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。

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 weiboList = null;

public WeiboAdapter(HomeActivity homeActivity, ArrayList 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> imageCache;

public AsyncImageLoader() {

imageCache = new HashMap>();

}

public Drawable loadDrawable(final String imageUrl, final ImageView imageView, final ImageCallback imageCallback) {

if (imageCache.containsKey(imageUrl)) {

//从缓存中获取

SoftReference 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));

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：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。