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AndroidStudio- Fatal error: IndexOutOfBoundsException: Invalid index 0, size is 0

I was able to run my app successfully through the emulator. but suddenly a bunch of errors appeared so now I am not able to launch it. There is a Fatal error. Here is LogCat output:
08-26 12:14:27.937 2112-2112/com.joudi.myapplication D/AndroidRuntime﹕ Shutting down VM
08-26 12:14:27.938 2112-2112/com.joudi.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.joudi.myapplication, PID: 2112
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.joudi.myapplication/com.joudi.myapplication.MainActivity}: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at com.joudi.myapplication.MainActivity.onCreate(MainActivity.java:29)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
            at android.app.ActivityThread.-wrap11(ActivityThread.java)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:148)
            at android.app.ActivityThread.main(ActivityThread.java:5417)
            at java.lang.reflect.Method.invoke(Native Method)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
I do not know ow to fix the "IndexOutOfBoundsException: Invalid index 0, size is 0" error. Here is my MainActicity.java file code:
import android.graphics.Canvas;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;
import com.joudi.myapplication.data.NoteItem;
import com.joudi.myapplication.data.NotesDataSource;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private NotesDataSource datasource;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
datasource = new NotesDataSource(this);
List<NoteItem> notes= datasource.findAll();
NoteItem note = notes.get(0);
note.setText("Updated!");
datasource.update(note);
notes= datasource.findAll();
note= notes.get(0);
Log.i("NOTES", note.getKey());
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

Looks looks datasource.findAll();returns an empty list.
notes.get(0); throws the exception.
You should check if the size of the list is greater then 0.
if (notes.size() >0){
NoteItem note = notes.get(0);
note.setText("Updated!");
datasource.update(note);
}

You need to check the size of notes before trying to access its element:
List<NoteItem> notes= datasource.findAll();
// Check the value of notes to avoid IndexOutOfBoundsException
if (null!=notes || notes.size()>0){
note = notes.get(0);
}

Header not getting set properly in android-Retrofit

I'm building an app for sending access-token to the server using Retrofit in android. I don't get any error what I think should set the header correctly is not working so.
The header that I want:
"Authorization: Bearer facebook <user_access_token>"
is the token that I get. Not written here for security purposes.
I am using android Retrofit for the purpose with the files as follows:
MainActivity.java
package com.example.apurva.myapplication;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.os.StrictMode;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
UserService userService;
String token = "Bearer facebook <user_access_token>";
userService = ServiceGenerator.createService(UserService.class, UserService.BASE_URL, token);
User user = userService.me();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
UserService.java
package com.example.apurva.myapplication;
import com.squareup.okhttp.OkHttpClient;
import retrofit.Callback;
import retrofit.RequestInterceptor;
import retrofit.RestAdapter;
import retrofit.client.OkClient;
import retrofit.http.POST;
/**
* Created by apurva on 4/8/15.
*/
public interface UserService {
public static final String BASE_URL = "http://10.0.2.2:8000/auth";
#POST("/convert-token")
User me();
}
ServiceGenerator.java
package com.example.apurva.myapplication;
import com.squareup.okhttp.OkHttpClient;
import retrofit.RequestInterceptor;
import retrofit.RestAdapter;
import retrofit.client.OkClient;
/**
* Created by apurva on 4/8/15.
*/
public class ServiceGenerator {
private ServiceGenerator() {
}
public static <S> S createService(Class<S> serviceClass, String baseUrl, final String token) {
RestAdapter.Builder builder = new RestAdapter.Builder()
.setEndpoint(baseUrl)
.setClient(new OkClient(new OkHttpClient()));
if (token != null) {
builder.setRequestInterceptor(new RequestInterceptor() {
#Override
public void intercept(RequestFacade request) {
request.addHeader("Accept", "application/json");
request.addHeader("Authorization", token);
}
});
}
RestAdapter adapter = builder.build();
return adapter.create(serviceClass);
}
}
I would like to mention that there are no errors. I have already set network activity in the main thread by using StrictMode so that is not an issue as well just it does not give the desired result as the user in not getting added in the backend.
I would also like to tel you that I've already checked my back end with cURL and it works fine so there is no issue there as well.
I get runtime error:
Process: com.example.apurva.myapplication, PID: 7140
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.apurva.myapplication/com.example.apurva.myapplication.MainActivity}: retrofit.RetrofitError: 405 METHOD NOT ALLOWED
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: retrofit.RetrofitError: 405 METHOD NOT ALLOWED
at retrofit.RestAdapter$RestHandler.invokeRequest(RestAdapter.java:388)
at retrofit.RestAdapter$RestHandler.invoke(RestAdapter.java:240)
at $Proxy0.me(Native Method)
at com.example.apurva.myapplication.MainActivity.onCreate(MainActivity.java:24)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

Your code is ok. You should add logging to your Retrofit.
// Simple add .setLogLevel(RestAdapter.LogLevel.FULL)
RestAdapter.Builder builder = new RestAdapter.Builder()
.setLogLevel(RestAdapter.LogLevel.FULL)
.setEndpoint(baseUrl)
.setClient(new OkClient(new OkHttpClient()));
I'm sure after this you will see in console:
---> HTTP POST http://10.0.2.2:8000/auth/convert-token
Accept: application/json
Authorization: Bearer facebook <user_access_token>
---> END HTTP (no body)
That means your header is set correctly.
"HTTP 405 METHOD NOT ALLOWED" may say that POST method is not expected for this resource. And maybe GET request will help you:
#GET("/convert-token")
User me();

Hi Please Refer githublink and it will give some Idea,let me explain basic functionality here,
Create a Interface:
public interface MyApiEndPointInterface {
/* #GET("contacts/")
Call<UserPojo> getHiveDetails();*/
#FormUrlEncoded
#POST("authorize/")
Call<SmsLogin> getUser(#Field("username") String username,
#Field("password") String password);
//GetProfile Details
#GET("getprofile")
Call<SmsProfilePojo> getProfileDetails(#Header("Authorizations") String myTokenValue);
}
UserProfilePreview.java is An Activity,Please LookUp this Class in repo,It give basic Idea.
private void getApiCAll() {
OkHttpClient okClient = new OkHttpClient.Builder() .addInterceptor(new Interceptor() {
#Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request().newBuilder()
.addHeader("Accept","Application/JSON").build();
return chain.proceed(request);
}
}).build();
retrofitRef = new Retrofit.Builder()
.baseUrl(BASE_URL)
.client(okClient)
.addConverterFactory(GsonConverterFactory.create())
.build();
final MyApiEndPointInterface service = retrofitRef.create(MyApiEndPointInterface.class);
String myTokenStr = "Bearer "+mToken;
Call<SmsProfilePojo> call = service.getProfileDetails(myTokenStr);
call.enqueue(new Callback<SmsProfilePojo>() {
#Override
public void onResponse(Call<SmsProfilePojo> call, retrofit2.Response<SmsProfilePojo> response) {
Log.d(TAG,"OnResponse: "+ response.code());
if(response.isSuccessful()){
SmsProfilePojo result = response.body();
mToken = result.getToken();
txtVw_Token.setText(mToken);
}else{
Toast.makeText(getApplicationContext(),"Fail in Response",Toast.LENGTH_SHORT).show();
}
}
#Override
public void onFailure(Call<SmsProfilePojo> call, Throwable t) {
Toast.makeText(getApplicationContext(),"Failed",Toast.LENGTH_SHORT).show();
}
});
}

Trying to save JSON string into a class to parce between activities (NPE)

I am trying to save my JSON string into a class so that I can pass around that object between activities and not lose any data when pressing the back button. However as I try to set the string into the object I receive a NullPointerException. Here is the code for my java file where the exception is occurring, the class java file, and the error. I am using GSON to serialize and deserialize. Any suggestions as to why this is happening?
NewLocation.java
package com.customledsupply.ledaudit;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Parcelable;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import com.google.gson.Gson;
public class NewLocation extends ActionBarActivity {
public EditText editCoName;
public EditText editCoAddress;
public EditText editCoContact;
public EditText editSqFt;
public EditText editTaxed;
public EditText editConcerns;
public JSON_String json;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_new_location);
findViewById(R.id.button3).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SaveInfo();
Intent i = new Intent(NewLocation.this, RoomList.class);
i.putExtra("json", (Parcelable) json);
startActivity(i);
}
});
editCoName = (EditText) findViewById(R.id.CoName);
editCoAddress = (EditText) findViewById(R.id.CoAddress);
editCoContact = (EditText) findViewById(R.id.CoContact);
editSqFt = (EditText) findViewById(R.id.SqFt);
editTaxed = (EditText) findViewById(R.id.Taxed);
editConcerns = (EditText) findViewById(R.id.Concerns);
SaveInfo();
}
#Override
protected void onResume() {
super.onResume();
LoadInfo();
}
#Override
protected void onDestroy() {
super.onDestroy();
SaveInfo();
}
public void SaveInfo() {
Gson gson = new Gson();
CompanyInfo companyInfo = new CompanyInfo();
companyInfo.setName(editCoName.getText().toString());
companyInfo.setAddress(editCoAddress.getText().toString());
companyInfo.setContact(editCoContact.getText().toString());
companyInfo.setTaxed(editTaxed.getText().toString());
companyInfo.setSqFt(editSqFt.getText().toString());
companyInfo.setConcerns(editConcerns.getText().toString());
json.setJson(gson.toJson(companyInfo));
SharedPreferences sharedPreferences = getApplicationContext().getSharedPreferences("json", MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("json", json.getJson());
editor.apply();
}
public void LoadInfo() {
SharedPreferences sharedPreferences = getApplicationContext().getSharedPreferences("json", MODE_PRIVATE);
json.setJson(sharedPreferences.getString("json", null));
Gson gson = new Gson();
CompanyInfo companyInfo = gson.fromJson(json.getJson(), CompanyInfo.class);
if (companyInfo != null) {
editCoName.setText(companyInfo.getName());
editCoAddress.setText(companyInfo.getAddress());
editCoContact.setText(companyInfo.getContact());
editTaxed.setText(companyInfo.getTaxed());
editSqFt.setText(companyInfo.getSqFt());
editConcerns.setText(companyInfo.getConcerns());
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_new_location, 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();
switch(item.getItemId())
{
case R.id.home:
startActivity(new Intent(getApplicationContext(), MainPage.class));
break;
}
return super.onOptionsItemSelected(item);
}
}
JSON_String.java
package com.customledsupply.ledaudit;
public class JSON_String {
private String json;
public void setJson(String json) {
this.json = json;
}
public String getJson() {
return json;
}
}
NPE error
08-03 08:46:52.081 24423-24423/com.customledsupply.ledaudit E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.customledsupply.ledaudit, PID: 24423
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.customledsupply.ledaudit/com.customledsupply.ledaudit.NewLocation}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2248)
at android.app.ActivityThread.access$800(ActivityThread.java:138)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5061)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:780)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:596)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.customledsupply.ledaudit.NewLocation.SaveInfo(NewLocation.java:78)
at com.customledsupply.ledaudit.NewLocation.onCreate(NewLocation.java:52)
at android.app.Activity.performCreate(Activity.java:5237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2248)
            at android.app.ActivityThread.access$800(ActivityThread.java:138)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1199)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5061)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:780)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:596)
            at dalvik.system.NativeStart.main(Native Method)

You're trying to cast your json to Parcelable:
i.putExtra("json", (Parcelable) json);
Just pass as a string and in your RoomList.class get from bundle. Cast it to your class with gson and use it.

Your json is null, hence the error. To onCreate add
json = new JSON_String();
If you want to keep passing the object between activites, and not lose it when back button is pressed, you should use startActivityForResults(). This will require you to implement a couple of methods that take care of passing objects between activities. This is a good tutorial.

The problem is You didn't initialize your JSON_String class. You need to initialize the JSON_String like
public JSON_String json = new JSON_String();

Have you tried to initlize the json string?

Android MediaRecorder NullPointerException

Im just starting out with Java Development and i am fiddling around with the Android Media recorder. However I am getting a NullPointerException which I click the record button using the following source code:
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
//import android.net.Uri;
import android.view.Menu;
import android.view.MenuItem;
import android.os.Environment;
import android.view.View;
import java.io.File;
import java.io.IOException;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import java.lang.String;
public class MainActivity extends ActionBarActivity {
String outputFile = "test.3gp";
private MediaRecorder myAudioRecorder;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MediaRecorder myAudioRecorder = new MediaRecorder();
myAudioRecorder = new MediaRecorder();
// Uri target = Uri.parse(outputFile.getAbsolutePath());
myAudioRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
myAudioRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
myAudioRecorder.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
myAudioRecorder.setOutputFile(outputFile);
}
public void Start_Record(View v)
{
try {
myAudioRecorder.prepare();
myAudioRecorder.start();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
myAudioRecorder.stop();
myAudioRecorder.release();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
I realise that this probably due to the fill pointer being set to NULL, however I am struggling to see how to initialize the file reference for this to vanish. I am getting th exception on mediaRecorderPrepare()
Here is the Exception thrown:
03-09 22:53:56.548 31836-31836/uk.co.spectralgear.spectralboost E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:4007)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaRecorder.prepare()' on a null object reference
at uk.co..MainActivity.Start_Record(MainActivity.java:38)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Any help would be greatly appreciated:)

PROBLEM:
Your class variable "myAudioRecord" is null when "Start_Record()" tries to use it:
Caused by: java.lang.NullPointerException:
Attempt to invoke virtual method 'void Android.media.MediaRecorder.prepare()' on a null object reference
SOLUTION: Delete this line from your "onCreate()" method:
public class MainActivity extends ActionBarActivity {
String outputFile = "test.3gp";
private MediaRecorder myAudioRecorder; // Your class variable: OK...
#Override
protected void onCreate(Bundle savedInstanceState) {
...
// MediaRecorder myAudioRecorder = new MediaRecorder(); // DELETE THIS LINE!!!
myAudioRecorder = new MediaRecorder(); // OK...
...
The declaration of "myAudioRecorder" inside onCreate() HIDES the outer declaration. So the outer (class-level) "myAudioRecorder" never gets initialized ... and your program dies with an NPE when "Start_Record()" tries to access it.
PS:
Please consider changing the method name to "start_Record()". Or better, "startRecord()". This is more consistent with Java naming conventions.

I think you are using stop() function while it was already stopped. Check your code and logic.

Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first

Guys I am getting an error and I am not sure how to solve it please help me.
Here is my code:
package com.appschool.www.projectphase1516;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.Switch;
import android.widget.TextView;
import com.appschool.www.projectphase1516.R;
import org.w3c.dom.Text;
public class AccountlistActivity extends Activity implements View.OnClickListener {
LinearLayout horiz;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_accountlist);
horiz = (LinearLayout) findViewById(R.id.linearlayouthere);
Accountlistcreator();
setContentView(horiz);
}
public void Accountlistcreator(){
SharedPreferences sp = getSharedPreferences("details",1);
int numofaccounts = sp.getInt("numofaccouns",0);
horiz.removeAllViews();
for(int i=0;i<=numofaccounts;i++) {
TextView titleaccount = new TextView(this);
titleaccount.setText(sp.getString("accountTitle" + i, ""));
titleaccount.setTextSize(20);
horiz.addView(titleaccount);
Button seeaccount = new Button(this);
seeaccount.setText("See Details");
seeaccount.setId(i);
seeaccount.setLayoutParams(new FrameLayout.LayoutParams(200,100));
seeaccount.setOnClickListener(this);
horiz.addView(seeaccount);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.accountlist, 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);
}
#Override
public void onClick(View view) {
SharedPreferences sp = getSharedPreferences("details",1);
int num = sp.getInt("numofaccouns",0);
for(int x=0;x<=num;x++){
if(view.getId()==x){
Intent myaccount = new Intent(AccountlistActivity.this,MyaccountActivity.class);
myaccount.putExtra("numbtn",x);
startActivity(myaccount);
}
}
}
}
And here is the error I am getting:
Process: com.appschool.www.projectphase1516, PID: 2751
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.appschool.www.projectphase1516/com.appschool.www.projectphase1516.AccountlistActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.view.ViewGroup.addViewInner(ViewGroup.java:3562)
at android.view.ViewGroup.addView(ViewGroup.java:3415)
at android.view.ViewGroup.addView(ViewGroup.java:3391)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:309)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:299)
at android.app.Activity.setContentView(Activity.java:1949)
at com.appschool.www.projectphase1516.AccountlistActivity.onCreate(AccountlistActivity.java:29)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)
Please help me out guys!
The code should create a specific number of buttons and textviews.
I am trying to remove and recreate all of them everytime I am going to that activity and am not sure why I keep getting an error :[
EDIT:
thanks it now runs but there is another problem
it doesnt create more than 1 textview and a button and i am not sure why
(i am pretty new to java development,so i dont know complex features like the comment above me ) i am just doing homework :P

Remove the
setContentView(horiz);
horiz is already a part of the activity's content view.

Your approach is wrong, you want to fill your layout with a lot of information by creating multiple textviews to show information, what you need is a list view and a custom list adapter, so you can get from your shared preferences info you will save in a list, and then pass it to the adapter so the adapter can build all the views you want and doing it better and easier than your approach.

First answer: horiz already has a parent (it's already part of the contentview which you set). Remove setContentView(horiz)
To answer your second question:
SharedPreferences sp = getSharedPreferences("details",1);
int numofaccounts = sp.getInt("numofaccouns",0);
Which means you get sharedpreferences (details) with entry numofaccouns. That one doesnt exist, however, because you never save it. You only get a non-existing entry, and if that one doesnt exist, you default it to 0. The forloop is initialized like for (int i = 0; i <= numofaccouns; i++) which means you always hit index i == 0, because numofaccouns is always 0
final String SHARED_PREFS = "details";
final String NUMBER_OF_ACCOUNTS = "numberOfAccounts";
final int NUMBER_OF_ACCOUNTS_DEFAULT = 10;
int numberOfAccounts = 75;
//to save into sharedpreferences:
getSharedPreferences(SHARED_PREFS, MODE_PRIVATE).edit().put(NUMBER_OF_ACCOUNTS, numberOfAccounts).commit();
//to retrieve that value:
numberOfAccounts = getSharedPreferences(SHARED_PREFS, MODE_PRIVATE).getInt(NUMBER_OF_ACCOUNTS, NUMBER_OF_ACCOUNTS_DEFAULT);
saving all the accounts et cetera can be done in exactly the same manner as the example given above.