常用的android权限配置和常用工具代码
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4、从网络上获取文件，存储在指定的缓存目录下
/** * 先把网络文件的fileUri进行MD5加密处理，然后生产对应的文件（后缀名不变） * 先从缓存目录下查询是否存在该文件，如果不存在则再次获取，直接从缓存中获取 * 否则把网络文件缓存到本地 * @param fileUri * @param cacheDir * @return * @throws Exception */public Uri getImage(String fileUri, File cacheDir) throws Exception{String tempPath = MD5.getMD5(fileUri) + fileUri.substring(fileUri.lastIndexOf("."));File localFile = new File(cacheDir, tempPath);if(localFile.exists()){return Uri.fromFile(localFile);}else{HttpURLConnection conn = (HttpURLConnection)new URL(fileUri).openConnection();conn.setConnectTimeout(5000);conn.setRequestMethod("GET");if(conn.getResponseCode() == 200){FileOutputStream outStream = new FileOutputStream(localFile);InputStream inputStream = conn.getInputStream();byte[] buffer = new byte[1024];int len = 0;while( (len = inputStream.read(buffer)) != -1){outStream.write(buffer, 0, len);}inputStream.close();outStream.close();return Uri.fromFile(localFile);}}return null;}?