本文的目的是要实现左右滑动的指引效果。那么什么是指引效果呢？现在的应用为了有更好的用户体验，一般会在应用开始显示一些指引帮助页面，使用户能更好的理解应用的功能，甚至是一些新闻阅读器会把一些头条新闻以指引效果的形式显示。说个最基本的，就是我们的手机主屏幕就是这种效果。
下面我们就开始实现我们的左右滑动指引效果。为了大家更好的理解，我们先看下实现效果，如下图所示：
在这里，我们需要用到google提到的一个包——android-support-v4.jar，这个包是为了方便实现android view之间的切换，关于android-support-v4.jar的详细信息，大家可以访问google官方网站：http://developer.android.com/sdk/compatibility-library.html
首先我们先看下项目结构：
核心实现代码如下所示：
package com.test.guide;
import java.util.ArrayList;import android.app.Activity;
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.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
/**
* Android实现左右滑动指引效果
* @Description: Android实现左右滑动指引效果
* @File: MyGuideViewActivity.java
* @Package com.test.guide
* @Author Hanyonglu
* @Date 2012-4-6 下午11:15:18
* @Version V1.0
*/
public class MyGuideViewActivity extends Activity {
private ViewPager viewPager;
private ArrayList<View> pageViews;
private ImageView imageView;
private ImageView[] imageViews;
// 包裹滑动图片LinearLayout
private ViewGroup main;
// 包裹小圆点的LinearLayout
private ViewGroup group;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 设置无标题窗口
requestWindowFeature(Window.FEATURE_NO_TITLE);
LayoutInflater inflater = getLayoutInflater();
pageViews = new ArrayList<View>();
pageViews.add(inflater.inflate(R.layout.item05, null));
pageViews.add(inflater.inflate(R.layout.item06, null));
pageViews.add(inflater.inflate(R.layout.item01, null));
pageViews.add(inflater.inflate(R.layout.item02, null));
pageViews.add(inflater.inflate(R.layout.item03, null));
pageViews.add(inflater.inflate(R.layout.item04, null));
imageViews = new ImageView[pageViews.size()];
main = (ViewGroup)inflater.inflate(R.layout.main, null);
group = (ViewGroup)main.findViewById(R.id.viewGroup);
viewPager = (ViewPager)main.findViewById(R.id.guidePages);
for (int i = 0; i < pageViews.size(); i++) {
imageView = new ImageView(MyGuideViewActivity.this);
imageView.setLayoutParams(new LayoutParams(20,20));
imageView.setPadding(20, 0, 20, 0);
imageViews[i] = imageView;
if (i == 0) {
//默认选中第一张图片
imageViews[i].setBackgroundResource(R.drawable.page_indicator_focused);
} else {
imageViews[i].setBackgroundResource(R.drawable.page_indicator);
}
group.addView(imageViews[i]);
}
setContentView(main);
viewPager.setAdapter(new GuidePageAdapter());
viewPager.setOnPageChangeListener(new GuidePageChangeListener());
}
// 指引页面数据适配器
class GuidePageAdapter extends PagerAdapter {
@Override
public int getCount() {
return pageViews.size();
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
@Override
public int getItemPosition(Object object) {
// TODO Auto-generated method stub
return super.getItemPosition(object);
}
@Override
public void destroyItem(View arg0, int arg1, Object arg2) {
// TODO Auto-generated method stub
((ViewPager) arg0).removeView(pageViews.get(arg1));
}
@Override
public Object instantiateItem(View arg0, int arg1) {
// TODO Auto-generated method stub
((ViewPager) arg0).addView(pageViews.get(arg1));
return pageViews.get(arg1);
}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
// TODO Auto-generated method stub
}
@Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
}
@Override
public void startUpdate(View arg0) {
// TODO Auto-generated method stub
}
@Override
public void finishUpdate(View arg0) {
// TODO Auto-generated method stub
}
}
// 指引页面更改事件监听器
class GuidePageChangeListener 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 arg0) {
for (int i = 0; i < imageViews.length; i++) {
imageViews[arg0].setBackgroundResource(R.drawable.page_indicator_focused);
if (arg0 != i) {
imageViews[i].setBackgroundResource(R.drawable.page_indicator);
}
}
}
}
}
item.xml代码如下：
<?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:orientation="vertical" >
<LinearLayout
android:id="@+id/linearLayout01"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout02"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:background="@drawable/divider_horizontal_line">
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/feature_guide_0" >
</ImageView>
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:background="@drawable/bg" >
<LinearLayout
android:id="@+id/linearLayout2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_marginTop="30px"
android:layout_marginBottom="30px"
android:layout_marginLeft="30px"
android:layout_marginRight="30px"
android:background="@drawable/divider_horizontal_line" >
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#000000"
android:paddingLeft="30px"
android:paddingRight="30px"
android:text="@string/text1" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
以上便是实现大概步骤，由于网速问题，代码我将会很快，敬请关注……。