Subversion Repositories SmartDukaan

/*

 * Copyright (C) 2011 The Android Open Source Project

 * Copyright (C) 2011 Jake Wharton

 *

 * 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.viewpagerindicator;

import android.content.Context;

import android.support.v4.view.PagerAdapter;

import android.support.v4.view.ViewPager;

import android.support.v4.view.ViewPager.OnPageChangeListener;

import android.util.AttributeSet;

import android.view.View;

import android.view.ViewGroup;

import android.widget.HorizontalScrollView;

import android.widget.LinearLayout;

import android.widget.TextView;

import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;

import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;

/**

 * This widget implements the dynamic action bar tab behavior that can change

 * across different configurations or circumstances.

 */

public class TabPageIndicator extends HorizontalScrollView implements PageIndicator {

    /** Title text used when no title is provided by the adapter. */

    private static final CharSequence EMPTY_TITLE = "";

    /**

     * Interface for a callback when the selected tab has been reselected.

     */

    public interface OnTabReselectedListener {

        /**

         * Callback when the selected tab has been reselected.

         *

         * @param position Position of the current center item.

         */

        void onTabReselected(int position);

    }

    private Runnable mTabSelector;

    private final OnClickListener mTabClickListener = new OnClickListener() {

        public void onClick(View view) {

            TabView tabView = (TabView)view;

            final int oldSelected = mViewPager.getCurrentItem();

            final int newSelected = tabView.getIndex();

            mViewPager.setCurrentItem(newSelected);

            if (oldSelected == newSelected && mTabReselectedListener != null) {

                mTabReselectedListener.onTabReselected(newSelected);

            }

        }

    };

    private final IcsLinearLayout mTabLayout;

    private ViewPager mViewPager;

    private ViewPager.OnPageChangeListener mListener;

    private int mMaxTabWidth;

    private int mSelectedTabIndex;

    private OnTabReselectedListener mTabReselectedListener;

    public TabPageIndicator(Context context) {

        this(context, null);

    }

    public TabPageIndicator(Context context, AttributeSet attrs) {

        super(context, attrs);

        setHorizontalScrollBarEnabled(false);

        mTabLayout = new IcsLinearLayout(context, R.attr.vpiTabPageIndicatorStyle);

        addView(mTabLayout, new ViewGroup.LayoutParams(WRAP_CONTENT, MATCH_PARENT));

    }

    public void setOnTabReselectedListener(OnTabReselectedListener listener) {

        mTabReselectedListener = listener;

    }

    @Override

    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        final boolean lockedExpanded = widthMode == MeasureSpec.EXACTLY;

        setFillViewport(lockedExpanded);

        final int childCount = mTabLayout.getChildCount();

        if (childCount > 1 && (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST)) {

            if (childCount > 2) {

                mMaxTabWidth = (int)(MeasureSpec.getSize(widthMeasureSpec) * 0.4f);

            } else {

                mMaxTabWidth = MeasureSpec.getSize(widthMeasureSpec) / 2;

            }

        } else {

            mMaxTabWidth = -1;

        }

        final int oldWidth = getMeasuredWidth();

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        final int newWidth = getMeasuredWidth();

        if (lockedExpanded && oldWidth != newWidth) {

            // Recenter the tab display if we're at a new (scrollable) size.

            setCurrentItem(mSelectedTabIndex);

        }

    }

    private void animateToTab(final int position) {

        final View tabView = mTabLayout.getChildAt(position);

        if (mTabSelector != null) {

            removeCallbacks(mTabSelector);

        }

        mTabSelector = new Runnable() {

            public void run() {

                final int scrollPos = tabView.getLeft() - (getWidth() - tabView.getWidth()) / 2;

                smoothScrollTo(scrollPos, 0);

                mTabSelector = null;

            }

        };

        post(mTabSelector);

    }

    @Override

    public void onAttachedToWindow() {

        super.onAttachedToWindow();

        if (mTabSelector != null) {

            // Re-post the selector we saved

            post(mTabSelector);

        }

    }

    @Override

    public void onDetachedFromWindow() {

        super.onDetachedFromWindow();

        if (mTabSelector != null) {

            removeCallbacks(mTabSelector);

        }

    }

    private void addTab(int index, CharSequence text, int iconResId) {

        final TabView tabView = new TabView(getContext());

        tabView.mIndex = index;

        tabView.setFocusable(true);

        tabView.setOnClickListener(mTabClickListener);

        tabView.setText(text);

        if (iconResId != 0) {

            tabView.setCompoundDrawablesWithIntrinsicBounds(iconResId, 0, 0, 0);

        }

        mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0, MATCH_PARENT, 1));

    }

    @Override

    public void onPageScrollStateChanged(int arg0) {

        if (mListener != null) {

            mListener.onPageScrollStateChanged(arg0);

        }

    }

    @Override

    public void onPageScrolled(int arg0, float arg1, int arg2) {

        if (mListener != null) {

            mListener.onPageScrolled(arg0, arg1, arg2);

        }

    }

    @Override

    public void onPageSelected(int arg0) {

        setCurrentItem(arg0);

        if (mListener != null) {

            mListener.onPageSelected(arg0);

        }

    }

    @Override

    public void setViewPager(ViewPager view) {

        if (mViewPager == view) {

            return;

        }

        if (mViewPager != null) {

            mViewPager.setOnPageChangeListener(null);

        }

        final PagerAdapter adapter = view.getAdapter();

        if (adapter == null) {

            throw new IllegalStateException("ViewPager does not have adapter instance.");

        }

        mViewPager = view;

        view.setOnPageChangeListener(this);

        notifyDataSetChanged();

    }

    public void notifyDataSetChanged() {

        mTabLayout.removeAllViews();

        PagerAdapter adapter = mViewPager.getAdapter();

        IconPagerAdapter iconAdapter = null;

        if (adapter instanceof IconPagerAdapter) {

            iconAdapter = (IconPagerAdapter)adapter;

        }

        final int count = adapter.getCount();

        for (int i = 0; i < count; i++) {

            CharSequence title = adapter.getPageTitle(i);

            if (title == null) {

                title = EMPTY_TITLE;

            }

            int iconResId = 0;

            if (iconAdapter != null) {

                iconResId = iconAdapter.getIconResId(i);

            }

            addTab(i, title, iconResId);

        }

        if (mSelectedTabIndex > count) {

            mSelectedTabIndex = count - 1;

        }

        setCurrentItem(mSelectedTabIndex);

        requestLayout();

    }

    @Override

    public void setViewPager(ViewPager view, int initialPosition) {

        setViewPager(view);

        setCurrentItem(initialPosition);

    }

    @Override

    public void setCurrentItem(int item) {

        if (mViewPager == null) {

            throw new IllegalStateException("ViewPager has not been bound.");

        }

        mSelectedTabIndex = item;

        mViewPager.setCurrentItem(item);

        final int tabCount = mTabLayout.getChildCount();

        for (int i = 0; i < tabCount; i++) {

            final View child = mTabLayout.getChildAt(i);

            final boolean isSelected = (i == item);

            child.setSelected(isSelected);

            if (isSelected) {

                animateToTab(item);

            }

        }

    }

    @Override

    public void setOnPageChangeListener(OnPageChangeListener listener) {

        mListener = listener;

    }

    private class TabView extends TextView {

        private int mIndex;

        public TabView(Context context) {

            super(context, null, R.attr.vpiTabPageIndicatorStyle);

        }

        @Override

        public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

            super.onMeasure(widthMeasureSpec, heightMeasureSpec);

            // Re-measure if we went beyond our maximum size.

            if (mMaxTabWidth > 0 && getMeasuredWidth() > mMaxTabWidth) {

                super.onMeasure(MeasureSpec.makeMeasureSpec(mMaxTabWidth, MeasureSpec.EXACTLY),

                        heightMeasureSpec);

            }

        }

        public int getIndex() {

            return mIndex;

        }

    }

}