Android仿新浪微博自定义ListView下拉刷新(4)
自定义PullToRefreshListView继承ListView，在ListView头部添加一个下拉的头部布局。跟ListView用法完全一致。
该自定义Listview代码详解具体可参考： //www.jb51.net/article/97845.htm
此处详细介绍Adapter的详细代码。
1.首先给Adapter绑定ListView布局。
2.其次创建一个层次对应组件的类，将对应的组件和对象进行关联，提高效率。
3.然后跟陆获得的图片路径异步下载图片，由于不知道该微博图片的数量，所以在listview中添加一个GirlView控件或者GirlLayout布局，然后将得到的图片添加到其中，并按指定属性值排列好。
**
* Created by D&LL on 2016/6/2.
*/
public class WeiboAdapter extends BaseAdapter {
/**
* 为提高效率，缓存数据准备的一个自定义类 对应一条微博数据
*/
class WeiboHolder {
public ImageView wbicon;
public TextView wbtext, wbtime, wbuser;
}
private HomeActivity homeActivity = null;
//数据集
public ArrayList<WeiBoInfo> weiboList = null;
public WeiboAdapter(HomeActivity homeActivity, ArrayList<WeiBoInfo> weiboList) {
this.homeActivity = homeActivity;
this.weiboList = weiboList;
}
//微博图片的异步下载类
AsyncImageLoader asyncImageLoader;
@Override
public View getView(int position, View convertView, ViewGroup parent) {
asyncImageLoader = new AsyncImageLoader();
//记载微博的每条需要显示在什么布局上的布局对象
convertView = LayoutInflater.from(this.homeActivity.getApplicationContext()).inflate(R.layout.listview,
null);
//创建一个层次对应组件的类
WeiboHolder wh = new WeiboHolder();
//将对应的组件和对象进行关联，提高效率
wh.wbicon = (ImageView) convertView.findViewById(R.id.wbicon);
wh.wbtext = (TextView) convertView.findViewById(R.id.wbtext);
wh.wbtime = (TextView) convertView.findViewById(R.id.wbtime);
wh.wbuser = (TextView) convertView.findViewById(R.id.wbuser);
/* wh.wbimage = (ImageView) convertView.findViewById(R.id.wbimage);*/
//获得一条微博数据
WeiBoInfo wb = this.weiboList.get(position);
if (wb != null) {
convertView.setTag(wb.getId());
wh.wbuser.setText(wb.getUserName());
wh.wbtime.setText(wb.getTime());
wh.wbtext.setText(StringUtils.getEmotionContent(convertView.getContext(), wh.wbtext, wb.getText()
), TextView.BufferType.SPANNABLE);
if (wb.getHaveImage()) {
// 是否有图片信息
//异步加载图片内容
Drawable[] wb_image = new Drawable[wb.getImage_context().length];
ImageView[] wbimage = new ImageView[wb.getImage_context().length];
GridLayout layout = (GridLayout) convertView.findViewById(R.id.imagelayout);
//遍历下载所有图片 并添加到listview中
for (int i = 0; i < wb.getImage_context().length; i++) {
wbimage[i] = new ImageView(this.homeActivity.getApplicationContext());
wbimage[i].setPadding(5, 5, 5, 5);
wbimage[i].setScaleType(ImageView.ScaleType.FIT_XY);
GridLayout.Spec row = GridLayout.spec(i / 3);
GridLayout.Spec colum = GridLayout.spec(i % 3);
GridLayout.LayoutParams params = new GridLayout.LayoutParams(row, colum);
params.setGravity(Gravity.FILL);
params.width = 250;
params.height = 250;
wb_image[i] = asyncImageLoader.loadDrawable(wb.getImage_context()[i],
wbimage[i], new AsyncImageLoader.ImageCallback() {
@Override
public void imageLoaded(Drawable imageDrawable, ImageView imageView, String imageUrl) {
imageView.setImageDrawable(imageDrawable);
}
});
wbimage[i].setImageDrawable(wb_image[i]);
layout.addView(wbimage[i], params);
}
}
//异步加载用户头像数据
Drawable cachedImage = asyncImageLoader.loadDrawable(wb.getUserIcon(), wh.wbicon, new AsyncImageLoader.ImageCallback() {
@Override
public void imageLoaded(Drawable imageDrawable, ImageView imageView, String imageUrl) {
imageView.setImageDrawable(imageDrawable);
}
});
if (cachedImage == null) {
} else {
wh.wbicon.setImageDrawable(cachedImage);
}
}
return convertView;
}
@Override
public int getCount() {
return this.weiboList.size();
}
@Override
public Object getItem(int position) {
return this.weiboList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
}
异步下载图片的方法。使用SoftReference是软引用，是为了系统更好的回收变量；从缓存中获取图片路径后，建立新一个新的线程下载图片。
**
* Created by D&LL on 2016/6/2.
*/
public class AsyncImageLoader {
//SoftReference是软引用，是为了更好的为了系统回收变量
private HashMap<String, SoftReference<Drawable>> imageCache;
public AsyncImageLoader() {
imageCache = new HashMap<String, SoftReference<Drawable>>();
}
public Drawable loadDrawable(final String imageUrl, final ImageView imageView, final ImageCallback imageCallback) {
if (imageCache.containsKey(imageUrl)) {
//从缓存中获取
SoftReference<Drawable> softReference = imageCache.get(imageUrl);
Drawable drawable = softReference.get();
if (drawable != null) {
return drawable;
}
}
final Handler handler = new Handler() {
public void handleMessage(Message message) {
imageCallback.imageLoaded((Drawable) message.obj, imageView, imageUrl);
}
};
//建立新一个新的线程下载图片
new Thread() {
@Override
public void run() {
Drawable drawable = loadImageFromUrl(imageUrl);
imageCache.put(imageUrl, new SoftReference<Drawable>(drawable));
Message message = handler.obtainMessage(0, drawable);
handler.sendMessage(message);
}
}.start();
return null;
}
public static Drawable loadImageFromUrl(String url) {
URL m;
InputStream i = null;
try {
m = new URL(url);
i = (InputStream) m.getContent();
} catch (MalformedURLException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Drawable d = Drawable.createFromStream(i, "src");
return d;
}
//回调接口
public interface ImageCallback {
public void imageLoaded(Drawable imageDrawable, ImageView imageView, String imageUrl);
}
}
效果图：
