19 Android简单示例

最后更新于:2022-04-01 02:50:25

# Andriod简单示例 由于在某些嵌入式系统中使用的是Android系统,这里给出一个简单的Android App的示例,具体代码可以从clone自[https://github.com/phodal/iot-android](https://github.com/phodal/iot-android) 代码说明,经过测试的版本有 * Android 2.3 * Android 4.0.4 机型有 * HTC G1 (android 2.3) * Motor xt300 (android 2.3) * Sony ST25I (android 4.0.4) * MI2 应该可以在大部分的手机上工作。 ## 调用Web Services GET 这里我们参考一篇文章来调用Web Services——[Calling Web Services in Android using HttpClient](http://lukencode.com/2010/04/27/calling-web-services-in-android-using-httpclient/) ### 创建RESTClient 在这里我们首先会定义四个REST方法GET、POST、PUT、DELETE ~~~ public void Execute(RequestMethod method) throws Exception { switch (method) { case GET: { // add parameters String combinedParams = ""; if (!params.isEmpty()) { combinedParams += "?"; for (NameValuePair p : params) { String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue(), HTTP.UTF_8); if (combinedParams.length() > 1) { combinedParams += "&" + paramString; } else { combinedParams += paramString; } } } HttpGet request = new HttpGet(url + combinedParams); request.addHeader("Accept-Encoding", "gzip"); // add headers for (NameValuePair h : headers) { request.addHeader(h.getName(), h.getValue()); } executeRequest(request, url); break; } case POST: { HttpPost request = new HttpPost(url); request.addHeader("Accept-Encoding", "gzip"); // add headers for (NameValuePair h : headers) { request.addHeader(h.getName(), h.getValue()); } if (!data.equals("")) { request.setEntity(new StringEntity(data, HTTP.UTF_8)); } if (!params.isEmpty()) { request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8)); } executeRequest(request, url); break; } case PUT: { HttpPut request = new HttpPut(url); request.addHeader("Accept-Encoding", "gzip"); // add headers for (NameValuePair h : headers) { request.addHeader(h.getName(), h.getValue()); } if (!data.equals("")) { request.setEntity(new StringEntity(data, HTTP.UTF_8)); } if (!params.isEmpty()) { request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8)); } executeRequest(request, url); break; } case DELETE: { HttpDelete request = new HttpDelete(url); request.addHeader("Accept-Encoding", "gzip"); // add headers for (NameValuePair h : headers) { request.addHeader(h.getName(), h.getValue()); } executeRequest(request, url); break; } } } ~~~ 这四个方法最后都执行executeRequest来获取响应结果。 ~~~ protected void executeRequest(HttpUriRequest request, String url) { HttpParams httpParameters = new BasicHttpParams(); HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection); HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket); HttpProtocolParams.setUseExpectContinue(httpParameters, false); request.setParams(httpParameters); setOauth(request); DefaultHttpClient client = new DefaultHttpClient(); HttpResponse httpResponse; try { httpResponse = client.execute(request); responseCode = httpResponse.getStatusLine().getStatusCode(); message = httpResponse.getStatusLine().getReasonPhrase(); HttpEntity entity = httpResponse.getEntity(); if (entity != null) { InputStream instream = httpResponse.getEntity().getContent(); Header contentEncoding = httpResponse .getFirstHeader("Content-Encoding"); if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) { instream = new GZIPInputStream(instream); } // instream = entity.getContent(); response = convertStreamToString(instream); // Closing the input stream will trigger connection release instream.close(); } } catch (ClientProtocolException e) { client.getConnectionManager().shutdown(); e.printStackTrace(); } catch (IOException e) { client.getConnectionManager().shutdown(); e.printStackTrace(); } } ~~~ 接着,我们便可以执行getResponse()函数来获取结果。 ## 使用REST Client获取结果 使用RESTClient时,便可以用下面的示例 ~~~ RestClient client = new RestClient(tUrl); try { client.Execute(RequestMethod.GET); if (client.getResponseCode() != 200) { //do something } //JSONArray jArray = new JSONArray(client.getResponse()); } catch (Exception e) { //do something } ~~~ 而这时,我们只需要对相应的数据进行处理就可以了,如 ~~~ JSONArray jArray = new JSONArray(client.getResponse()); JSONObject jObj=jArray.getJSONObject(0); vshow.setText(jObj.toString()); outputJSON(jObj); ~~~ 将他转换为String,接着在Android端上显示最后的结果。
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