Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * Copyright (C) 2012 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.autoscrollview.widget.indicator; import static android.view.ViewGroup.LayoutParams.FILL_PARENT; import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT; 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.Gravity; import android.view.View; import android.widget.HorizontalScrollView; import android.widget.ImageView; import com.hldj.hmyg.R; /** * This widget implements the dynamic action bar tab behavior that can change * across different configurations or circumstances. */ public class IconPageIndicator extends HorizontalScrollView implements PageIndicator { private final IcsLinearLayout mIconsLayout; private ViewPager mViewPager; private OnPageChangeListener mListener; private Runnable mIconSelector; private int mSelectedIndex; public IconPageIndicator(Context context) { this(context, null); } public IconPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); mIconsLayout = new IcsLinearLayout(context, R.attr.vpiIconPageIndicatorStyle); addView(mIconsLayout, new LayoutParams(WRAP_CONTENT, FILL_PARENT, Gravity.CENTER)); } private void animateToIcon(final int position) { final View iconView = mIconsLayout.getChildAt(position); if (mIconSelector != null) { removeCallbacks(mIconSelector); } mIconSelector = new Runnable() { public void run() { final int scrollPos = iconView.getLeft() - (getWidth() - iconView.getWidth()) / 2; smoothScrollTo(scrollPos, 0); mIconSelector = null; } }; post(mIconSelector); } @Override public void onAttachedToWindow() { super.onAttachedToWindow(); if (mIconSelector != null) { // Re-post the selector we saved post(mIconSelector); } } @Override public void onDetachedFromWindow() { super.onDetachedFromWindow(); if (mIconSelector != null) { removeCallbacks(mIconSelector); } } @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); } 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() { mIconsLayout.removeAllViews(); IconPagerAdapter iconAdapter = (IconPagerAdapter) mViewPager.getAdapter(); int count = iconAdapter.getCount(); for (int i = 0; i < count; i++) { ImageView view = new ImageView(getContext(), null, R.attr.vpiIconPageIndicatorStyle); view.setImageResource(iconAdapter.getIconResId(i)); mIconsLayout.addView(view); } if (mSelectedIndex > count) { mSelectedIndex = count - 1; } setCurrentItem(mSelectedIndex); 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."); } mSelectedIndex = item; mViewPager.setCurrentItem(item); int tabCount = mIconsLayout.getChildCount(); for (int i = 0; i < tabCount; i++) { View child = mIconsLayout.getChildAt(i); boolean isSelected = (i == item); child.setSelected(isSelected); if (isSelected) { animateToIcon(item); } } } @Override public void setOnPageChangeListener(OnPageChangeListener listener) { mListener = listener; } }