List shows as not null but ArrayAdapter throws NullPointerException

List shows as not null but ArrayAdapter throws NullPointerException - java

Can anyone please help me? I just don't understand why does it throw null pointer exception.
I work with ksoap2,WCF web methods and android. I checked the "list" in debugger mode and it is not null.
Here is my code:
public class MainActivity extends Activity {
String loginMemberId = "a001";
Context context;
List list;
ListView listView;
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
getBeneficiariesNameSet BNL = new getBeneficiariesNameSet();
try {
list = BNL.execute().get();
if(list!=null && list.size()>0) {
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, list); //null pointer exception,line 43
listView = (ListView) findViewById(R.id.listBeneficiaries);
listView.setAdapter(arrayAdapter);
}else{
Toast.makeText(context,"No data in array",Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public class getBeneficiariesNameSet extends AsyncTask<String, Void, List<String>> {
private final ProgressDialog dialog = new ProgressDialog(MainActivity.this);
#Override
protected List<String> doInBackground(String... params) {
TestArray CS = new TestArray();
List<String> response = CS.getBeneficiariesNameSet(loginMemberId);
return response;
}
#Override
protected void onPostExecute(List<String> s) {
super.onPostExecute(s);
dialog.dismiss();
}
}
}
And here is the Log cat.
06-11 14:22:20.484 22245-22245/? W/System.err﹕ java.lang.NullPointerException
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.widget.ArrayAdapter.init(ArrayAdapter.java:310)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:153)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at com.example.administrator.androidwcf.MainActivity$1.onClick(MainActivity.java:43)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.view.View.performClick(View.java:4443)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.view.View$PerformClick.run(View.java:18442)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:733)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.os.Looper.loop(Looper.java:136)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5021)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:515)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643)
06-11 14:22:20.484 22245-22245/? W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)
06-11 14:22:20.514 599-624/? W/audio_hw_primary﹕ out_write() limiting sleep time 112539 to 46439
06-11 14:22:20.584 599-624/? W/audio_hw_primary﹕ out_write() limiting sleep time 65759 to 46439

Your context is null. Use MainActivity.this for a context in an anon inner class of your activity.

Related

NumberFormatException invalid int ""

I am trying to take the input values from EditText and I want to save it to sqlite Database. I dont know how to use the logcat [also please explain how can I read the errors from the LogCat].
MainActivity.java:
package com.example.database;
import android.support.v7.app.ActionBarActivity;
import android.text.Editable;
import android.app.Activity;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity{
EditText first,last,age,classc;
Button add,view;
String FirstName;
String LastName,Class;
Integer Age;
sqLit myDB;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myDB = new sqLit(this);
Link();
xmlToVar();
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Integer flag=myDB.insertValue(FirstName, LastName, Class, Age);
if (flag==1)
{
Context context=getApplicationContext();
Toast toast = Toast.makeText(context, "Record Added" , Toast.LENGTH_LONG);
toast.show();
}
else
{
Context context=getApplicationContext();
Toast toast = Toast.makeText(context, "Error Occured" , Toast.LENGTH_LONG);
toast.show();
}
}
});
}
public void Link()
{
first=(EditText) findViewById(R.id.editFirst);
last=(EditText) findViewById(R.id.editLast);
classc=(EditText) findViewById(R.id.editClass);
age=(EditText) findViewById(R.id.editAge);
add=(Button) findViewById(R.id.Add);
view=(Button) findViewById(R.id.ViewAll);
}
public void xmlToVar()
{
FirstName = first.getText().toString();
LastName = last.getText().toString();
Class = classc.getText().toString();
Age = Integer.parseInt(age.getText().toString());
}
}
sqLit.java:
package com.example.database;
import org.w3c.dom.Text;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
public class sqLit extends SQLiteOpenHelper
{
public static final String DB_NAME="student12.db";
public static final String TABLE_NAME="class1";
public static final String COL_1="ROLL NO";
public static final String COL_2="First Name";
public static final String COL_3="Last Name";
public static final String COL_4="Class";
public static final String COL_5="Age";
public sqLit(Context context) {
super(context, DB_NAME, null, 1);
// TODO Auto-generated constructor stub
}
#Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("Create table " + TABLE_NAME + "(" + COL_1 + "INTEGER AUTOINCREMENT PRIMARY KEY," + COL_2 + "TEXT," + COL_3 + "TEXT," + COL_4 + "TEXT," + COL_5 + "INTEGER)");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("Drop Table If Exist" + TABLE_NAME );
onCreate(db);
}
public Integer insertValue(String FirstName, String LastName, String Class, Integer Age)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentV = new ContentValues();
contentV.put(COL_2, FirstName);
contentV.put(COL_3, LastName);
contentV.put(COL_4, Class);
contentV.put(COL_5, Age);
long isInserted = db.insert(TABLE_NAME, null, contentV);
if (isInserted == -1){
return 0;
}
else
{
return 1;
}
}
}
Also, please explain how to use LogCat as I don't understand how to read it.
LOGCAT:
06-11 18:44:39.650: E/Trace(29536): error opening trace file: No such file or directory (2)
06-11 18:44:39.660: D/AndroidRuntime(29536): Shutting down VM
06-11 18:44:39.660: W/dalvikvm(29536): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
06-11 18:44:39.660: E/AndroidRuntime(29536): FATAL EXCEPTION: main
06-11 18:44:39.660: E/AndroidRuntime(29536): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread.access$600(ActivityThread.java:130)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.os.Handler.dispatchMessage(Handler.java:99)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.os.Looper.loop(Looper.java:137)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-11 18:44:39.660: E/AndroidRuntime(29536): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 18:44:39.660: E/AndroidRuntime(29536): at java.lang.reflect.Method.invoke(Method.java:511)
06-11 18:44:39.660: E/AndroidRuntime(29536): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-11 18:44:39.660: E/AndroidRuntime(29536): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-11 18:44:39.660: E/AndroidRuntime(29536): at dalvik.system.NativeStart.main(Native Method)
06-11 18:44:39.660: E/AndroidRuntime(29536): Caused by: java.lang.NumberFormatException: Invalid int: ""
06-11 18:44:39.660: E/AndroidRuntime(29536): at java.lang.Integer.invalidInt(Integer.java:138)
06-11 18:44:39.660: E/AndroidRuntime(29536): at java.lang.Integer.parseInt(Integer.java:359)
06-11 18:44:39.660: E/AndroidRuntime(29536): at java.lang.Integer.parseInt(Integer.java:332)
06-11 18:44:39.660: E/AndroidRuntime(29536): at com.example.database.MainActivity.xmlToVar(MainActivity.java:72)
06-11 18:44:39.660: E/AndroidRuntime(29536): at com.example.database.MainActivity.onCreate(MainActivity.java:34)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.Activity.performCreate(Activity.java:5008)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
06-11 18:44:39.660: E/AndroidRuntime(29536): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
06-11 18:44:39.660: E/AndroidRuntime(29536): ... 11 more
06-11 18:46:03.652: D/dalvikvm(30256): Not late-enabling CheckJNI (already on)
06-11 18:46:03.682: E/Trace(30256): error opening trace file: No such file or directory (2)
06-11 18:46:03.712: D/AndroidRuntime(30256): Shutting down VM
06-11 18:46:03.712: W/dalvikvm(30256): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
06-11 18:46:03.712: E/AndroidRuntime(30256): FATAL EXCEPTION: main
06-11 18:46:03.712: E/AndroidRuntime(30256): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread.access$600(ActivityThread.java:130)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.os.Handler.dispatchMessage(Handler.java:99)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.os.Looper.loop(Looper.java:137)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-11 18:46:03.712: E/AndroidRuntime(30256): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 18:46:03.712: E/AndroidRuntime(30256): at java.lang.reflect.Method.invoke(Method.java:511)
06-11 18:46:03.712: E/AndroidRuntime(30256): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-11 18:46:03.712: E/AndroidRuntime(30256): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-11 18:46:03.712: E/AndroidRuntime(30256): at dalvik.system.NativeStart.main(Native Method)
06-11 18:46:03.712: E/AndroidRuntime(30256): Caused by: java.lang.NumberFormatException: Invalid int: ""
06-11 18:46:03.712: E/AndroidRuntime(30256): at java.lang.Integer.invalidInt(Integer.java:138)
06-11 18:46:03.712: E/AndroidRuntime(30256): at java.lang.Integer.parseInt(Integer.java:359)
06-11 18:46:03.712: E/AndroidRuntime(30256): at java.lang.Integer.parseInt(Integer.java:332)
06-11 18:46:03.712: E/AndroidRuntime(30256): at com.example.database.MainActivity.xmlToVar(MainActivity.java:73)
06-11 18:46:03.712: E/AndroidRuntime(30256): at com.example.database.MainActivity.onCreate(MainActivity.java:35)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.Activity.performCreate(Activity.java:5008)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
06-11 18:46:03.712: E/AndroidRuntime(30256): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
06-11 18:46:03.712: E/AndroidRuntime(30256): ... 11 more
06-11 18:53:33.378: E/Trace(2383): error opening trace file: No such file or directory (2)
06-11 18:53:33.408: D/AndroidRuntime(2383): Shutting down VM
06-11 18:53:33.408: W/dalvikvm(2383): threadid=1: thread exiting with uncaught exception (group=0xb3f2b288)
06-11 18:53:33.408: E/AndroidRuntime(2383): FATAL EXCEPTION: main
06-11 18:53:33.408: E/AndroidRuntime(2383): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database/com.example.database.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread.access$600(ActivityThread.java:130)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.os.Handler.dispatchMessage(Handler.java:99)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.os.Looper.loop(Looper.java:137)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread.main(ActivityThread.java:4745)
06-11 18:53:33.408: E/AndroidRuntime(2383): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 18:53:33.408: E/AndroidRuntime(2383): at java.lang.reflect.Method.invoke(Method.java:511)
06-11 18:53:33.408: E/AndroidRuntime(2383): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
06-11 18:53:33.408: E/AndroidRuntime(2383): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-11 18:53:33.408: E/AndroidRuntime(2383): at dalvik.system.NativeStart.main(Native Method)
06-11 18:53:33.408: E/AndroidRuntime(2383): Caused by: java.lang.NumberFormatException: Invalid int: ""
06-11 18:53:33.408: E/AndroidRuntime(2383): at java.lang.Integer.invalidInt(Integer.java:138)
06-11 18:53:33.408: E/AndroidRuntime(2383): at java.lang.Integer.parseInt(Integer.java:359)
06-11 18:53:33.408: E/AndroidRuntime(2383): at java.lang.Integer.parseInt(Integer.java:332)
06-11 18:53:33.408: E/AndroidRuntime(2383): at com.example.database.MainActivity.xmlToVar(MainActivity.java:73)
06-11 18:53:33.408: E/AndroidRuntime(2383): at com.example.database.MainActivity.onCreate(MainActivity.java:35)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.Activity.performCreate(Activity.java:5008)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
06-11 18:53:33.408: E/AndroidRuntime(2383): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
06-11 18:53:33.408: E/AndroidRuntime(2383): ... 11 more

Caused by: java.lang.NumberFormatException: Invalid int: ""
(after FATAL EXCEPTION:) tells us you are trying to parse an int but the value you are trying to parse is an empty String.
this line (the first that references your class) tells us which line it was
at com.example.database.MainActivity.xmlToVar(MainActivity.java:72)
this is happening because you are calling it in onCreate() before the EditText has any value entered.
From the line above, we can see that the error happens in MainActivity in the method xmlToVar at line 72 which should be
Age = Integer.parseInt(age.getText().toString());
To solve this, you should call that method in an onClick or some event listener. You also should surround it in a try/catch or use some other validation checking.
You should read the following questions and their answers for more details:
What is a stack trace, and how can I use it to debug my application errors?
Unfortunately MyApp has stopped. How can I solve this?
java.lang.NumberFormatException: Invalid int: "" in android
basically, read the error it gives you then look for the first line which mentions your class. Sometimes you need to read deeper but for basic errors that is usually enough.
Also Please Explain how to use LogCat as I am 3 days Old Android Programmer. I never used Eclipse.
Note that the stacktrace isn't Eclipse or even Java/Android specific. You can get some sort of crash log like this in other languages/IDEs/Consoles

The problem is here:
Age = Integer.parseInt(age.getText().toString());
age.getText().toString() equals "" and which causes the NumberFormatException

java.lang.runtimeexception unable to start activity componentinfo java.lang.nullpointerexception android

im making a simple calories calculator and it gives me that error, i already reviewed the code and searched here for the solution but im not able to see why is not running.
I thought it was because i had not initialized the variable, so i did it and still got the same error, maybe is something with the spinners, im new on using spinners
here is the code:
public class CaloriesCalculator extends ActionBarActivity {
EditText etAge, etWeight, etHeight;
Button btnCalculate;
TextView tvResult;
Spinner spinnerGender, spinnerActivity;
String itemGender, itemActivity;
int Height=0;
int Weight=0;
int Age=0;;
double bmr=0.0;
double tdee=0.0;
String result;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.caloriescalculator);
spinnerGender=(Spinner)findViewById(R.id.spinnerGender);
spinnerActivity=(Spinner)findViewById(R.id.spinnerActivity);
etAge=(EditText)findViewById(R.id.etAge);
etWeight=(EditText)findViewById(R.id.etWeight);
etHeight=(EditText)findViewById(R.id.etHeight);
tvResult=(TextView)findViewById(R.id.tvResult);
List<String> list = new ArrayList<String>();
list.add("Male");
list.add("Female");
ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_dropdown_item, list );
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerGender.setAdapter(dataAdapter);
List<String> list2 = new ArrayList<String>();
list.add("Sedentary");
list.add("Lightly Active");
list.add("Moderalety Active");
list.add("Very Active");
list.add("Extremely Active");
ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_dropdown_item, list2 );
dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinnerActivity.setAdapter(dataAdapter2);
btnCalculate.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
spinnerGender.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent,
View view, int position, long id) {
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});
spinnerActivity.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent,
View view, int position, long id) {
// TODO Auto-generated method stub
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});
itemGender=String.valueOf(spinnerGender.getSelectedItem());
itemActivity=String.valueOf(spinnerActivity.getSelectedItem());
if(itemGender=="Male"){
Weight=Integer.parseInt(etWeight.getText().toString());
Height=Integer.parseInt(etHeight.getText().toString());
Age=Integer.parseInt(etAge.getText().toString());
if(itemActivity=="Sedentary"){
bmr=66+((13.7 * Weight)+(5*Height))-(6.8*Age);
tdee=bmr*1.2;
}
else if(itemActivity=="Lightly Active"){
bmr=66+((13.7 * Weight)+(5*Height))-(6.8*Age);
tdee=bmr*1.375;
}
else if(itemActivity=="Moderalety Active"){
bmr=66+((13.7 * Weight)+(5*Height))-(6.8*Age);
tdee=bmr*1.55;
}
else if(itemActivity=="Very Active"){
bmr=66+((13.7 * Weight)+(5*Height))-(6.8*Age);
tdee=bmr*1.725;
}
else if(itemActivity=="Extremely Active"){
bmr=66+((13.7 * Weight)+(5*Height))-(6.8*Age);
tdee=bmr*1.9;
}
}
else if(itemGender=="Female") {
Weight=Integer.parseInt(etWeight.getText().toString());
Height=Integer.parseInt(etHeight.getText().toString());
Age=Integer.parseInt(etAge.getText().toString());
if(itemActivity=="Sedentary"){
bmr=655+((9.6*Weight)+(1.8*Height))-(4.7*Age);
tdee=bmr*1.2;
}
else if(itemActivity=="Lightly Active"){
bmr=655+((9.6*Weight)+(1.8*Height))-(4.7*Age);
tdee=bmr*1.375;
}
else if(itemActivity=="Moderalety Active"){
bmr=655+((9.6*Weight)+(1.8*Height))-(4.7*Age);
tdee=bmr*1.55;
}
else if(itemActivity=="Very Active"){
bmr=655+((9.6*Weight)+(1.8*Height))-(4.7*Age);
tdee=bmr*1.725;
}
else if(itemActivity=="Extremely Active"){
bmr=655+((9.6*Weight)+(1.8*Height))-(4.7*Age);
tdee=bmr*1.9;
}
}
result=Double.toString(tdee);
tvResult.setText(result);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
logcat:
11-28 17:20:05.501: E/AndroidRuntime(1455): FATAL EXCEPTION: main
11-28 17:20:05.501: E/AndroidRuntime(1455): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.calculadoracalorias/com.app.calculadoracalorias.CaloriesCalculator}: java.lang.NullPointerException
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.os.Handler.dispatchMessage(Handler.java:99)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.os.Looper.loop(Looper.java:137)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread.main(ActivityThread.java:5103)
11-28 17:20:05.501: E/AndroidRuntime(1455): at java.lang.reflect.Method.invokeNative(Native Method)
11-28 17:20:05.501: E/AndroidRuntime(1455): at java.lang.reflect.Method.invoke(Method.java:525)
11-28 17:20:05.501: E/AndroidRuntime(1455): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-28 17:20:05.501: E/AndroidRuntime(1455): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-28 17:20:05.501: E/AndroidRuntime(1455): at dalvik.system.NativeStart.main(Native Method)
11-28 17:20:05.501: E/AndroidRuntime(1455): Caused by: java.lang.NullPointerException
11-28 17:20:05.501: E/AndroidRuntime(1455): at com.app.calculadoracalorias.CaloriesCalculator.onCreate(CaloriesCalculator.java:67)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.Activity.performCreate(Activity.java:5133)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-28 17:20:05.501: E/AndroidRuntime(1455): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
11-28 17:20:05.501: E/AndroidRuntime(1455): ... 11 more
11-28 17:24:42.341: D/AndroidRuntime(1507): Shutting down VM
11-28 17:24:42.341: W/dalvikvm(1507): threadid=1: thread exiting with uncaught exception (group=0x41465700)
11-28 17:24:42.371: E/AndroidRuntime(1507): FATAL EXCEPTION: main
11-28 17:24:42.371: E/AndroidRuntime(1507): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app.calculadoracalorias/com.app.calculadoracalorias.CaloriesCalculator}: java.lang.NullPointerException
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.os.Handler.dispatchMessage(Handler.java:99)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.os.Looper.loop(Looper.java:137)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread.main(ActivityThread.java:5103)
11-28 17:24:42.371: E/AndroidRuntime(1507): at java.lang.reflect.Method.invokeNative(Native Method)
11-28 17:24:42.371: E/AndroidRuntime(1507): at java.lang.reflect.Method.invoke(Method.java:525)
11-28 17:24:42.371: E/AndroidRuntime(1507): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-28 17:24:42.371: E/AndroidRuntime(1507): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-28 17:24:42.371: E/AndroidRuntime(1507): at dalvik.system.NativeStart.main(Native Method)
11-28 17:24:42.371: E/AndroidRuntime(1507): Caused by: java.lang.NullPointerException
11-28 17:24:42.371: E/AndroidRuntime(1507): at com.app.calculadoracalorias.CaloriesCalculator.onCreate(CaloriesCalculator.java:70)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.Activity.performCreate(Activity.java:5133)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-28 17:24:42.371: E/AndroidRuntime(1507): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
11-28 17:24:42.371: E/AndroidRuntime(1507): ... 11 more

Yout btnCalculate is null, you should initialize before doing the onclickListener:
btnCalculate = (Button)findViewById(R.id.btnCalculate); //your id
Also note that you are initializing the dataAdapter2 but actually you are using dataAdapert, and list2 dont have any elements, because you declare it but u are filling always list1

How to write to a TextView from outside a button or onCreate

OK,time for another noobie question:
I have declared a TextView at the top of the Activity class as static which I believe should make it "global". Then in onCreate I attach that variable to a TextView. Looks like so:
public class CheckerActivity extends Activity {
String testNumber = "0";
public static TextView displayArray;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_checker);
int[] numbersArray;
Intent intent = getIntent();
numbersArray = intent.getIntArrayExtra(EnterCurrentNumbersActivity.CURRENT_NUMBERS_ARRAY);
String arrayStringed = Arrays.toString(numbersArray);
displayArray = (TextView) findViewById(R.id.currentNumbers);
displayArray.setText(arrayStringed);
}
Then in a method I created myself in the same class I'm trying to use that TextView declaration and write something to it. Like so:
public void addNumber(String[] numbersToAdd) {
this.setContentView(R.layout.activity_checker);
displayArray.setText(Arrays.toString(numbersToAdd));
}
I then have a button that calls the addNumber method like so:
public void populateButton(View view) {
String[] temp = {"test", "array"};
CheckerActivity addNumbers = new CheckerActivity();
addNumbers.addNumber(temp);
}
But when the button is clicked I keep getting NullPointerException on the addNumber method.
I've searched all over for this but I think I just don't know what to ask Google. As far as I can tell, this should work, where am I going wrong??
logcat after your sugestions. (But Eldar Mensutov got it. Works now!)
07-09 15:49:48.542 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ java.lang.NullPointerException
07-09 15:49:48.542 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at au.com.acent.ash.basiclottochecker.CheckerActivity.addNumber(CheckerActivity.java:85)
07-09 15:49:48.542 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at au.com.acent.ash.basiclottochecker.CheckerActivity.populateButton(CheckerActivity.java:37)
07-09 15:49:48.542 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:525)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.view.View$1.onClick(View.java:3809)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.view.View.performClick(View.java:4421)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.view.View$PerformClick.run(View.java:17903)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:730)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:92)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.os.Looper.loop(Looper.java:213)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5225)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:525)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
07-09 15:49:48.552 21036-21036/au.com.acent.ash.basiclottochecker W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)
To carry of from this question, I now wish to call
public void addNumber(String[] numbersToAdd)
from a completely different class (whole different file within the same project)
Using this.addNumber(temp); doesn't work.
Any suggestions??

Do not call
this.setContentView(R.layout.activity_checker);
in your public void addNumber(String[] numbersToAdd).
And replase
CheckerActivity addNumbers = new CheckerActivity();
addNumbers.addNumber(temp);
on
this.addNumber(temp);
And make you field not static: public TextView displayArray;

My Android Application to show text on Click Stop Working

I have a very very simple project in which what I am trying to achieve is to that when a user click on the button it display the text. But in the ADB it says unfortunately showtext stop working. What is the reason behind this?
I had tried but not got any result. My code is fine but not working. Below is java code for it. I omitted xml code as it contain only the button and a text view not so complex.
public class MainActivity extends Activity {
Button ShowText;
TextView DisplayText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ShowText=(Button)findViewById(R.id.bShowText);
}
void ShowMeText(View view){
DisplayText=(TextView)findViewById(R.id.tvShowText);
DisplayText.setVisibility(View.VISIBLE);
}
}
Try solve my this little issue. Thanks in Advance.
As someone asked for logcat error here is it -
06-11 06:51:32.376: E/AndroidRuntime(1223): FATAL EXCEPTION: main
06-11 06:51:32.376: E/AndroidRuntime(1223): java.lang.IllegalStateException: Could not find a method ShowMeText(View) in the activity class com.mylearning.showtext.MainActivity for onClick handler on view class android.widget.Button with id 'bShowText'
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.view.View$1.onClick(View.java:3620)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.view.View.performClick(View.java:4240)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.view.View$PerformClick.run(View.java:17721)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.os.Handler.handleCallback(Handler.java:730)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.os.Handler.dispatchMessage(Handler.java:92)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.os.Looper.loop(Looper.java:137)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.app.ActivityThread.main(ActivityThread.java:5103)
06-11 06:51:32.376: E/AndroidRuntime(1223): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 06:51:32.376: E/AndroidRuntime(1223): at java.lang.reflect.Method.invoke(Method.java:525)
06-11 06:51:32.376: E/AndroidRuntime(1223): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
06-11 06:51:32.376: E/AndroidRuntime(1223): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
06-11 06:51:32.376: E/AndroidRuntime(1223): at dalvik.system.NativeStart.main(Native Method)
06-11 06:51:32.376: E/AndroidRuntime(1223): Caused by: java.lang.NoSuchMethodException: ShowMeText [class android.view.View]
06-11 06:51:32.376: E/AndroidRuntime(1223): at java.lang.Class.getConstructorOrMethod(Class.java:423)
06-11 06:51:32.376: E/AndroidRuntime(1223): at java.lang.Class.getMethod(Class.java:787)
06-11 06:51:32.376: E/AndroidRuntime(1223): at android.view.View$1.onClick(View.java:3613)
06-11 06:51:32.376: E/AndroidRuntime(1223): ... 11 more

You need to add android:onClick="ShowMeText" in your Button in your Layout. like so
<Button .............
android:onClick="ShowMeText"
......... />
and used lower case for method creation as Java naming Convention . like so showmetext
and also defined your ShowMeText(...) method as Public

ShowMeText(View v) has to be public.
Btw. start function names with lower case characters as specified by Java code style.

<Button
android:id="#+id/tvShowText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="ShowMeText" />
in java code
public void ShowMeText(View v){
DisplayText=(TextView)findViewById(R.id.tvShowText);
DisplayText.setVisibility(View.VISIBLE);
}

public class MainActivity extends Activity implements OnClickListener {
Button ShowText;
TextView DisplayText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ShowText = (Button) findViewById(R.id.bShowText);
DisplayText = (TextView) findViewById(R.id.tvShowText);
ShowText.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if (v.getId() == ShowText.getId())
// need to check ID because from which view has fire event soo we can handle appropriate
DisplayText.setVisibility(View.VISIBLE);
}
}

// Try this way,hope this will help you to solve your problem.
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center">
<Button
android:id="#+id/bShowText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ShowText"
android:onClick="ShowMeText"/>
<TextView
android:id="#+id/tvShowText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:visibility="gone"
android:text="TextView With Some Text"/>
</LinearLayout>
MainActivity.java
public class MainActivity extends Activity {
private TextView tvShowText;
private Button bShowText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvShowText = (TextView)findViewById(R.id.tvShowText);
bShowText = (Button)findViewById(R.id.bShowText);
}
public void ShowMeText(View v){
if(v.getId() == bShowText.getId()) {
if(tvShowText.getVisibility() == View.VISIBLE){
tvShowText.setVisibility(View.GONE);
}else{
tvShowText.setVisibility(View.VISIBLE);
}
}
}
}

Try this:
public class MainActivity extends Activity {
Button ShowText;
TextView DisplayText;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ShowText=(Button)findViewById(R.id.bShowText);
DisplayText=(TextView)findViewById(R.id.tvShowText);
DisplayText.setVisibility(View.Gone);
ShowText.setonClickListener(this);
}
public void ShowMeText(View view){
DisplayText.setVisibility(View.VISIBLE);
DisplayText.setText("Show your Text");
}
}

Android App crashes right on start

I have an app that's supposed to get some string from a server depending on the webpage, and it crashes every time I run it. I don't understand how to even debug it, and I've tried numerous changes. It started crashing ever since I messed with the GUI, and added the ability to switch views if that provides any sort of help.
Here is the code:
public class MainActivity extends Activity implements TextToSpeech.OnInitListener, OnClickListener{
private WebView mWebview;
EditText addressBar;
String currentWebpage = "http://www.aljazeera.com/news/americas/2013/07/20137113200544375.html";
LinearLayout viewGroup = (LinearLayout) findViewById(R.id.linearview);
View main = (View) findViewById(R.layout.activity_main);
View readOut = (View) findViewById(R.layout.read_out);
#Override
public void onCreate(Bundle savedInstanceState) {
System.out.println("Showing Activity_Main...");
viewGroup.addView(View.inflate(this, R.layout.activity_main, null));
super.onCreate(savedInstanceState);
//setContentView(R.menu.main);
addressBar = (EditText)findViewById(R.id.addressBar);
addressBar.setText(currentWebpage);
mWebview = (WebView)findViewById(R.id.webview);
mWebview.getSettings().setJavaScriptEnabled(true); // enables javascript
mWebview.setWebViewClient(new WebViewClient());
System.out.println("Loading Webpage...");
mWebview.loadUrl(currentWebpage);
}
public void speakOut(String text) {
TextToSpeech tts = new TextToSpeech(this, this);
System.out.println("Speaking");
if(tts.isLanguageAvailable(Locale.ENGLISH) != -1){
tts.speak(text, TextToSpeech.QUEUE_FLUSH, null);
}
}
public int speakFull(String text){
switchToRead();
String[] sentences = text.split("\n|\\.(?!\\d)|(?<!\\d)\\."); // Regex that splits the body of text into the sentences of that body which are stored in a String array.
for(int i = 0; i < sentences.length; i++){
speakOut(sentences[i]);
if(i == sentences.length - 1){
return 1;
}
}
return 0;
}
public String getText(String webPage) throws ParseException, IOException{
HttpResponse response = null;
try {
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI("http://someserver.net:8080/" + webPage));
response = client.execute(request);
} catch (URISyntaxException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
String responseBody = "No text found on webpage.";
int responseCode = response.getStatusLine().getStatusCode();
switch(responseCode) {
case 200:
HttpEntity entity = response.getEntity();
if(entity != null) {
responseBody = EntityUtils.toString(entity);
}
}
System.out.println("Returning Response..");
System.out.println(responseBody);
return responseBody;
}
#Override
public void onInit(int status) {
// TODO Auto-generated method stub
}
private class tts extends AsyncTask<String, Void, String>{//Async http request to get text
#Override
protected String doInBackground(String... arg0) {
try {
System.out.println("Running seperate thread for TTS.");
int complete = 0;
while(complete == 0){
System.out.println("Speaking full..");
complete = speakFull(getText(mWebview.getUrl()));
}
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String result){
}
}
public void clickPlay(View v){
new tts().execute("");
}
public void clickGo(View v){
if(addressBar.getText() != null){
currentWebpage = addressBar.getText().toString();
System.out.println("Current webpage changed to: " + currentWebpage);
mWebview.loadUrl(currentWebpage);
}
}
public void clickPause(View v){
System.out.println("Clicked pause.");
}
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
public void switchToRead(){// Switches to the reading view which displays the text that the tts engine reads off.
System.out.println("Swtiching view to Read.");
viewGroup.removeView(main);
viewGroup.addView(View.inflate(this, R.layout.read_out, null));
}
public void switchToMain(){
System.out.println("Switching view to Main.");
viewGroup.removeView(readOut);
viewGroup.addView(View.inflate(this, R.layout.activity_main, null));
}
}
Also here are the numerous errors I encounter when launching my app:
08-01 14:53:10.210: E/Trace(812): error opening trace file: No such file or directory (2)
08-01 14:53:10.600: D/AndroidRuntime(812): Shutting down VM
08-01 14:53:10.631: W/dalvikvm(812): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
08-01 14:53:10.660: E/AndroidRuntime(812): FATAL EXCEPTION: main
08-01 14:53:10.660: E/AndroidRuntime(812): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.webview/com.example.webview.MainActivity}: java.lang.NullPointerException
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.os.Handler.dispatchMessage(Handler.java:99)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.os.Looper.loop(Looper.java:137)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread.main(ActivityThread.java:5041)
08-01 14:53:10.660: E/AndroidRuntime(812): at java.lang.reflect.Method.invokeNative(Native Method)
08-01 14:53:10.660: E/AndroidRuntime(812): at java.lang.reflect.Method.invoke(Method.java:511)
08-01 14:53:10.660: E/AndroidRuntime(812): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-01 14:53:10.660: E/AndroidRuntime(812): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-01 14:53:10.660: E/AndroidRuntime(812): at dalvik.system.NativeStart.main(Native Method)
08-01 14:53:10.660: E/AndroidRuntime(812): Caused by: java.lang.NullPointerException
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.Activity.findViewById(Activity.java:1839)
08-01 14:53:10.660: E/AndroidRuntime(812): at com.example.webview.MainActivity.<init>(MainActivity.java:39)
08-01 14:53:10.660: E/AndroidRuntime(812): at java.lang.Class.newInstanceImpl(Native Method)
08-01 14:53:10.660: E/AndroidRuntime(812): at java.lang.Class.newInstance(Class.java:1319)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
08-01 14:53:10.660: E/AndroidRuntime(812): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
08-01 14:53:10.660: E/AndroidRuntime(812): ... 11 more
08-01 14:53:27.439: D/AndroidRuntime(860): Shutting down VM
08-01 14:53:27.439: W/dalvikvm(860): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
08-01 14:53:27.449: E/AndroidRuntime(860): FATAL EXCEPTION: main
08-01 14:53:27.449: E/AndroidRuntime(860): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.webview/com.example.webview.MainActivity}: java.lang.NullPointerException
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.os.Handler.dispatchMessage(Handler.java:99)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.os.Looper.loop(Looper.java:137)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread.main(ActivityThread.java:5041)
08-01 14:53:27.449: E/AndroidRuntime(860): at java.lang.reflect.Method.invokeNative(Native Method)
08-01 14:53:27.449: E/AndroidRuntime(860): at java.lang.reflect.Method.invoke(Method.java:511)
08-01 14:53:27.449: E/AndroidRuntime(860): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-01 14:53:27.449: E/AndroidRuntime(860): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-01 14:53:27.449: E/AndroidRuntime(860): at dalvik.system.NativeStart.main(Native Method)
08-01 14:53:27.449: E/AndroidRuntime(860): Caused by: java.lang.NullPointerException
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.Activity.findViewById(Activity.java:1839)
08-01 14:53:27.449: E/AndroidRuntime(860): at com.example.webview.MainActivity.<init>(MainActivity.java:39)
08-01 14:53:27.449: E/AndroidRuntime(860): at java.lang.Class.newInstanceImpl(Native Method)
08-01 14:53:27.449: E/AndroidRuntime(860): at java.lang.Class.newInstance(Class.java:1319)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
08-01 14:53:27.449: E/AndroidRuntime(860): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
08-01 14:53:27.449: E/AndroidRuntime(860): ... 11 more

Move your view initialization inside onCreate after setContentView
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mylayout);
LinearLayout viewGroup = (LinearLayout) findViewById(R.id.linearview);
...// rest of the code

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Java is a programming language and computing platform first released by Sun Microsystems in 1995.

List shows as not null but ArrayAdapter throws NullPointerException - java

Your context is null. Use MainActivity.this for a context in an anon inner class of your activity.

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