ControlBar.java revision 6e28bd2903a19cd4560d94413161bd3fa36542e6 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14package android.support.v17.leanback.widget;
15
16import android.content.Context;
17import android.graphics.Rect;
18import android.util.AttributeSet;
19import android.view.View;
20import android.view.ViewGroup;
21import android.widget.LinearLayout;
22
23import java.util.ArrayList;
24
25class ControlBar extends LinearLayout {
26
27    public interface OnChildFocusedListener {
28        public void onChildFocusedListener(View child, View focused);
29    }
30
31    private int mChildMarginFromCenter;
32    private OnChildFocusedListener mOnChildFocusedListener;
33    int mLastFocusIndex = -1;
34
35    public ControlBar(Context context, AttributeSet attrs) {
36        super(context, attrs);
37    }
38
39    public ControlBar(Context context, AttributeSet attrs, int defStyle) {
40        super(context, attrs, defStyle);
41    }
42
43    @Override
44    protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) {
45        if (getChildCount() > 0) {
46            int index = mLastFocusIndex >= 0 && mLastFocusIndex < getChildCount()
47                    ? mLastFocusIndex : getChildCount() / 2;
48            if (getChildAt(index).requestFocus(direction, previouslyFocusedRect)) {
49                return true;
50            }
51        }
52        return super.onRequestFocusInDescendants(direction, previouslyFocusedRect);
53    }
54
55    @Override
56    public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
57        if ((direction == ViewGroup.FOCUS_UP || direction == ViewGroup.FOCUS_DOWN)) {
58            if (mLastFocusIndex >= 0 && mLastFocusIndex < getChildCount()) {
59                views.add(getChildAt(mLastFocusIndex));
60            } else if (getChildCount() > 0) {
61                views.add(getChildAt(getChildCount() / 2));
62            }
63        } else {
64            super.addFocusables(views, direction, focusableMode);
65        }
66    }
67
68    public void setOnChildFocusedListener(OnChildFocusedListener listener) {
69        mOnChildFocusedListener = listener;
70    }
71
72    public void setChildMarginFromCenter(int marginFromCenter) {
73        mChildMarginFromCenter = marginFromCenter;
74    }
75
76    @Override
77    public void requestChildFocus (View child, View focused) {
78        super.requestChildFocus(child, focused);
79        mLastFocusIndex = indexOfChild(child);
80        if (mOnChildFocusedListener != null) {
81            mOnChildFocusedListener.onChildFocusedListener(child, focused);
82        }
83    }
84
85    @Override
86    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
87        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
88        if (mChildMarginFromCenter <= 0) {
89            return;
90        }
91
92        int totalExtraMargin = 0;
93        for (int i = 0; i < getChildCount() - 1; i++) {
94            View first = getChildAt(i);
95            View second = getChildAt(i+1);
96            int measuredWidth = first.getMeasuredWidth() + second.getMeasuredWidth();
97            int marginStart = mChildMarginFromCenter - measuredWidth / 2;
98            LayoutParams lp = (LayoutParams) second.getLayoutParams();
99            int extraMargin = marginStart - lp.getMarginStart();
100            lp.setMarginStart(marginStart);
101            second.setLayoutParams(lp);
102            totalExtraMargin += extraMargin;
103        }
104        setMeasuredDimension(getMeasuredWidth() + totalExtraMargin, getMeasuredHeight());
105    }
106}
107