关于viewPager matrix 计算 ，现在记录下来

package com.vmei.activity;

import java.util.ArrayList;
import java.util.Currency;
import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.vmei.R;
import com.vmei.view.BaseView;
import com.vmei.view.IncomeDayView;
import com.vmei.view.IncomeMonthView;
import com.vmei.view.IncomeWeekView;

public class IncomeAllActivity extends Activity implements OnClickListener {
	private ViewPager mPager;// 页卡内容
	private List<BaseView> listViews; // Tab页面列表
	private ImageView cursor;// 动画图片
	private TextView tv_income_day, tv_income_week, tv_income_month;// 页卡头标
	private int offset = 0;// 动画图片偏移量
	private int currIndex = 0;// 当前页卡编号
	private int bmpW;// 动画图片宽度

	private RelativeLayout rl_return;
	private int sign;// 默认选中页面的标识
	private int screenW;// 获取分辨率宽度
	private int x;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_income_all);
		Intent intent = getIntent();
		sign = intent.getExtras().getInt("sign");// 默认选中页面的标识
		sign=1;
		InitImageView();
		InitTextView();
		InitViewPager();
	}

	/**
	 * 初始化头标。
	 */
	private void InitTextView() {

		tv_income_day = (TextView) findViewById(R.id.tv_income_day);
		tv_income_week = (TextView) findViewById(R.id.tv_income_week);
		tv_income_month = (TextView) findViewById(R.id.tv_income_month);
		rl_return = (RelativeLayout) findViewById(R.id.rl_return);
		rl_return.setVisibility(View.VISIBLE);
		rl_return.setOnClickListener(this);

		tv_income_day.setOnClickListener(new MyOnClickListener(0));
		tv_income_week.setOnClickListener(new MyOnClickListener(1));
		tv_income_month.setOnClickListener(new MyOnClickListener(2));
	}

	/**
	 * 初始化ViewPager页面
	 */
	@SuppressWarnings("rawtypes")
	private void InitViewPager() {
		mPager = (ViewPager) findViewById(R.id.vPager);

		listViews = new ArrayList<BaseView>();

		listViews.add(new IncomeDayView(this));
		listViews.add(new IncomeWeekView(this));
		listViews.add(new IncomeMonthView(this));

		mPager.setAdapter(new MyPagerAdapter(listViews));
		mPager.setCurrentItem(sign);// 设置默认选中页面
		currIndex=sign;
		mPager.setOnPageChangeListener(new MyOnPageChangeListener());
	}

	/**
	 * 初始化滑动切换页面动画
	 */
	private void InitImageView() {
		cursor = (ImageView) findViewById(R.id.cursor);
		bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.a).getWidth();// 获取图片宽度
		DisplayMetrics dm = new DisplayMetrics();
		getWindowManager().getDefaultDisplay().getMetrics(dm);
		screenW = dm.widthPixels;
		x = (screenW / 3 - bmpW) / 2;
		offset = sign*screenW/3 +x;// 计算偏移量
		Matrix matrix = new Matrix();
		matrix.postTranslate(offset, 0);
		
		
		/*int offset = (GloableParameters.WIN_W / 3 - strip.getWidth()) / 2;

		Matrix matrix = new Matrix();
		matrix.postTranslate(offset, 0);// 设置图片的位置
*/		cursor.setImageMatrix(matrix);// 设置动画初始位置
	}

	/**
	 * ViewPager适配器
	 */
	public class MyPagerAdapter extends PagerAdapter {
		public List<BaseView> mListViews;

		public MyPagerAdapter(List<BaseView> mListViews) {
			this.mListViews = mListViews;
		}

		@Override
		public void destroyItem(View arg0, int arg1, Object arg2) {
			((ViewPager) arg0).removeView(mListViews.get(arg1).getRootView());
		}

		@Override
		public void finishUpdate(View arg0) {
		}

		@Override
		public int getCount() {
			return mListViews.size();
		}

		@Override
		public Object instantiateItem(View arg0, int arg1) {
			((ViewPager) arg0).addView(mListViews.get(arg1).getRootView(), 0);
			return mListViews.get(arg1).getRootView();
		}

		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			return arg0 == (arg1);
		}

		@Override
		public void restoreState(Parcelable arg0, ClassLoader arg1) {
		}

		@Override
		public Parcelable saveState() {
			return null;
		}

		@Override
		public void startUpdate(View arg0) {
		}
	}

	/**
	 * 头标点击监听
	 */
	public class MyOnClickListener implements View.OnClickListener {
		private int index = 0;

		public MyOnClickListener(int i) {
			index = i;
		}

		@Override
		public void onClick(View v) {
			mPager.setCurrentItem(index);
		}
	};

	/**
	 * 页卡切换监听
	 */
	public class MyOnPageChangeListener implements OnPageChangeListener {

		//int one = offset * 2 + bmpW;// 页卡1 -> 页卡2 偏移量
		int one =screenW / 3;// 页卡1 -> 页卡2 偏移量
		int two = one * 2;// 页卡1 -> 页卡3 偏移量

		@Override
		public void onPageSelected(int arg0) {
			Animation animation = null;
			int totalPage=3;
			//x = (screenW / 3 - bmpW) / 2;
		if(sign==0){
			 animation = new TranslateAnimation(currIndex * screenW / 3, arg0
						* screenW / 3, 0, 0);
				
		}else if(sign==2){
			///int temp=totalPage-arg0;
			//currIndex=2  arg0=1
			//currIndex=1 arg0=0;
			//currIndex=0 arg0=1
			 animation = new TranslateAnimation(-(totalPage-currIndex-1) * screenW / 3, -(totalPage-arg0-1)
						* screenW / 3, 0, 0);
			 
		}else if(sign==1){
			//currIndex=1 arg0=0
			//currIndex=0 arg0=1
			 animation = new TranslateAnimation(-(totalPage-currIndex-2) * screenW / 3, -(totalPage-arg0-2)* screenW / 3, 0, 0);
		}
			
			animation.setFillAfter(true);// True:图片停在动画结束位置
			animation.setDuration(300);
			cursor.startAnimation(animation);
			currIndex = arg0;
		}

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

		@Override
		public void onPageScrollStateChanged(int arg0) {
		}
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.rl_return:
			finish();
			break;
		}
	}
}