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;
}
}
}