in the following code, i am trying to perform a GET operation on a webservice that i have coded and hosted on localhost. The method OpenHttpConnection is working just fine because i have put toasts in between to check if there was sth wrong in there. the app crashes when i try to convert the input stream into a string using the bufferreader. Please have a look and see if you can spot the error.<\/p>\n
Thanks \ud83d\ude42<\/p>\n
public class ServicetestActivity extends Activity {\n\n\n\npublic static String iStream_to_String(InputStream is1)\n{\n BufferedReader rd = new BufferedReader(new InputStreamReader(is1));\n String line;\n StringBuilder sb = new StringBuilder();\n try {\n while ((line = rd.readLine()) != null) {\n sb.append(line);\n }\n rd.close();\n\n } catch (IOException e) {\n \/\/ TODO Auto-generated catch block\n e.printStackTrace();\n }\n String contentOfMyInputStream = sb.toString();\n return contentOfMyInputStream;\n}\n\n\n\n\n\n\n\/** Called when the activity is first created. *\/\n@Override\npublic void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.main);\n InputStream is=null;\n try {\n is=OpenHttpConnection(\"http:\/\/localhost\/webservice.php?device=ayaz\");\n } catch (IOException e) {\n \/\/ TODO Auto-generated catch block\n e.printStackTrace();\n }\n String line= iStream_to_String(is);\n Toast.makeText(this, line, Toast.LENGTH_LONG).show(); \n}\n\n\n private InputStream OpenHttpConnection(String link) throws IOException {\n \/\/ TODO Auto-generated method stub\n InputStream inputStream = null;\n int response = -1;\n Toast.makeText(this, \"1\", Toast.LENGTH_SHORT).show();\n URL url = new URL(link);\n URLConnection connection = url.openConnection();\n Toast.makeText(this, \"2\", Toast.LENGTH_SHORT).show();\n if (!(connection instanceof HttpURLConnection))\n throw new IOException(\"Not a HTTP connection\");\n try {\n HttpURLConnection httpURLConnection = (HttpURLConnection) connection;\n Toast.makeText(this, \"3\", Toast.LENGTH_SHORT).show();\n httpURLConnection.setAllowUserInteraction(false);\n Toast.makeText(this, \"4\", Toast.LENGTH_SHORT).show();\n httpURLConnection.setInstanceFollowRedirects(true);\n httpURLConnection.setRequestMethod(\"GET\");\n httpURLConnection.connect();\n response = httpURLConnection.getResponseCode();\n if (response == HttpURLConnection.HTTP_OK) {\n inputStream = httpURLConnection.getInputStream();\n }\n\n } catch (Exception e) {\n \/\/ TODO: handle exception\n throw new IOException(\"Error connecting\");\n }\n return inputStream;}\n\n\/\/ see http:\/\/androidsnippets.com\/executing-a-http-get-request-with-httpclient\n<\/code><\/pre>\n}<\/p>\n
Also the log cat is as follows:<\/p>\n
10-14 20:54:13.660: E\/AndroidRuntime(1348): FATAL EXCEPTION: main\n10-14 20:54:13.660: E\/AndroidRuntime(1348): java.lang.RuntimeException: Unable to start activity ComponentInfo{web.service\/web.service.ServicetestActivity}: java.lang.NullPointerException\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread.access$1500(ActivityThread.java:117)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.os.Handler.dispatchMessage(Handler.java:99)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.os.Looper.loop(Looper.java:130)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread.main(ActivityThread.java:3683)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at java.lang.reflect.Method.invokeNative(Native Method)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at java.lang.reflect.Method.invoke(Method.java:507)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at dalvik.system.NativeStart.main(Native Method)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): Caused by: java.lang.NullPointerException\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at java.io.Reader.(Reader.java:65)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at java.io.InputStreamReader.(InputStreamReader.java:122)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at java.io.InputStreamReader.(InputStreamReader.java:59)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at web.service.ServicetestActivity.iStream_to_String(ServicetestActivity.java:31)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at web.service.ServicetestActivity.onCreate(ServicetestActivity.java:65)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)\n10-14 20:54:13.660: E\/AndroidRuntime(1348): ... 11 more\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"in the following code, i am trying to perform a GET operation on a webservice that i have coded and hosted on localhost. The method OpenHttpConnection is working just fine because i have put toasts in between to check if there was sth wrong in there. the app crashes when i try to convert the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5277","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/5277","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=5277"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/5277\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=5277"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=5277"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=5277"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}