net.peterkuterna.android.apps.devoxxfrsched.ui.widget.ScrollableTabs.java Source code

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Here is the source code for net.peterkuterna.android.apps.devoxxfrsched.ui.widget.ScrollableTabs.java

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/*
 * Copyright 2011 Peter Kuterna
 *
 * 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 net.peterkuterna.android.apps.devoxxfrsched.ui.widget;

import android.content.Context;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ScrollableTabs extends HorizontalScrollView implements OnPageChangeListener {

    private LinearLayout mHost;
    private ScrollableTabsAdapter mAdapter;
    private int mCurrentTab = -1;

    public ScrollableTabs(Context context) {
        this(context, null);
    }

    public ScrollableTabs(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ScrollableTabs(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        init();
    }

    private void init() {
        mHost = new LinearLayout(getContext());
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT);
        addView(mHost, layoutParams);

        setHorizontalScrollBarEnabled(false);
        setFillViewport(true);
    }

    public void setAdapter(ScrollableTabsAdapter adapter) {
        if (mAdapter != null) {
            // TODO: data set observer
        }

        mAdapter = adapter;

        // clean up our childs
        mCurrentTab = -1;
        mHost.removeAllViews();

        if (mAdapter != null) {
            final int count = mAdapter.getCount();

            // add the child text views
            for (int i = 0; i < count; i++) {
                mHost.addView(mAdapter.getTab(i, mHost),
                        new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT));
            }

            if (count > 0) {
                focusTab(0);
                // mCurrentTab = 0;
            }

            requestLayout();
            invalidate();
        }
    }

    public void focusTab(int index) {
        final int tabCount = mHost.getChildCount();

        if (index < 0 || index > tabCount - 1) {
            return;
        }

        if (mCurrentTab != index) {
            final TextView tvOld = (TextView) mHost.getChildAt(mCurrentTab);
            if (tvOld != null) {
                tvOld.setSelected(false);
            }

            mCurrentTab = index;

            final TextView tvNew = (TextView) mHost.getChildAt(index);
            if (tvNew != null) {
                int right = tvNew.getRight();
                int left = tvNew.getLeft() + right;
                int width = getWidth();
                int i = (left - width) / 2;
                tvNew.setSelected(true);
                smoothScrollTo(i, 0);
            }
        }
    }

    @Override
    public void onPageScrollStateChanged(int state) {
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    }

    @Override
    public void onPageSelected(int position) {
        focusTab(position);
    }

}