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POAndroid app crashing on receiving intent bundle?
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2013-12-01T01:10:39.993
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I will preface this by saying I am a complete newb, this is my first project, and I have tried searching everywhere to answer my question. I have a login screen set up on android. Once the user hits the login button and the login name/password are correct, (validated in PHP/SQL) it sends an intent/bundle to the next activity. Here is the code to send the intent/bundle: <pre><code>Intent intent = new Intent(this, Homepage.class); EditText uname2 = (EditText)findViewById(R.id.txt_username); String username2 = uname2.getText().toString(); Intent intent2 = new Intent(this, Homepage.class); intent2.putExtra("username2", username2); startActivity(intent); </code></pre> Here is the code to receive the intent bundle on the next activity: <pre><code> Intent intent2 = getIntent(); String usernamefromlogin = intent2.getExtras().getString("username2"); String url5 = url.concat(usernamefromlogin); TextView text = (TextView) findViewById(R.id.errorchecking); text.setText(url5); </code></pre> I am using concat() to put a URL before the intent bundle because that URL is going to be used as a _GET command to a PHP file (but I digress). Currently, I have it set to place the text into a TextView so that I can see what the end result is, but the app crashes before I can get to that point. My app crashes when I hit the login button. Here is the Logcat I am getting: <pre><code>11-30 20:06:39.449: E/AndroidRuntime(4578): FATAL EXCEPTION: main 11-30 20:06:39.449: E/AndroidRuntime(4578): Process: com.sencide, PID: 4578 11-30 20:06:39.449: E/AndroidRuntime(4578): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sencide/com.sencide.Homepage}: java.lang.NullPointerException 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread.access$700(ActivityThread.java:135) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.os.Handler.dispatchMessage(Handler.java:102) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.os.Looper.loop(Looper.java:137) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread.main(ActivityThread.java:4998) 11-30 20:06:39.449: E/AndroidRuntime(4578): at java.lang.reflect.Method.invokeNative(Native Method) 11-30 20:06:39.449: E/AndroidRuntime(4578): at java.lang.reflect.Method.invoke(Method.java:515) 11-30 20:06:39.449: E/AndroidRuntime(4578): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777) 11-30 20:06:39.449: E/AndroidRuntime(4578): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593) 11-30 20:06:39.449: E/AndroidRuntime(4578): at dalvik.system.NativeStart.main(Native Method) 11-30 20:06:39.449: E/AndroidRuntime(4578): Caused by: java.lang.NullPointerException 11-30 20:06:39.449: E/AndroidRuntime(4578): at com.sencide.Homepage.onCreate(Homepage.java:46) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.Activity.performCreate(Activity.java:5243) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 11-30 20:06:39.449: E/AndroidRuntime(4578): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140) 11-30 20:06:39.449: E/AndroidRuntime(4578): ... 11 more 11-30 20:06:42.569: I/Process(4578): Sending signal. PID: 4578 SIG: 9 </code></pre> Here is my entire code: AndroidLogin.java <pre><code>public class AndroidLogin extends Activity implements OnClickListener { Button ok,back,exit; TextView result; String thisisausername; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Login button clicked ok = (Button)findViewById(R.id.btn_login); ok.setOnClickListener(this); result = (TextView)findViewById(R.id.tbl_result); } public void postLoginData() { // Create a new HttpClient and Post Header HttpClient httpclient = new DefaultHttpClient(); // login.php returns true if username and password match in db HttpPost httppost = new HttpPost("http://10.0.2.2/login.php"); try { // Add user name and password EditText uname = (EditText)findViewById(R.id.txt_username); String username = uname.getText().toString(); EditText pword = (EditText)findViewById(R.id.txt_password); String password = pword.getText().toString(); List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); nameValuePairs.add(new BasicNameValuePair("username", username)); nameValuePairs.add(new BasicNameValuePair("password", password)); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); // Execute HTTP Post Request Log.w("SENCIDE", "Execute HTTP Post Request"); HttpResponse response = httpclient.execute(httppost); String str = inputStreamToString(response.getEntity().getContent()).toString(); Log.w("SENCIDE", str); if(str.toString().equalsIgnoreCase("true")) { Log.w("SENCIDE", "TRUE"); result.setText("Login Successful! Please Wait..."); }else { Log.w("SENCIDE", "FALSE"); result.setText(str); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } private StringBuilder inputStreamToString(InputStream is) { String line = ""; StringBuilder total = new StringBuilder(); // Wrap a BufferedReader around the InputStream BufferedReader rd = new BufferedReader(new InputStreamReader(is)); // Read response until the end try { while ((line = rd.readLine()) != null) { total.append(line); } } catch (IOException e) { e.printStackTrace(); } // Return full string return total; } public void RegisterButton(View view) { String url = "http://10.0.2.2/register.php"; Intent i = new Intent(Intent.ACTION_VIEW); i.setData(Uri.parse(url)); startActivity(i); } @Override public void onClick(View view) { postLoginData(); // turns the text in the textview "Tbl_result" into a text string called "tblresult" TextView tblresult = (TextView) findViewById(R.id.tbl_result); // If "tblresult" text string matches the string "Login Successful! Please Wait..." exactly, it will switch to next activity if (tblresult.getText().toString().equals("Login Successful! Please Wait...")) { Intent intent = new Intent(this, Homepage.class); EditText uname2 = (EditText)findViewById(R.id.txt_username); String username2 = uname2.getText().toString(); intent.putExtra("username2", username2); startActivity(intent); } } } </code></pre> Homepage.Java <pre><code>public class Homepage extends Activity { //URL to get JSON Arrays public static String url = "http://x.x.x.x/SQL.php?username=123"; //JSON Node Names private static final String TAG_USER = "users"; private static final String TAG_ID = "uid"; private static final String TAG_NAME = "fullname"; private static final String TAG_DISPLAY = "displayname"; private static final String TAG_EMAIL = "email"; private static final String TAG_PW = "password"; private static final String TAG_CREATED = "created_at"; private static final String TAG_UPDATED = "updated_at"; JSONArray user = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Get login name from EditText in login screen and concatenate it to PHP user-name for _GET Intent intent2 = getIntent(); String usernamefromlogin = intent2.getExtras().getString("username2"); String url5 = url.concat(usernamefromlogin); TextView text = (TextView) findViewById(R.id.errorchecking); text.setText(url5); setContentView(R.layout.reshomepage); // Creating new JSON Parser JSONParser jParser = new JSONParser(); // Getting JSON from URL JSONObject json = jParser.getJSONFromUrl(url); try { // Getting JSON Array user = json.getJSONArray(TAG_USER); JSONObject c = user.getJSONObject(0); // Storing JSON item in a Variable String uid = c.getString(TAG_ID); String name = c.getString(TAG_NAME); String display = c.getString(TAG_DISPLAY); String email = c.getString(TAG_EMAIL); String pw = c.getString(TAG_PW); String created = c.getString(TAG_CREATED); String updated = c.getString(TAG_UPDATED); //Importing TextView final TextView uid1 = (TextView)findViewById(R.id.tvuid); final TextView name1 = (TextView)findViewById(R.id.tvfullname); final TextView display1 = (TextView)findViewById(R.id.tvdisplayname); final TextView email1 = (TextView)findViewById(R.id.tvemail); final TextView pw1 = (TextView)findViewById(R.id.tvpassword); final TextView created1 = (TextView)findViewById(R.id.tvcreated_at); final TextView updated1 = (TextView)findViewById(R.id.tvupdated_at); //Set JSON Data in TextView uid1.setText(uid); name1.setText(name); display1.setText(display); email1.setText(email); pw1.setText(pw); created1.setText(created); updated1.setText(updated); } catch (JSONException e) { e.printStackTrace(); } } } </code></pre> JSONParser.java <pre><code>public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } public JSONObject getJSONFromUrl(String url) { // Making HTTP request try { // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } </code></pre> Main.XML (first login screen) <pre><code><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" >  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/lbl_top" android:textSize="16sp" android:typeface="sans" android:text="Please Login" />  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/lbl_username" android:text="User Name (e-mail)" />  <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:textSize="18sp" android:id="@+id/txt_username" />  <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/lbl_password" android:text="Password" />  <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:password="true" android:id="@+id/txt_password" />  <Button android:layout_width="match_parent" android:layout_height="35dp" android:id="@+id/btn_login" android:text="Login" android:onClick="LoginScreenButton" />  <Button android:layout_width="match_parent" android:layout_height="35dp" android:id="@+id/register" android:text="New Registration" android:onClick="RegisterButton" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tbl_result" android:textColor="#00FF00" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tbl_result2" android:textColor="#00FF00" /> </LinearLayout> </code></pre> reshomepage.XML (second screen where I am trying to send intent to) <pre><code><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="vertical" > <TextView android:id="@+id/tvuid" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvfullname" android:layout_width="match_parent" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvdisplayname" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvemail" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvpassword" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvcreated_at" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/tvupdated_at" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <TextView android:id="@+id/errorchecking" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout> </code></pre>
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Android app crashing on receiving intent bundle?
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