Java Android application quickly closes after opening
Question
A while ago, i had the main login/signup screen and the drawer working, but when i tried to implement a item database, which class while implemented i did not instantiate or call anywhere, still the app stopped working, it would open and quickly close, the mobile would report that "The app was presenting continuous failures" even without changing the business rules or model.
This my launch activity the MainActivity which is the SignIn
package com.example.appteste;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;
import com.example.appteste.ui.login.LoginActivity;
import com.github.mikephil.charting.charts.PieChart;
import com.github.mikephil.charting.data.PieData;
import com.github.mikephil.charting.data.PieDataSet;
import com.github.mikephil.charting.data.PieEntry;
import com.github.mikephil.charting.utils.ColorTemplate;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.auth.UserProfileChangeRequest;
import java.util.ArrayList;
import lecho.lib.hellocharts.model.PieChartData;
import static android.content.ContentValues.TAG;
public class MainActivity extends AppCompatActivity {
private FirebaseAuth mAuth;
// private PieChart pieChart;w
final Button signUpButton = findViewById(R.id.createUserButton);
final EditText displayNameEditText = findViewById(R.id.name_field);
final EditText usernameEditText = findViewById(R.id.mail_field);
final EditText passwordEditText = findViewById(R.id.password_field);
final Button login = findViewById(R.id.login);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// sets the .xml current view
setContentView(R.layout.activity_sign_in);
// pie start
// pieChart = findViewById(R.id0
// pie end
// getEntries();
// declarations
mAuth = FirebaseAuth.getInstance();
signUpButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// calls createAccount
createAccount(displayNameEditText.getText().toString(), usernameEditText.getText().toString(), passwordEditText.getText().toString());
// logs in the system that
Log.v("signUp", "UserSignedUp:"+ usernameEditText.getText().toString() + "password: " + passwordEditText.getText().toString());
// Logs in the created user
mAuth.signInWithEmailAndPassword(usernameEditText.getText().toString(),
passwordEditText.getText().toString())
.addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
// startActivity(new Intent(MainActivity.this, MenuActivity.class));
startActivity(new Intent(MainActivity.this, HomeActivity.class));
} else {
Toast.makeText(MainActivity.this, task.getException().getMessage(), Toast.LENGTH_LONG).show();
}
}
});
// supposed to show a welcome message
// updateUiWithUser(mAuth.getCurrentUser());
// shows message to user? maybe?
Toast.makeText(MainActivity.this, "Register Succeed.",
Toast.LENGTH_SHORT).show();
}
});
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// change to Login screen
startActivity(new Intent(MainActivity.this, LoginActivity.class));
}
});
}
public void createAccount(final String displayName, String email, String password) {
mAuth.createUserWithEmailAndPassword(email, password)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
// Sign in success, update UI with the signed-in user's information
Log.d(TAG, "createUserWithEmail:success");
FirebaseUser user = mAuth.getCurrentUser();
// sets the display Name for the user
user.updateProfile(new UserProfileChangeRequest.Builder().setDisplayName(displayName).build());
startActivity(new Intent(MainActivity.this, LoginActivity.class));
updateUiWithUser();
} else {
// If sign in fails, display a mcessage to the user.
Log.w(TAG, "createUserWithEmail:failure", task.getException());
Toast.makeText(MainActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
// updateUiWithUser(null);
}
// TODO discover what to add here
}
});
}
private void updateUiWithUser(FirebaseUser model) {
String welcome = getString(R.string.welcome) + model.getDisplayName();
// TODO : initiate successful logged in experience
Toast.makeText(getApplicationContext(), welcome, Toast.LENGTH_LONG).show();
}
private void updateUiWithUser() {
String welcome = getString(R.string.welcome) + mAuth.getCurrentUser().getDisplayName();
// TODO : initiate successful logged in experience
Toast.makeText(getApplicationContext(), welcome, Toast.LENGTH_LONG).show();
}
}
LoginActivity(where the MainActivity goes after registering )
package com.example.appteste.ui.login;
import android.app.Activity;
import androidx.annotation.NonNull;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProviders;
import android.content.Intent;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.annotation.StringRes;
import androidx.appcompat.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.example.appteste.HomeActivity;
import com.example.appteste.MenuActivity;
import com.example.appteste.R;
import com.example.appteste.ui.login.LoginViewModel;
import com.example.appteste.ui.login.LoginViewModelFactory;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import static android.content.ContentValues.TAG;
public class LoginActivity extends AppCompatActivity {
private LoginViewModel loginViewModel;
private FirebaseAuth mAuth;
private LoginResult login;
public LoginResult getLogin() {
return login;
}
public void setLogin(LoginResult login) {
this.login = login;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
loginViewModel = ViewModelProviders.of(this, new LoginViewModelFactory())
.get(LoginViewModel.class);
final EditText usernameEditText = findViewById(R.id.username);
final EditText passwordEditText = findViewById(R.id.password);
final Button loginButton = findViewById(R.id.login);
final ProgressBar loadingProgressBar = findViewById(R.id.loading);
mAuth = FirebaseAuth.getInstance();
loginViewModel.getLoginFormState().observe(this, new Observer<LoginFormState>() {
@Override
public void onChanged(@Nullable LoginFormState loginFormState) {
if (loginFormState == null) {
return;
}
loginButton.setEnabled(loginFormState.isDataValid());
if (loginFormState.getUsernameError() != null) {
usernameEditText.setError(getString(loginFormState.getUsernameError()));
}
if (loginFormState.getPasswordError() != null) {
passwordEditText.setError(getString(loginFormState.getPasswordError()));
}
}
});
loginViewModel.getLoginResult().observe(this, new Observer<LoginResult>() {
@Override
public void onChanged(@Nullable LoginResult loginResult) {
if (loginResult == null) {
return;
}
loadingProgressBar.setVisibility(View.GONE);
if (loginResult.getError() != null) {
setLogin(loginResult);
showLoginFailed(loginResult.getError());
}
if (loginResult.getSuccess() != null) {
// updateUiWithUser(loginResult.getSuccess());
}
setResult(Activity.RESULT_OK);
//Complete and destroy login activity once successful
finish();
}
});
TextWatcher afterTextChangedListener = new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
// ignore
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
// ignore
}
@Override
public void afterTextChanged(Editable s) {
loginViewModel.loginDataChanged(usernameEditText.getText().toString(),
passwordEditText.getText().toString());
}
};
usernameEditText.addTextChangedListener(afterTextChangedListener);
passwordEditText.addTextChangedListener(afterTextChangedListener);
passwordEditText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
@Override
public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
if (actionId == EditorInfo.IME_ACTION_DONE) {
loginViewModel.login(usernameEditText.getText().toString(),
passwordEditText.getText().toString());
}
return false;
}
});
loginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mAuth.signInWithEmailAndPassword(usernameEditText.getText().toString(),
passwordEditText.getText().toString())
.addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
updateUiWithUser(mAuth.getCurrentUser());
// startActivity(new Intent(LoginActivity.this, MenuActivity.class));
startActivity(new Intent(LoginActivity.this, HomeActivity.class));
} else {
Toast.makeText(LoginActivity.this, task.getException().getMessage(), Toast.LENGTH_LONG).show();
}
}
});
}
});
}
// [START on_start_check_user]
@Override
public void onStart() {
super.onStart();
// Check if user is signed in (non-null) and update UI accordingly.
FirebaseUser currentUser = mAuth.getCurrentUser();
// updateUiWithUser(getLogin().getSuccess());
updateUiWithUser(currentUser);
}
// [END on_start_check_user]
private void updateUiWithUser(FirebaseUser user) {
String welcome = getString(R.string.welcome) + user.getDisplayName();
// TODO : initiate successful logged in experience
Toast.makeText(getApplicationContext(), welcome, Toast.LENGTH_LONG).show();
}
private void showLoginFailed(@StringRes Integer errorString) {
Toast.makeText(getApplicationContext(), errorString, Toast.LENGTH_SHORT).show();
}
}
my logcat:
2019-10-24 16:39:39.723 711-711/? E/Zygote: isWhitelistProcess - Process is Whitelisted
2019-10-24 16:39:39.723 711-711/? E/Zygote: accessInfo : 1
2019-10-24 16:39:40.209 711-711/com.example.appteste E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.appteste, PID: 711
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.appteste/com.example.appteste.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:3019)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3256)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1947)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7037)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
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:164)
at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:157)
at android.content.Context.obtainStyledAttributes(Context.java:677)
at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:692)
at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:659)
at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:479)
at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:214)
at com.example.appteste.MainActivity.<init>(MainActivity.java:42)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:41)
at android.app.Instrumentation.newActivity(Instrumentation.java:1215)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3007)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3256)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1947)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7037)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
2 answers
solution1
0 2019-10-24 19:51:49
Button signUpButton;
EditText displayNameEditText;
EditText usernameEditText;
EditText passwordEditText;
Button login;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// sets the .xml current view
setContentView(R.layout.activity_sign_in);
signUpButton = findViewById(R.id.createUserButton);
displayNameEditText = findViewById(R.id.name_field);
usernameEditText = findViewById(R.id.mail_field);
passwordEditText = findViewById(R.id.password_field);
login = findViewById(R.id.login);
solution2
0 2019-10-24 21:56:54
You are trying to inflate your views upon class initialization and not in the corresponding life cycle method. As ANDRE OLIVERA suggested, move
final Button signUpButton = findViewById(R.id.createUserButton);
final EditText displayNameEditText = findViewById(R.id.name_field);
final EditText usernameEditText = findViewById(R.id.mail_field);
final EditText passwordEditText = findViewById(R.id.password_field);
final Button login = findViewById(R.id.login);
Inside onCreate just under setContentView(R.layout.activity_sign_in);which the method that inflates the layout.
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