final int DEFAULT_LAYOUT_SIZE = 100;
+    private static final float MIN_VISIBLE_ALPHA = 0.2f;
+
+    private static final int[] sTempPos = new int[2];
+    private static final int[] sTempShift = new int[2];
+
+    private final int[] mIndicatorPos = new int[2];
+    private final int[] mTargetViewPos = new int[2];
+
+    private View mLastFocusedView;
+    private boolean mInitiated;
+
+    private Pair<View, Boolean> mPendingCall;
+
+    public FocusIndicatorView(Context context) {
+        this(context, null);
+    }
+
+    public FocusIndicatorView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        setAlpha(0);
+        setBackgroundColor(getResources().getColor(R.color.focused_background));
+    }
+
+    @Override
+    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
+        super.onSizeChanged(w, h, oldw, oldh);
+
+        // Redraw if it is already showing. This avoids a bug where the height changes by a small
+        // amount on connecting/disconnecting a bluetooth keyboard.
+        if (mLastFocusedView != null) {
+            mPendingCall = Pair.create(mLastFocusedView, Boolean.TRUE);
+            invalidate();
+        }
+    }
+
+    @Override
+    public void onFocusChange(View v, boolean hasFocus) {
+        mPendingCall = null;
+        if (!mInitiated && (getWidth() == 0)) {
+            // View not yet laid out. Wait until the view is ready to be drawn, so that be can
+            // get the location on screen.
+            mPendingCall = Pair.create(v, hasFocus);
+            invalidate();
+            return;
+        }
+
+        if (!mInitiated) {
+            getLocationRelativeToParentPagedView(this, mIndicatorPos);
+            mInitiated = true;
+        }
+
+        if (hasFocus) {
+            int indicatorWidth = getWidth();
+            int indicatorHeight = getHeight();
+
+            float scaleX = v.getScaleX() * v.getWidth() / indicatorWidth;
+            float scaleY = v.getScaleY() * v.getHeight() / indicatorHeight;
+
+            getLocationRelativeToParentPagedView(v, mTargetViewPos);
+            float x = mTargetViewPos[0] - mIndicatorPos[0] - (1 - scaleX) * indicatorWidth / 2;
+            float y = mTargetViewPos[1] - mIndicatorPos[1] - (1 - scaleY) * indicatorHeight / 2;
+
+            if (getAlpha() > MIN_VISIBLE_ALPHA) {
+                animate()
+                .translationX(x)
+                .translationY(y)
+                .scaleX(scaleX)
+                .scaleY(scaleY)
+                .alpha(1);
+            } else {
+                setTranslationX(x);
+                setTranslationY(y);
+                setScaleX(scaleX);
+                setScaleY(scaleY);
+                animate().alpha(1);
+            }
+            mLastFocusedView = v;
+        } else {
+            if (mLastFocusedView == v) {
+                mLastFocusedView = null;
+                animate().alpha(0);
+            }
+        }
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        if (mPendingCall != null) {
+            onFocusChange(mPendingCall.first, mPendingCall.second);
+        }
+    }
+
+    /**
+     * Gets the location of a view relative in the window, off-setting any shift due to
+     * page view scroll
+     */
+    private static void getLocationRelativeToParentPagedView(View v, int[] pos) {
+        getPagedViewScrollShift(v, sTempShift);
+        v.getLocationInWindow(sTempPos);
+        pos[0] = sTempPos[0] + sTempShift[0];
+        pos[1] = sTempPos[1] + sTempShift[1];
+    }
+
+    private static void getPagedViewScrollShift(View child, int[] shift) {
+        ViewParent parent = child.getParent();
+        if (parent instanceof PagedView) {
+            View parentView = (View) parent;
+            child.getLocationInWindow(sTempPos);
+            shift[0] = parentView.getPaddingLeft() - sTempPos[0];
+            shift[1] = -(int) child.getTranslationY();
+        } else if (parent instanceof View) {
+            getPagedViewScrollShift((View) parent, shift);
+        } else {
+            shift[0] = shift[1] = 0;
+        }
+    }
+}