ViewPagerTabs.java revision d6ffb82e7684ea4a5caa9313d9bfc87980cadc91 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package com.android.contacts.common.list;
17
18import android.content.Context;
19import android.content.res.ColorStateList;
20import android.content.res.TypedArray;
21import android.graphics.Outline;
22import android.support.v4.view.PagerAdapter;
23import android.support.v4.view.ViewPager;
24import android.util.AttributeSet;
25import android.util.TypedValue;
26import android.view.Gravity;
27import android.view.LayoutInflater;
28import android.view.View;
29import android.view.ViewOutlineProvider;
30import android.widget.FrameLayout;
31import android.widget.HorizontalScrollView;
32import android.widget.LinearLayout;
33import android.widget.TextView;
34import android.widget.Toast;
35
36import com.android.contacts.common.R;
37
38/**
39 * Lightweight implementation of ViewPager tabs. This looks similar to traditional actionBar tabs,
40 * but allows for the view containing the tabs to be placed anywhere on screen. Text-related
41 * attributes can also be assigned in XML - these will get propogated to the child TextViews
42 * automatically.
43 */
44public class ViewPagerTabs extends HorizontalScrollView implements ViewPager.OnPageChangeListener {
45
46    ViewPager mPager;
47    private ViewPagerTabStrip mTabStrip;
48
49    /**
50     * Linearlayout that will contain the TextViews serving as tabs. This is the only child
51     * of the parent HorizontalScrollView.
52     */
53    final int mTextStyle;
54    final ColorStateList mTextColor;
55    final int mTextSize;
56    final boolean mTextAllCaps;
57    int mPrevSelected = -1;
58    int mSidePadding;
59
60    private int[] mTabIcons;
61    // For displaying the unread count next to the tab icon.
62    private int[] mUnreadCounts;
63
64    private static final ViewOutlineProvider VIEW_BOUNDS_OUTLINE_PROVIDER =
65            new ViewOutlineProvider() {
66        @Override
67        public void getOutline(View view, Outline outline) {
68            outline.setRect(0, 0, view.getWidth(), view.getHeight());
69        }
70    };
71
72    private static final int TAB_SIDE_PADDING_IN_DPS = 10;
73
74    // TODO: This should use <declare-styleable> in the future
75    private static final int[] ATTRS = new int[] {
76        android.R.attr.textSize,
77        android.R.attr.textStyle,
78        android.R.attr.textColor,
79        android.R.attr.textAllCaps
80    };
81
82    /**
83     * Simulates actionbar tab behavior by showing a toast with the tab title when long clicked.
84     */
85    private class OnTabLongClickListener implements OnLongClickListener {
86        final int mPosition;
87
88        public OnTabLongClickListener(int position) {
89            mPosition = position;
90        }
91
92        @Override
93        public boolean onLongClick(View v) {
94            final int[] screenPos = new int[2];
95            getLocationOnScreen(screenPos);
96
97            final Context context = getContext();
98            final int width = getWidth();
99            final int height = getHeight();
100            final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;
101
102            Toast toast = Toast.makeText(context, mPager.getAdapter().getPageTitle(mPosition),
103                    Toast.LENGTH_SHORT);
104
105            // Show the toast under the tab
106            toast.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL,
107                    (screenPos[0] + width / 2) - screenWidth / 2, screenPos[1] + height);
108
109            toast.show();
110            return true;
111        }
112    }
113
114    public ViewPagerTabs(Context context) {
115        this(context, null);
116    }
117
118    public ViewPagerTabs(Context context, AttributeSet attrs) {
119        this(context, attrs, 0);
120    }
121
122    public ViewPagerTabs(Context context, AttributeSet attrs, int defStyle) {
123        super(context, attrs, defStyle);
124        setFillViewport(true);
125
126        mSidePadding = (int) (getResources().getDisplayMetrics().density * TAB_SIDE_PADDING_IN_DPS);
127
128        final TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);
129        mTextSize = a.getDimensionPixelSize(0, 0);
130        mTextStyle = a.getInt(1, 0);
131        mTextColor = a.getColorStateList(2);
132        mTextAllCaps = a.getBoolean(3, false);
133
134        mTabStrip = new ViewPagerTabStrip(context);
135        addView(mTabStrip,
136                new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
137        a.recycle();
138
139        // enable shadow casting from view bounds
140        setOutlineProvider(VIEW_BOUNDS_OUTLINE_PROVIDER);
141    }
142
143    public void setViewPager(ViewPager viewPager) {
144        mPager = viewPager;
145        addTabs(mPager.getAdapter());
146    }
147
148    /**
149     * Set the tab icons and initialize an array for unread counts the same length as the icon
150     * array.
151     *
152     * @param tabIcons An array representing the tab icons in order.
153     */
154    public void configureTabIcons(int[] tabIcons) {
155        mTabIcons = tabIcons;
156        mUnreadCounts = new int[tabIcons.length];
157    }
158
159    public void setUnreadCount(int count, int position) {
160        if (mUnreadCounts == null || position >= mUnreadCounts.length) {
161            return;
162        }
163        mUnreadCounts[position] = count;
164    }
165
166    private void addTabs(PagerAdapter adapter) {
167        mTabStrip.removeAllViews();
168
169        final int count = adapter.getCount();
170        for (int i = 0; i < count; i++) {
171            addTab(adapter.getPageTitle(i), i);
172        }
173    }
174
175    private void addTab(CharSequence tabTitle, final int position) {
176        View tabView;
177        if (mTabIcons != null && position < mTabIcons.length) {
178            View layout = LayoutInflater.from(getContext()).inflate(
179                    R.layout.unread_count_tab, null);
180            View iconView = layout.findViewById(R.id.icon);
181            iconView.setBackgroundResource(mTabIcons[position]);
182            iconView.setContentDescription(tabTitle);
183            TextView textView = (TextView) layout.findViewById(R.id.count);
184            if (mUnreadCounts != null && mUnreadCounts[position] > 0) {
185                textView.setText(Integer.toString(mUnreadCounts[position]));
186                textView.setVisibility(View.VISIBLE);
187            } else {
188                textView.setVisibility(View.INVISIBLE);
189            }
190            tabView = layout;
191        } else {
192            final TextView textView = new TextView(getContext());
193            textView.setText(tabTitle);
194            textView.setBackgroundResource(R.drawable.view_pager_tab_background);
195
196            // Assign various text appearance related attributes to child views.
197            if (mTextStyle > 0) {
198                textView.setTypeface(textView.getTypeface(), mTextStyle);
199            }
200            if (mTextSize > 0) {
201                textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
202            }
203            if (mTextColor != null) {
204                textView.setTextColor(mTextColor);
205            }
206            textView.setAllCaps(mTextAllCaps);
207            textView.setGravity(Gravity.CENTER);
208
209            tabView = textView;
210        }
211
212        tabView.setOnClickListener(new OnClickListener() {
213            @Override
214            public void onClick(View v) {
215                mPager.setCurrentItem(getRtlPosition(position));
216            }
217        });
218
219        tabView.setOnLongClickListener(new OnTabLongClickListener(position));
220
221        tabView.setPadding(mSidePadding, 0, mSidePadding, 0);
222
223        mTabStrip.addView(tabView, position, new LinearLayout.LayoutParams(
224                LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT, 1));
225
226        // Default to the first child being selected
227        if (position == 0) {
228            mPrevSelected = 0;
229            tabView.setSelected(true);
230        }
231    }
232
233    /**
234     * Refresh a tab at a certain index by removing it and reconstructing it.
235     *
236     * @param index The index of the tab view we wish to update.
237     */
238    public void updateTab(int index) {
239        View view = mTabStrip.getChildAt(index);
240        mTabStrip.removeView(view);
241        addTab(mPager.getAdapter().getPageTitle(index), index);
242    }
243
244    @Override
245    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
246        position = getRtlPosition(position);
247        int tabStripChildCount = mTabStrip.getChildCount();
248        if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
249            return;
250        }
251
252        mTabStrip.onPageScrolled(position, positionOffset, positionOffsetPixels);
253    }
254
255    @Override
256    public void onPageSelected(int position) {
257        position = getRtlPosition(position);
258        int tabStripChildCount = mTabStrip.getChildCount();
259        if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
260            return;
261        }
262
263        if (mPrevSelected >= 0 && mPrevSelected < tabStripChildCount) {
264            mTabStrip.getChildAt(mPrevSelected).setSelected(false);
265        }
266        final View selectedChild = mTabStrip.getChildAt(position);
267        selectedChild.setSelected(true);
268
269        // Update scroll position
270        final int scrollPos = selectedChild.getLeft() - (getWidth() - selectedChild.getWidth()) / 2;
271        smoothScrollTo(scrollPos, 0);
272        mPrevSelected = position;
273    }
274
275    @Override
276    public void onPageScrollStateChanged(int state) {
277    }
278
279    private int getRtlPosition(int position) {
280        if (getLayoutDirection() == View.LAYOUT_DIRECTION_RTL) {
281            return mTabStrip.getChildCount() - 1 - position;
282        }
283        return position;
284    }
285}
286
287