先贴效果图(每个开关Tab债券。尾随页变化。效果图蓝条添加的用户体验)

ViewPager实现页面切换_偏移量

首先看总体效果图的布局文件吧(非常easy,就三部分,各自是Tab栏目、定位蓝条、各个页面(是V4包下的ViewPager))

activity_tab_winter_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:umadsdk="http://schemas.android.com/apk/res/com.LoveBus"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FF969696"
android:orientation="vertical" >

<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="45.0dip"
android:background="#FFDFD7D7" >

<TextView
android:id="@+id/text1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="\n广告"
android:textColor="#000000" />

<TextView
android:id="@+id/text2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="\n选项"
android:textColor="#000000" />

<TextView
android:id="@+id/text3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:gravity="center"
android:text="\n关于作者"
android:textColor="#000000" />
</LinearLayout>

<ImageView
android:id="@+id/cursor"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:scaleType="matrix"
android:src="@drawable/icon_tab_winter_a" />


<android.support.v4.view.ViewPager
android:id="@+id/vPager"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:layout_gravity="center"
android:layout_weight="1.0"
android:background="#FFDFD7D7"
android:flipInterval="30"
android:persistentDrawingCache="animation" />

</LinearLayout>

接下来贴出每一个页面的布局文件

activity_tab_winter_lay1.xml--activity_tab_winter_lay2.xml---activity_tab_winter_lay3.xml(三个页面是一样的,就是text内容不一样。这样好区分)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#FFDFD7D7"
android:orientation="vertical" >

<Button
android:id="@+id/btn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="广告" />
</LinearLayout>


MainActivity(思路简单,代码有凝视)

package com.example.viewpagerdemo;

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

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
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.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.TranslateAnimation;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {
private ViewPager mPager;// 页卡内容
private List<View> listViews; // Tab页面列表

private TextView t1, t2, t3;// 页卡头标
private int currIndex = 0;// 当前页卡编号

private ImageView cursor;// 动绘图片
private int bmpW;// 动绘图片宽度
private int offset = 0;// 动绘图片偏移量

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tab_winter_main);
//初始化三部分
InitImageView();
InitTextView();
InitViewPager();
}
/**
* 初始化动画
*/
private void InitImageView() {
//获取空间
cursor = (ImageView) findViewById(R.id.cursor);
// 获取图片宽度
bmpW = BitmapFactory.decodeResource(getResources(),
R.drawable.icon_tab_winter_a).getWidth();
//得到屏幕宽度
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
int screenW = dm.widthPixels;
// 计算偏移量
offset = (screenW / 3 - bmpW) / 2;
Matrix matrix = new Matrix();
matrix.postTranslate(offset, 0);
// 设置动画初始位置
cursor.setImageMatrix(matrix);
}
/**
* 初始化头标
*/
private void InitTextView() {
t1 = (TextView) findViewById(R.id.text1);
t2 = (TextView) findViewById(R.id.text2);
t3 = (TextView) findViewById(R.id.text3);

//加入监听事件
t1.setOnClickListener(new MyOnClickListener(0));
t2.setOnClickListener(new MyOnClickListener(1));
t3.setOnClickListener(new MyOnClickListener(2));
}

/**
* 初始化ViewPager
*/
private void InitViewPager() {
//viewPager
mPager = (ViewPager) findViewById(R.id.vPager);
//data
listViews = new ArrayList<View>();
LayoutInflater mInflater = getLayoutInflater();
listViews.add(mInflater
.inflate(R.layout.activity_tab_winter_lay2, null));
listViews.add(mInflater
.inflate(R.layout.activity_tab_winter_lay1, null));
listViews.add(mInflater
.inflate(R.layout.activity_tab_winter_lay3, null));
//adapter
mPager.setAdapter(new MyPagerAdapter(listViews));
mPager.setCurrentItem(0);
//监听事件
mPager.setOnPageChangeListener(new MyOnPageChangeListener());
}



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

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

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

@Override
public void finishUpdate(View arg0) {
}

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

@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(mListViews.get(position));
return mListViews.get(position);
}

@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;
}

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 two = one * 2;// 页卡1 -> 页卡3 偏移量

public void onPageSelected(int position) {
Animation animation = null;
switch (position) {
case 0:
if (currIndex == 1) {
animation = new TranslateAnimation(one, 0, 0, 0);
} else if (currIndex == 2) {
animation = new TranslateAnimation(two, 0, 0, 0);
}
break;
case 1:
if (currIndex == 0) {
animation = new TranslateAnimation(offset, one, 0, 0);
} else if (currIndex == 2) {
animation = new TranslateAnimation(two, one, 0, 0);
}
break;
case 2:
if (currIndex == 0) {
animation = new TranslateAnimation(offset, two, 0, 0);
} else if (currIndex == 1) {
animation = new TranslateAnimation(one, two, 0, 0);
}
break;
}
currIndex = position;
animation.setFillAfter(true);
animation.setDuration(300);
cursor.startAnimation(animation);
}

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

public void onPageScrollStateChanged(int arg0) {
}
}
}