[android]简单方法记载 在adapter中异步加载网络图片
16lz
2021-01-23
/** * @param url 本地或网络的url * @return url的bitmap */public static Bitmap getLocalOrNetBitmap(String url) { Bitmap bitmap = BitmapFactory.decodeResource(sContext.getResources(), R.drawable.store_item_default);if (url != null) { InputStream in = null; BufferedOutputStream out = null; try { //读取图片输入流 in = new BufferedInputStream(new URL(url).openStream(), 2 * 1024); //准备输出流 final ByteArrayOutputStream dataStream = new ByteArrayOutputStream(); out = new BufferedOutputStream(dataStream, 2 * 1024); byte[] b = new byte[1024]; int read; //将输入流变为输出流 while ((read = in.read(b)) != -1) { out.write(b, 0, read); } out.flush(); //将输出流转换为bitmap byte[] data = dataStream.toByteArray(); bitmap = BitmapFactory.decodeByteArray(data, 0, data.length); data = null; return bitmap; } catch (IOException e) { e.printStackTrace(); return bitmap; } } return bitmap; }异步获取，保证不阻塞主线程
private void asyncloadImage(final ImageView imageView, final String uri) { final Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (msg.what == 1) { Bitmap bitmap = (Bitmap) msg.obj; if (imageView != null && uri != null) { imageView.setImageBitmap(bitmap); } } } }; // 子线程，开启子线程去下载或者去缓存目录找图片，并且返回图片在缓存目录的地址 Runnable runnable = new Runnable() { @Override public void run() { try { //这个URI是图片下载到本地后的缓存目录中的URI if (uri != null ) { Bitmap bitmap = getLocalOrNetBitmap(uri); Message msg = new Message(); msg.what = 1; msg.obj = bitmap; mHandler.sendMessage(msg); } } catch (Exception e) { e.printStackTrace(); } } }; new Thread(runnable).start(); }}在adapter中的getview
@Overridepublic View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder; if (convertView == null) { convertView = mInflater.inflate(R.layout.mission_itemview, null); holder = new ViewHolder(); /**得到各个控件的对象*/ holder.icon = (ImageView) convertView.findViewById(R.id.mission_pre_img); convertView.setTag(holder); //绑定ViewHolder对象 } else { holder = (ViewHolder) convertView.getTag(); //取出ViewHolder对象 } /**设置TextView显示的内容，即我们存放在动态数组中的数据*/ asyncloadImage(holder.icon, mList.get(position).mAdvdefInfo3.mIcon); return convertView;}更多相关文章
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