I have this problem I want to pass a raw from Activity 1 to be played in Activity 2
Here is my code
Activity 1
package com.ze.zeggar.tewt;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class Main2Activity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
int ThePlayedSound= R.raw.waterdrop;
Intent MyIntent= new Intent(this, MainActivity.class);
MyIntent.putExtra("key",ThePlayedSound);
startActivity(MyIntent);
}
}
Activity 2
package com.ze.zeggar.tewt;
import android.content.Intent;
import android.media.AudioManager;
import android.media.SoundPool;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
Button button;
SoundPool Sound_Pool_thing;
int Click;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent MyIntent=getIntent();
int ThePlayedSound= MyIntent.getIntExtra("key", 0);
Sound_Pool_thing= new SoundPool(1, AudioManager.STREAM_MUSIC,0);
Click = Sound_Pool_thing.load(this,ThePlayedSound , 1);
button=(Button)findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Sound_Pool_thing.play(Click,1,1,1,0,1);
}
});
}
}
and when I try to open the app I got "Unfortunately , My_App has stopped"
The app crashes
and here's the new crash Log after suggestions:
06-06 10:49:09.069 3424-3424/com.ze.zeggar.tewt E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.ze.zeggar.tewt, PID: 3424
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ze.zeggar.tewt/com.ze.zeggar.tewt.MainActivity}:
android.content.res.Resources$NotFoundException: Resource ID #0x0
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2365)
at android.app.ActivityThread.access$800(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5272)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
Caused by: android.content.res.Resources$NotFoundException: Resource ID #0x0
at android.content.res.Resources.getValue(Resources.java:1269)
at android.content.res.Resources.openRawResourceFd(Resources.java:1227)
at android.media.SoundPool$SoundPoolImpl.load(SoundPool.java:566)
at android.media.SoundPool.load(SoundPool.java:229)
at com.ze.zeggar.tewt.MainActivity.onCreate(MainActivity.java:28)
at android.app.Activity.performCreate(Activity.java:5977)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2258)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2365)
at android.app.ActivityThread.access$800(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5272)
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:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
Any idea ?
Ur getting resource not found exception since your not opening the raw type Resources properly
Try getting the raw audio file from resources like this:
int ThePlayedSound = this.getResources().getIdentifier("waterdrop", "raw", getPackageName());
Intent MyIntent= new Intent(this, MainActivity.class);
MyIntent.putExtra("key",ThePlayedSound);
startActivity(MyIntent);
What about using the MediaPlayer class?
Check this code below:
MainActivity class (or whatever class you want to start the new activity from)
Intent intent = new Intent(this,Main2Activity.class);
intent.putExtra("key",R.raw.waterdrop);
startActivity(intent);
Main2Activity (class that will play the audio)
public class Main2Activity extends AppCompatActivity {
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activitiy_main2);
int soundId = getIntent().getIntExtra("key",0);
final MediaPlayer mPlayer =new MediaPlayer();
mPlayer.setAudioSessionId(soundId);
mPlayer.setLooping(true);
Button button = (Button)findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mPlayer.start();
}
});
}
}
This code worked for me.
If it says that that specific constructor doesnt work try the below one:
final MediaPlayer mPlayer =new MediaPlayer(this,soundId);
Hope it helps you out!
Related
I have just begun writing some code for my Chat app after days of planning but the problem is that keeps on crashing right after the Gradle Build has finished and the app is installed on my device. I have created a button that is expected to open a new activity but instead of doing so it crashes. Everything works before I have written any code, the app opens and logcat doesn't show any errors. Here is the error:
2022-08-10 19:26:48.372 15348-15348/? E/e.myapplicatio: Unknown bits set in runtime_flags: 0x40000000
2022-08-10 19:26:48.391 15348-15348/? E/RefClass: java.lang.reflect.InvocationTargetException
2022-08-10 19:26:48.474 15348-15348/com.example.myapplication E/Perf: perftest packageName : com.example.myapplication App is allowed to use Hide APIs
2022-08-10 19:26:48.515 15348-15374/com.example.myapplication E/libEGL: Invalid file path for libcolorx-loader.so
2022-08-10 19:26:48.528 15348-15348/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 15348
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3628)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3887)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2317)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:263)
at android.app.ActivityThread.main(ActivityThread.java:8292)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:612)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1006)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:183)
at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:174)
at android.content.Context.obtainStyledAttributes(Context.java:744)
at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:848)
at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:815)
at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:640)
at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:259)
at com.example.myapplication.MainActivity.<init>(MainActivity.java:12)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
at android.app.Instrumentation.newActivity(Instrumentation.java:1254)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3616)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3887)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:100)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2317)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:263)
at android.app.ActivityThread.main(ActivityThread.java:8292)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:612)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1006)
I tried following some other suggestions but they didn't work. Here's the snippet of my code:
package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
public Button signUp = findViewById(R.id.signUpBtn);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
signUp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
openActivity();
}
});
}
public void openActivity(){
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
}
}
You can not use findViewById() outside of onCreate() like this and if you really wanna do that, do it by creating a new method for setting up IDs and then add that method in onCreate().
this code will do the work now:
package com.example.myapplication;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.view.View;
import android.widget.Button;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
public Button signUp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
signUp = findViewById(R.id.signUpBtn);
signUp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
openActivity();
}
});
}
public void openActivity(){
Intent intent = new Intent(this, LoginActivity.class);
startActivity(intent);
}
}
I am learning how to develop for Android (and development in general). I am trying to create a Quiz App, so I can learn the basics.
While trying to use an Intent to go to another class with an extra variable on it, I found this problem (which I think is pretty usual): My app crashes when I go to the next Activity.
This is the code in the activity that gets the username ("usuario and nomeUsuario"):
package com.isa56.quiz2;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import androidx.appcompat.app.AppCompatActivity;
public class HomeActivity extends AppCompatActivity {
public EditText usuario;
public EditText senha;
public Button botaoLogin;
public String nomeUsuario;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
botaoLogin = findViewById(R.id.botaoLogin);
senha = findViewById(R.id.senha);
usuario = findViewById(R.id.usuario);
nomeUsuario = usuario.getText().toString();
Log.d("nome de usuario", nomeUsuario);
botaoLogin.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
Intent i = new Intent(HomeActivity.this, FirstQuestionActivity.class);
i.putExtra("nome", nomeUsuario);
startActivity(i);
}});
}
}
And this is the code on the SecondQuestionActivity:
package com.isa56.quiz2;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class FirstQuestionActivity extends AppCompatActivity {
public Button prox1;
public Button respUm1;
public Button respUm2;
public TextView texto1;
public int pontuacao = 0;
Intent i = getIntent();
String nome = i.getStringExtra("nome");
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_firstquestion);
prox1 = findViewById(R.id.prox1);
respUm1 = findViewById(R.id.botao1a);
respUm2 = findViewById(R.id.botao1b);
texto1 = findViewById(R.id.texto1);
respUm1.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
texto1.setText("Resposta errada!");
respUm1.setEnabled(false);
respUm2.setEnabled(false);
prox1.setEnabled(true);
}});
respUm2.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
texto1.setText("Resposta certa!");
respUm2.setEnabled(false);
respUm1.setEnabled(false);
pontuacao += 1;
prox1.setEnabled(true);
}});
prox1.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
Intent i = new Intent(FirstQuestionActivity.this, SecondQuestionActivity.class);
i.putExtra("pontos", pontuacao);
i.putExtra("nome", nome);
startActivity(i);
}
});
}
}
What is wrong with it? How can I prevent it?
Thank you!
P.S.: I am not used to forum or development in general, so I might have done this wrongly. I'm sorry.
Edit: Also, if anyone wanna take a look at the whole project, it's here.
Edit2: This is the Logcat output:
2020-11-13 21:05:18.531 7517-7517/com.isa56.quiz2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.isa56.quiz2, PID: 7517
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.isa56.quiz2/com.isa56.quiz2.FirstQuestionActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference
at com.isa56.quiz2.FirstQuestionActivity.<init>(FirstQuestionActivity.java:18)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
at android.app.Instrumentation.newActivity(Instrumentation.java:1253)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Keep these lines inside onCreate() method.
Intent i = getIntent();
String nome = i.getStringExtra("nome");
When my SplashActivity opens the LoginActivity my app crashes.
The following is my SplashActivity.java:
package com.example.android.appName;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import java.util.Timer;
import java.util.TimerTask;
public class SplashActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
Timer timer = new Timer();
timer.schedule(new TimerTask() {
public void run() {
Intent intent = new Intent(SplashActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
}, 1500);
}
}
and my LoginActivity.java:
package com.example.android.appName;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
public class LoginActivity extends AppCompatActivity {
private EditText usernameField = (EditText)findViewById(R.id.username),
passwordField = (EditText)findViewById(R.id.password);
private TextView error = (TextView)findViewById(R.id.error);
private ProgressBar progress = (ProgressBar)findViewById(R.id.progress);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.login_menu, menu);
return true;
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (android.os.Build.VERSION.SDK_INT > 5
&& keyCode == KeyEvent.KEYCODE_BACK
&& event.getRepeatCount() == 0) {
onBackPressed();
return true;
}
return super.onKeyDown(keyCode, event);
}
public void exit(MenuItem item) {
finish();
}
public void signIn(View view) {
Intent intent = new Intent(this, MainActivity.class);
startActivity(intent);
finish();
}
}
Part of AndroidManifest.xml:
<activity android:name=".SplashActivity"
android:theme="#style/NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".LoginActivity"
android:label="#string/title_activity_login" />
Error in logcat:
04-16 23:24:16.124 4015-4015/com.example.android.appName E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.appName, PID: 4015
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.android.appName/com.example.android.appName.LoginActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2993)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3248)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1681)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6872)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:68)
at android.support.v7.app.AppCompatDelegateImplV7.<init>(AppCompatDelegateImplV7.java:145)
at android.support.v7.app.AppCompatDelegateImplV11.<init>(AppCompatDelegateImplV11.java:28)
at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:42)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:186)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:168)
at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:508)
at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:180)
at com.example.android.appName.LoginActivity.<init>(LoginActivity.java:20)
at java.lang.reflect.Constructor.newInstance(Native Method)
at java.lang.Class.newInstance(Class.java:1690)
at android.app.Instrumentation.newActivity(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2983)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3248)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1681)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6872)
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:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
An Activity is not fully initialized and ready to look up views until after setContentView(...) is called in onCreate().
Only declare the fields like the following:
private EditText usernameField, passwordField;
private TextView error;
private ProgressBar progress;
and then assign the values in onCreate:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
usernameField = (EditText)findViewById(R.id.username);
passwordField = (EditText)findViewById(R.id.password);
error = (TextView)findViewById(R.id.error);
progress = (ProgressBar)findViewById(R.id.progress);
}
Might not be part of the problem but as an extra bit of advice a Timer runs the TimerTask on a background thread and that should be avoided in this case. Replace the Timer with a Handler instead to run it on the UI thread.
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
Intent intent = new Intent(SplashActivity.this, LoginActivity.class);
startActivity(intent);
finish();
}
}, 1500);
Views defined in xml file can only be accessed in java code, after setting the ContentView as the required xml file using:
setContentView(R.layout.xml_file_name);
So 1st call above method inside onCreate method and then initialize the View instances inside onCreate or inside the methods in which the instance will be used.
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 4 years ago.
Hello my question is about my app is crash after I am trying to hit next fragment.
Code is compiling but i don't know how to solve this problem.
Something with onclicklistner.
I tried some solutions but didn't succeed.
This is my code:
ProfileFragment.java
package com.statusionew.statusio.fragments;
import android.app.ProgressDialog; import android.content.Intent; import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v7.widget.Toolbar; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button;
import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.auth.FirebaseUser; import com.statusionew.statusio.ForgetchangePasswordActivity; import com.statusionew.statusio.LoginActivity; import com.statusionew.statusio.R; import com.statusionew.statusio.MainActivity;
import butterknife.BindView; import butterknife.ButterKnife; import butterknife.OnClick;
public class ProfileFragment extends BaseFragment implements View.OnClickListener{
FirebaseAuth auth;
FirebaseUser user;
ProgressDialog PD;
#BindView(R.id.sign_out_button) Button btnSignOut;
#BindView(R.id.change_password_button) Button btnChangePass;
#BindView(R.id.change_email_button) Button btnChangeEmail;
#BindView(R.id.delete_user_button) Button btnDeleteUser;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.activity_setting, container, false);
ButterKnife.bind(getActivity(), view);
((MainActivity) getActivity()).updateToolbarTitle("Profile");
return view;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
auth = FirebaseAuth.getInstance();
user = auth.getCurrentUser();
PD = new ProgressDialog(getActivity());
PD.setMessage("Loading...");
PD.setCancelable(true);
PD.setCanceledOnTouchOutside(false);
btnSignOut.setOnClickListener(new View.OnClickListener() {
#Override
#OnClick(R.id.sign_out_button)
public void onClick(View view) {
auth.signOut();
FirebaseAuth.AuthStateListener authListener = new FirebaseAuth.AuthStateListener() {
#Override
public void onAuthStateChanged(#NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user == null) {
Intent intent = new Intent(getActivity(), LoginActivity.class);
startActivity(intent);
}
}
};
}
});
btnChangePass.setOnClickListener(new View.OnClickListener() {
#Override
#OnClick(R.id.change_password_button)
public void onClick(View view) {
startActivity(new Intent(getActivity().getApplicationContext(), ForgetchangePasswordActivity.class).putExtra("Mode", 1));
}
});
btnChangeEmail.setOnClickListener(new View.OnClickListener() {
#Override
#OnClick(R.id.change_email_button)
public void onClick(View view) {
startActivity(new Intent(getActivity().getApplicationContext(), ForgetchangePasswordActivity.class).putExtra("Mode", 2));
}
});
btnDeleteUser.setOnClickListener(new View.OnClickListener() {
#Override
#OnClick(R.id.delete_user_button)
public void onClick(View view) {
startActivity(new Intent(getActivity().getApplicationContext(), ForgetchangePasswordActivity.class).putExtra("Mode", 3));
}
});
}
#Override
public void onClick(View v) {
if (auth.getCurrentUser() == null) {
startActivity(new Intent(getActivity(), LoginActivity.class));
getActivity().finish();
}
super.onResume();
} }
this the log that say 'Attempt to invoke virtual method'-
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.statusionew.statusio, PID: 9206
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.statusionew.statusio.fragments.ProfileFragment.onCreate(ProfileFragment.java:65)
at android.support.v4.app.Fragment.performCreate(Fragment.java:2339)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1377)
at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1109)
at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:996)
at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:99)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2364)
at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2322)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2229)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:781)
at com.statusionew.statusio.views.FragNavController.executePendingTransactions(FragNavController.java:631)
at com.statusionew.statusio.views.FragNavController.switchTab(FragNavController.java:142)
at com.statusionew.statusio.views.FragNavController.switchTab(FragNavController.java:158)
at com.statusionew.statusio.MainActivity.switchTab(MainActivity.java:149)
at com.statusionew.statusio.MainActivity.access$100(MainActivity.java:30)
at com.statusionew.statusio.MainActivity$1.onTabSelected(MainActivity.java:87)
at android.support.design.widget.TabLayout.dispatchTabSelected(TabLayout.java:1165)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1158)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1128)
at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1427)
at android.support.design.widget.TabLayout$TabView.performClick(TabLayout.java:1537)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Connected to process 10580 on device emulator-5554
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
I/art: Not late-enabling -Xcheck:jni (already on)
W/art: Unexpected CPU variant for X86 using defaults: x86
W/System: ClassLoader referenced unknown path: /data/app/com.statusionew.statusio-1/lib/x86
D/FirebaseApp: com.google.firebase.crash.FirebaseCrash is not linked. Skipping initialization.
V/FA: Registered activity lifecycle callback
I/FirebaseInitProvider: FirebaseApp initialization successful
I/InstantRun: starting instant run server: is main process
E/InstantRun: IO Error creating local socket at com.statusionew.statusio
java.io.IOException: Address already in use
at android.net.LocalSocketImpl.bindLocal(Native Method)
at android.net.LocalSocketImpl.bind(LocalSocketImpl.java:308)
at android.net.LocalServerSocket.<init>(LocalServerSocket.java:48)
at com.android.tools.ir.server.Server.<init>(Server.java:91)
at com.android.tools.ir.server.Server.create(Server.java:85)
at com.android.tools.ir.server.InstantRunContentProvider.onCreate(InstantRunContentProvider.java:49)
at android.content.ContentProvider.attachInfo(ContentProvider.java:1751)
at android.content.ContentProvider.attachInfo(ContentProvider.java:1726)
at android.app.ActivityThread.installProvider(ActivityThread.java:5853)
at android.app.ActivityThread.installContentProviders(ActivityThread.java:5445)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5384)
at android.app.ActivityThread.-wrap2(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1545)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
It seems like you've got some misunderstandings about how Fragments and ButterKnife work.
OnCreate is called BEFORE onCreateView in a Fragment. So all your views are null when you're trying to access them in onCreate.
See Fragment Lifecycle:
https://www.tutorialspoint.com/android/images/fragment.jpg
OnCreate is not used that much in Fragments, onCreateView is used more.
Your ButterKnife bind code is also wrong. You're trying to bind the Activity to the views in the Fragment.
See ButterKnife documentation for correct usage: http://jakewharton.github.io/butterknife/
I am facing the problem when I use Intent to send a value to another activity by click a button. I have tried to solve it in many ways but it always show NullPointerException although I declared it clearly.
Here is my code.
Manufacturer.java
package com.example.student.macheckcar;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
public class Manufacturer extends AppCompatActivity {
public String message;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manufacturer);
Button toyota = (Button) findViewById(R.id.Toyota);
Button subaru = (Button) findViewById(R.id.Subaru);
Button audi = (Button) findViewById(R.id.Audi);
toyota.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Toyota";
goAnother(message.toString());
}
});
subaru.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Subaru";
goAnother(message);
}
});
audi.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
message = "Audi";
goAnother(message);
}
});
}
protected void goAnother(String brand){
Intent i = new Intent(Manufacturer.this, ShowCarPrice.class);
i.putExtra("brand", brand);
startActivity(i);
}
}
Showcarprice.java
package com.example.student.macheckcar;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.view.Window;
import java.util.ArrayList;
public class ShowCarPrice extends AppCompatActivity {
private Cursor cursor;
private ArrayList<String> price;
private ArrayAdapter<String> aa;
private DBprice dbPrice;
private Manufacturer maFact;
SQLiteDatabase db;
ListView list;
Intent intent = getIntent();
String brand = intent.getStringExtra("brand");
#Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_car_price);
list = (ListView) findViewById(R.id.listView);
dbPrice = new DBprice(this);
db = dbPrice.getWritableDatabase();
cursor = db.rawQuery("SELECT " + dbPrice.KEY_TASK + " FROM " + dbPrice.TABLE_NAME + " WHERE Manufacturer = ?", new String[] {brand});
price = new ArrayList<String>();
cursor.moveToFirst();
while ( !cursor.isAfterLast() ){
price.add(cursor.getString(cursor.getColumnIndex(dbPrice.KEY_TASK)));
cursor.moveToNext();
}
aa = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, price);
list.setAdapter(aa);
}
public void onPause() {
super.onPause();
dbPrice.close();
db.close();
}
}
And the error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.student.macheckcar, PID: 934
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.student.macheckcar/com.example.student.macheckcar.ShowCarPrice}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
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: java.lang.NullPointerException
at com.example.student.macheckcar.ShowCarPrice.<init>(ShowCarPrice.java:22)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1208)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2101)
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)
Please help.
UPDATE
public class ShowCarPrice extends AppCompatActivity {
// OK, Create the objects, variables here if needed
Intent intent;
String brand;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_activity_layout);
// You should assign the intent here (in onCreate method)
intent = getIntent();
// Then, the string variable
brand = intent.getStringExtra("brand");
// You can also check whether or not received a valid value
if (brand != null && !brand.isEmpty())
// do something with brand value
else
// brand value is null or empty
}
}
Well, you call getIntent() at the wrong position. You should call getIntent() in method onCreate() , and I don't know why you keep intent as a member of your activity. If I were you I just do
String brand = getIntent().getStringExtra("brand");
in onCreate() method.
get your intent and extras of intent in onCreate() method of activity just check below link for this
https://stackoverflow.com/a/5265952/5316836