Android ViewPager 实现多个页面切换滑动
使用ViewPager这个类可以轻松实现多个页面的滑动功能，而且相对viewgroup来讲要简单容易一些，在此之前我们需要导入android-support-v4.jar这个jar包，是google提供的扩展包，位置路径为android-sdk-windows\extras\android\support\v4\android-support-v4.jar，如果没有找到，需要打开Android SDK Manager在Extras中进行下载，最后记得引入工程中并build path。
在本示例中，我参考了几个demo整理出来的viewpager的最基本用法，制作了一个类似新闻导航功能的界面，每个页面的下方有对应的项目符号，当页面进行切换的时候项目符号也随之变化，下面是实现后的图片：
java代码：
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.ViewGroup.LayoutParams;
import android.view.Window;
import android.widget.ImageView;
public class ViewPagerGuideActivity extends Activity {
private ViewPager viewPager;
/**装分页显示的view的数组*/
private ArrayList<View> pageViews;
private ImageView imageView;
/**将小圆点的图片用数组表示*/
private ImageView[] imageViews;
//包裹滑动图片的LinearLayout
private ViewGroup viewPics;
//包裹小圆点的LinearLayout
private ViewGroup viewPoints;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);//设置无标题栏
//将要分页显示的View装入数组中
LayoutInflater inflater = getLayoutInflater();
pageViews = new ArrayList<View>();
pageViews.add(inflater.inflate(R.layout.page01, null));
pageViews.add(inflater.inflate(R.layout.page02, null));
pageViews.add(inflater.inflate(R.layout.page03, null));
//创建imageviews数组，大小是要显示的图片的数量
imageViews = new ImageView[pageViews.size()];
//从指定的XML文件加载视图
viewPics = (ViewGroup) inflater.inflate(R.layout.view_pics, null);
//实例化小圆点的linearLayout和viewpager
viewPoints = (ViewGroup) viewPics.findViewById(R.id.viewGroup);
viewPager = (ViewPager) viewPics.findViewById(R.id.guidePages);
//添加小圆点的图片
for(int i=0;i<pageViews.size();i++){
imageView = new ImageView(ViewPagerGuideActivity.this);
//设置小圆点imageview的参数
imageView.setLayoutParams(new LayoutParams(20,20));//创建一个宽高均为20 的布局
imageView.setPadding(20, 0, 20, 0);
//将小圆点layout添加到数组中
imageViews[i] = imageView;
//默认选中的是第一张图片，此时第一个小圆点是选中状态，其他不是
if(i==0){
imageViews[i].setBackgroundResource(R.drawable.page_indicator_focused);
}else{
imageViews[i].setBackgroundResource(R.drawable.page_indicator);
}
//将imageviews添加到小圆点视图组
viewPoints.addView(imageViews[i]);
}
//显示滑动图片的视图
setContentView(viewPics);
//设置viewpager的适配器和监听事件
viewPager.setAdapter(new GuidePageAdapter());
viewPager.setOnPageChangeListener(new GuidePageChangeListener());
}
class GuidePageAdapter extends PagerAdapter{
//销毁position位置的界面
@Override
public void destroyItem(View v, int position, Object arg2) {
// TODO Auto-generated method stub
((ViewPager)v).removeView(pageViews.get(position));
}
@Override
public void finishUpdate(View arg0) {
// TODO Auto-generated method stub
}
//获取当前窗体界面数
@Override
public int getCount() {
// TODO Auto-generated method stub
return pageViews.size();
}
//初始化position位置的界面
@Override
public Object instantiateItem(View v, int position) {
// TODO Auto-generated method stub
((ViewPager) v).addView(pageViews.get(position));
return pageViews.get(position);
}
// 判断是否由对象生成界面
@Override
public boolean isViewFromObject(View v, Object arg1) {
// TODO Auto-generated method stub
return v == arg1;
}
@Override
public void startUpdate(View arg0) {
// TODO Auto-generated method stub
}
@Override
public int getItemPosition(Object object) {
// TODO Auto-generated method stub
return super.getItemPosition(object);
}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
// TODO Auto-generated method stub
}
@Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
}
}
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 position) {
// TODO Auto-generated method stub
for(int i=0;i<imageViews.length;i++){
imageViews[position].setBackgroundResource(R.drawable.page_indicator_focused);
//不是当前选中的page，其小圆点设置为未选中的状态
if(position !=i){
imageViews[i].setBackgroundResource(R.drawable.page_indicator);
}
}
}
}
}
主页面的布局：
<?xml version="1.0" encoding="utf-8"?><FrameLayout 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/linearLayout1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <include layout="@layout/page_header"/> <android.support.v4.view.ViewPager android:id="@+id/guidePages" android:layout_width="fill_parent" android:layout_height="wrap_content"/> </LinearLayout> <LinearLayout android:id="@+id/linearLayout2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <RelativeLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <LinearLayout android:id="@+id/viewGroup" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_marginBottom="40dp" android:gravity="center_horizontal" android:orientation="horizontal"> </LinearLayout> </RelativeLayout> </LinearLayout> </FrameLayout> |
标题栏的布局：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:background="@drawable/title" android:gravity="center_vertical" > <Button android:id="@+id/btn_left" android:layout_width="80dp" android:layout_height="30dp" android:text="返回" android:textSize="15sp" android:textColor="@android:color/white" android:background="@drawable/header_btn" android:layout_margin="5dp"/> <TextView android:id="@+id/tvTitle" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="奥运快报" android:textSize="18sp" android:layout_weight="1" android:ellipsize="end" android:gravity="center_horizontal"/> <Button android:id="@+id/btn_right" android:layout_width="80dp" android:layout_height="30dp" android:text="首页" android:textSize="15sp" android:textColor="@android:color/white" android:background="@drawable/header_btn" android:layout_margin="5dp"/></LinearLayout> |
子页面的布局：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="@android:color/white" > <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content"> <ImageView android:layout_width="fill_parent" android:layout_height="wrap_content" android:src="@drawable/pic_lindan"/> </LinearLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:layout_marginBottom="10dp" android:layout_marginLeft="30dp" android:layout_marginRight="30dp" android:background="@drawable/divider_horizontal_line"> </LinearLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginRight="30dp" android:layout_marginLeft="30dp" android:textColor="@android:color/black" android:text="@string/string_lindan"/> </LinearLayout> </LinearLayout> |
