轮播图Viewpager支持手动滑动定时滑动和自动加载图片页数

首先来分析布局结构吧

外面是个FrameLayout 因为文字需要覆盖在image上面

接下来就是引入

    android.support.v4.view.ViewPager
    下面的文字和点用线性布局

main_layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<FrameLayout
android:id="@+id/fl"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<android.support.v4.view.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="190dp"/>

<LinearLayout
android:layout_marginTop="145dp"
android:gravity="center_vertical"
android:background="#66000000"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="45dp">
<TextView
android:id="@+id/title"
android:text="abcdefg ,hijklmn,opqrdt"
android:textColor="#ffffff"
android:maxLines="2"
android:ellipsize="end"
android:lineSpacingMultiplier="1.2"
android:gravity="center_vertical"
android:layout_marginLeft="5dp"
android:layout_weight="5"
android:layout_width="0dp"
android:layout_height="match_parent" />

<LinearLayout
android:id="@+id/dot_ll"
android:layout_weight="3"
android:orientation="horizontal"
android:gravity="end|bottom"
android:padding="9dp"
android:layout_width="0dp"
android:layout_height="match_parent">

</LinearLayout>
</LinearLayout>
</FrameLayout>
<ImageView
android:layout_below="@id/fl"
android:id="@+id/iv"
android:scaleType="center"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>

</RelativeLayout>

对了还有个点样式

<shape xmlns:android="http://schemas.android.com/apk/res/android"  android:shape="oval">
<solid android:color="#ffffff"/>
<corners android:radius="6dp"/>
</shape>

shape 形状
solid  线的 颜色
corners 半径

GSON 顺便提一下

比如json字符串为：[{"name":"name0","age":0}]

代码:

Person person = gson.fromJson(str, Person.class);

提供两个参数，分别是json字符串以及需要转换对象的类型。

第二种，转换成列表类型：

代码:

List<Person> ps = gson.fromJson(str, new TypeToken<List<Person>>(){}.getType());
for(int i =0; i < ps.size() ; i++)
{
Person p = ps.get(i);
System.out.println(p.toString());
}

那么开始步入主题了

分析
    实现滑动用到适配器pageradapter
    实现定时切换  可以用到handler定时发送消息 和timer定时器,等，这里我们就用handler
      还有一点，就是当滑到第一个还要向左滑动，让它切换到到最后一个，如何处理？同理最后    一个pager
    
    这里加载网络就用volley吧，为了方便因为这不是我们的重点

好了，上代码

public class MainActivity extends Activity {

private static final String url = "http://news-at.zhihu.com/api/4/news/latest";

private static final int MSG = 0x10 ;

private static final int MSG_SCROLL = 1;

private static final int  Defalut_postion= 100;

private static final int isError = 10000;

private  boolean  isScroll = true ;

private BannerAdapter bannerAdapter;

protected int mBannerPosition = 0;

private ImageView [] imgs;

private TextView tv_title;

private ViewPager pager;
private LinearLayout ll_dots;

public ImageLoader imageLoader = ImageLoader.getInstance();

@Override
public boolean onCreateOptionsMenu(Menu menu) {
//Added in the code by me for handling the init error
imageLoader.init(ImageLoaderConfiguration.createDefault(getBaseContext()));
return true;
}

private Handler handler = new Handler(){
private ItemText infoBean;
private List<Story> storyList;

@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
super.handleMessage(msg);
if (msg.what == MSG) {
infoBean = (ItemText) msg.obj;
storyList = infoBean.stories;
if(storyList.size() > 0 && storyList != null){
initAfterView(storyList);
}else{
tv_title.setText("郁闷。。网络有问题");
}

}
if (msg.what == MSG_SCROLL) {
Log.i("mBannerPosition","位置="+mBannerPosition);
if(isScroll){
int max = infoBean.stories.size();
Log.i("max","位置="+max);
int position =  (mBannerPosition + 1) % Defalut_postion;

if (position == max) { // 最后一页时回到第一页
pager.setCurrentItem(0, false);
}else{
Log.i("cuurrent","位置="+position);
pager.setCurrentItem(position);
}
if(storyList != null || storyList.size() == 0){
setTitle(storyList);
}else{
tv_title.setText("郁闷。。网络有问题");
}
handler.removeMessages(MSG_SCROLL);
handler.sendEmptyMessageDelayed(MSG_SCROLL, 2000);
}
}

if(msg.what == isError){
tv_title.setText("郁闷。。网络有问题");
}
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView iv =	(ImageView) findViewById(R.id.iv);
BitmapUtils mBitmapUtils = new BitmapUtils(this);
//mBitmapUtils.display(iv, "http://pic1.zhimg.com//6387f9f8cafb0719c15067a7f5659474.jpg");
init();
}

private void init() {
// TODO Auto-generated method stub

initView();

initData();

handler.sendEmptyMessageDelayed(MSG_SCROLL, 2000);

initEvent();
}

private void initEvent() {
pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}

@Override
public void onPageSelected(int position) {
mBannerPosition = position;
setIndicator(position);

}

@Override
public void onPageScrollStateChanged(int state) {

}
});

pager.setOnTouchListener(new View.OnTouchListener() {

@Override
public boolean onTouch(View arg0, MotionEvent arg1) {
// TODO Auto-generated method stub

if(arg1.getAction() == MotionEvent.ACTION_UP){
isScroll = true ;
handler.sendEmptyMessageDelayed(MSG_SCROLL, 2000);
}else {
isScroll = false ;
}
return false;
}
});
}

protected void setTitle2(int position) {
// TODO Auto-generated method stub

}

protected void setIndicator(int position) {
// TODO Auto-generated method stub
for (ImageView img : imgs) {
img.setBackgroundResource(R.drawable.dot_normal);
}
imgs[position].setBackgroundResource(R.drawable.dot_focused);
}

private void initView() {
pager = (ViewPager) findViewById(R.id.view_pager);
ll_dots = (LinearLayout) findViewById(R.id.dot_ll);

tv_title = (TextView) findViewById(R.id.title);

}

private void initDotas(List<Story> storyList) {
imgs = new ImageView[storyList.size()];
// TODO Auto-generated method stub
for (int i = 0; i < storyList.size(); i++) {
ImageView img = new ImageView(this);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(6,6);
params.rightMargin = 8;
img.setLayoutParams(params);
img.setBackgroundResource(R.drawable.dot_normal);
ll_dots.addView(img, params);
imgs[i] = img;
}

}

//  return jsonstr.substring(jsonstr.indexOf("{")).replace("\r\n","\n");
private void initData() {
Volley volley = new Volley();
RequestQueue queue = volley.newRequestQueue(this);
// TODO Auto-generated method stub
StringRequest request = new StringRequest(Request.Method.GET ,url, new Listener<String>() {
private String str;

@Override
public void onResponse(String response) {
try {
byte[] bytes = response.getBytes();
str = new String(bytes, "gb2312");
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(str != null){
ItemText  infoBean = new Gson().fromJson(str,ItemText.class );
Log.i("response", response);
Message message = new Message();
message.obj = infoBean;
message.what = 	MSG;
handler.sendMessage(message);
}else{
Message message = new Message();
message.what = 	isError;
handler.sendMessage(message);
}

}
}, new ErrorListener() {

@Override
public void onErrorResponse(VolleyError error) {
// TODO Auto-generated method stub

}
});
queue.add(request);
}

private void initAfterView(List<Story> storyList) {
bannerAdapter = new BannerAdapter(this ,storyList);
pager.setAdapter(bannerAdapter);
initDotas(storyList);
setTitle(storyList);
}

private void setTitle(List<Story> storyList) {

tv_title.setText(""+check(storyList.get(mBannerPosition).title));
Log.i("mBannerPositionsetTitle==", "=="+mBannerPosition);
Log.i("storyList.get(mBannerPosition).title", "=="+storyList.get(mBannerPosition).title);

}

private String check(String title) {
// TODO Auto-generated method stub
if(title == null)
return "";
else
return title;
}

}

adapter
public class BannerAdapter extends PagerAdapter {
private List<Story> bannerLsit;
private Context mContext ;
private BitmapUtils mBitmapUtils;
public  BannerAdapter(Context mContext ,List<Story> storyList){
this.mContext = mContext;
this.bannerLsit = storyList;
mBitmapUtils = new BitmapUtils(mContext);
}

@Override
public int getCount() {
// TODO Auto-generated method stub
return bannerLsit != null ? bannerLsit.size() : 0;
}

@Override
public boolean isViewFromObject(View arg0, Object arg1) {
// TODO Auto-generated method stub
return arg1 == arg0;
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
// TODO Auto-generated method stub
container.removeView((View) object);
}

@Override
public int getItemPosition(Object object) {
// TODO Auto-generated method stub
return POSITION_NONE;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
// TODO Auto-generated method stub
View view = LayoutInflater.from(mContext).inflate(R.layout.item, container, false);
ImageView iv = (ImageView) view.findViewById(R.id.image);
String abc = bannerLsit.get(position).images.get(0);
mBitmapUtils.display(iv,bannerLsit.get(position).images.get(0));
container.addView(view);
return view;
}

@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
// TODO Auto-generated method stub
super.unregisterDataSetObserver(observer);
}

@Override
public void notifyDataSetChanged() {
// TODO Auto-generated method stub
super.notifyDataSetChanged();
}

@Override
public void registerDataSetObserver(DataSetObserver observer) {
// TODO Auto-generated method stub
super.registerDataSetObserver(observer);
}

@Override
public void finishUpdate(ViewGroup container) {
// TODO Auto-generated method stub
super.finishUpdate(container);
}
}