package com.itheima18.viewpager;

import java.util.ArrayList;
import java.util.Timer;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {

	private ViewPager viewPager;
	private TextView title;
	private int[] imageIds;
	private ArrayList images;
	private String[] titles;
	private ArrayList dots;
	private MyPagerAdapter adapter;

	private int oldPosition = 0;// 上一次圓點的位置
	private ScheduledExecutorService scheduledExecutor;

	private int currentIndex = 0; // 當前頁面的位置

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		initData();
		initView();
	}

	// 準備初始化資料
	private void initData() {

		// 圖片
		imageIds = new int[] { R.drawable.a, R.drawable.b, R.drawable.c,
				R.drawable.d, R.drawable.e };
		// 用來顯示的圖片
		images = new ArrayList();
		for (int i = 0; i < imageIds.length; i++) {

			ImageView imageView = new ImageView(getApplicationContext());
			imageView.setImageResource(imageIds[i]);

			images.add(imageView);
		}

		// 文字
		titles = new String[] { "鞏俐不低俗，我就不能低俗", "撲樹又回來啦！再唱經典老歌引萬人大合唱",
				"揭祕北京電影如何升級", "樂視網TV版大派送", "熱血屌絲的反殺" };

		// 圓點
		dots = new ArrayList();
		dots.add(findViewById(R.id.dot_0));
		dots.add(findViewById(R.id.dot_1));
		dots.add(findViewById(R.id.dot_2));
		dots.add(findViewById(R.id.dot_3));
		dots.add(findViewById(R.id.dot_4));
	}

	private void initView() {
		viewPager = (ViewPager) findViewById(R.id.viewPager);
		title = (TextView) findViewById(R.id.title);

		title.setText(titles[0]);

		adapter = new MyPagerAdapter();
		viewPager.setAdapter(adapter);

		viewPager.setOnPageChangeListener(new MyOnPageChangeListener());
	}

	private class MyOnPageChangeListener implements OnPageChangeListener {

		@Override
		public void onPageScrollStateChanged(int arg0) {
			// TODO Auto-generated method stub

		}

		@Override
		public void onPageScrolled(int arg0, float arg1, int arg2) {
			// TODO Auto-generated method stub

		}

		@Override
		public void onPageSelected(int position) {
			// 記錄當前頁面
			currentIndex = position;
			// 文字更新
			title.setText(titles[position % images.size()]);
			// 圓點更新
			// 更新當前頁面為白色的圓點
			dots.get(position % images.size()).setBackgroundResource(
					R.drawable.dot_focused);
			// 更新上一個頁面為灰色的圓點
			dots.get(oldPosition % images.size()).setBackgroundResource(
					R.drawable.dot_normal);
			// 更新上一個頁面的位置
			oldPosition = position;
		}

	}

	private class MyPagerAdapter extends PagerAdapter {

		@Override
		public int getCount() {
			// return images.size();
			return Integer.MAX_VALUE;
		}

		// 判斷當前頁面顯示的資料 與 新頁面的資料是否相同
		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			// TODO Auto-generated method stub
			return arg0 == arg1;
		}

		// 初始化資料
		@Override
		public Object instantiateItem(ViewGroup viewPager, int position) {
			// TODO Auto-generated method stub
			// viewPager.addView(images.get(position));
			viewPager.addView(images.get(position % images.size()));
			return images.get(position % images.size());
		}

		// 銷燬資料
		@Override
		public void destroyItem(ViewGroup viewPager, int position, Object object) {
			// TODO Auto-generated method stub
			// super.destroyItem(container, position, object);

			viewPager.removeView(images.get(position % images.size()));
		}
	}

	@Override
	protected void onStart() {
		super.onStart();
		// 啟動切換圖片
		scheduledExecutor = Executors.newSingleThreadScheduledExecutor();
		scheduledExecutor.scheduleAtFixedRate(new MyPagerTask(), 2, 2,
				TimeUnit.SECONDS);
	}

	// 切換圖片任務類
	private class MyPagerTask implements Runnable {

		@Override
		public void run() {
			// 切換頁面
			// currentIndex = (currentIndex + 1) % images.size();
			currentIndex++;
			// viewPager.setCurrentItem(item);//設定當前頁面
			// 更新UI Handler
			handler.sendEmptyMessage(0);

		}
	}

	private Handler handler = new Handler() {

		@Override
		public void handleMessage(Message msg) {
			// super.handleMessage(msg);
			// 切換viewPager當前頁面
			viewPager.setCurrentItem(currentIndex);
		}
	};

	@Override
	protected void onStop() {
		super.onStop();
		// 停止切換圖片
		scheduledExecutor.shutdown();
	}

}