我正在尝试制作应用，并希望使用Firebase身份验证来简化操作。我编写了我的代码，我将放在下面，似乎没有明显的错误，但应用程序在启动时崩溃，甚至不让我访问第一个活动
public class MainActivity extends AppCompatActivity {
//all variables and layout elements
private static final String TAG = "EmailPassword";
private FirebaseAuth mAuth;
Button logIn;
Button changeElements;
EditText userName;
EditText passWord;
EditText passWordCheck;
TextView text;
TextView confirmPassword;
String username;
String password;
String passwordCheck;
boolean hasAccount=false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//match variables wwith layout elements
mAuth = FirebaseAuth.getInstance();
logIn = (Button) findViewById(R.id.login);
changeElements = (Button) findViewById(R.id.change_elements);
userName = (EditText) findViewById(R.id.user);
passWord = (EditText) findViewById(R.id.password);
text = (TextView) findViewById(R.id.textView5);
confirmPassword = (TextView) findViewById(R.id.textView3);
//change between login and register
changeElements.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (hasAccount){
hasAccount = false;
confirmPassword.setVisibility(View.VISIBLE);
passWordCheck.setVisibility(View.VISIBLE);
logIn.setText("Register");
changeElements.setText("Log In");
text.setText("Already have an account?");
}else{
hasAccount = true;
confirmPassword.setVisibility(View.INVISIBLE);
passWordCheck.setVisibility(View.INVISIBLE);
logIn.setText("Log In");
changeElements.setText("Register");
text.setText("Don't have an account? Register here");
}
}
});
//if log-in or register button is clicked
logIn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
username = userName.toString();
password = passWord.toString();
//to login,
if (hasAccount){
signIn(username, password);
}else{
if(password!= null && !password.isEmpty()&& username!= null && !username.isEmpty() && password==passwordCheck){
//if password and username fields are not empty and the confirmed password matches, create account
userAuth(username,password);
}else if(password!=passwordCheck){
passWordCheck.setError("Passwords do not match");
}else if(username.isEmpty()||username == null){
userName.setError("Please enter username");
}
else if(password.isEmpty()||password == null){
passWord.setError("Please enter password");
}
}
}
});
}
@Override
protected void onStart() {
super.onStart();
//Check to see if user is signed in, this is firebase code
FirebaseUser currentUser = mAuth.getCurrentUser();
updateUi(currentUser);
}
public void updateUi (FirebaseUser user){
if(user!=null){
//if user, go to next activity
Intent intent = new Intent(this, Parties.class);
startActivity(intent);
}else{
//if no user, stay on page, clear fields and display error message
userName.setError("Something went wrong. Please try again");
userName.setText("");
passWord.setText("");
passWordCheck.setText("");
}
}
//just put the firebase create user code in a method
public void userAuth(String username, String password){
mAuth.createUserWithEmailAndPassword(username,password).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()){
Log.d(TAG, "createUserWithEmailSucces");
FirebaseUser user = mAuth.getCurrentUser();
updateUi(user);
}
else {
Log.w(TAG,"createUserWithEmailFailure");
Toast.makeText(MainActivity.this, "Authentification failed", Toast.LENGTH_SHORT).show();
updateUi(null);
}
}
});
}
//same thing here for the sign in
public void signIn(String username,String password){
mAuth.signInWithEmailAndPassword(username, 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, "signInWithEmail:success");
FirebaseUser user = mAuth.getCurrentUser();
updateUi(user);
} else {
// If sign in fails, display a message to the user.
Log.w(TAG, "signInWithEmail:failure", task.getException());
Toast.makeText(MainActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
updateUi(null);
}
}
});
}
}
这是我的logcat
**
06-13 17:45:45.864 2366-2366/? I/art: Not late-enabling -Xcheck:jni (already on)
06-13 17:45:45.864 2366-2366/? W/art: Unexpected CPU variant for X86 using defaults: x86
06-13 17:45:45.970 2366-2366/com.example.eliott.proto_onrop W/System: ClassLoader referenced unknown path: /data/app/com.example.eliott.proto_onrop-2/lib/x86
06-13 17:45:46.037 2366-2366/com.example.eliott.proto_onrop D/FirebaseApp: com.google.firebase.crash.FirebaseCrash is not linked. Skipping initialization.
06-13 17:45:46.056 2366-2388/com.example.eliott.proto_onrop W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
06-13 17:45:46.063 2366-2366/com.example.eliott.proto_onrop I/FA: App measurement is starting up, version: 11010
06-13 17:45:46.063 2366-2366/com.example.eliott.proto_onrop I/FA: To enable debug logging run: adb shell setprop log.tag.FA VERBOSE
06-13 17:45:46.064 2366-2388/com.example.eliott.proto_onrop W/GooglePlayServicesUtil: Google Play services out of date. Requires 11010000 but found 10298470
06-13 17:45:46.073 2366-2366/com.example.eliott.proto_onrop V/FA: Collection enabled
06-13 17:45:46.073 2366-2366/com.example.eliott.proto_onrop V/FA: App package, google app id: com.example.eliott.proto_onrop, 1:95710228681:android:5771a0cac4b901a2
06-13 17:45:46.074 2366-2366/com.example.eliott.proto_onrop I/FA: To enable faster debug mode event logging run:
adb shell setprop debug.firebase.analytics.app com.example.eliott.proto_onrop
06-13 17:45:46.074 2366-2366/com.example.eliott.proto_onrop D/FA: Debug-level message logging enabled
06-13 17:45:46.095 2366-2366/com.example.eliott.proto_onrop V/FA: Cancelling job. JobID: 653780905
06-13 17:45:46.101 2366-2366/com.example.eliott.proto_onrop V/FA: Registered activity lifecycle callback
06-13 17:45:46.102 2366-2366/com.example.eliott.proto_onrop I/FirebaseInitProvider: FirebaseApp initialization successful
06-13 17:45:46.102 2366-2366/com.example.eliott.proto_onrop I/InstantRun: starting instant run server: is main process
06-13 17:45:46.106 2366-2393/com.example.eliott.proto_onrop V/FA: Using measurement service
06-13 17:45:46.107 2366-2393/com.example.eliott.proto_onrop V/FA: Connecting to remote service
06-13 17:45:46.107 2366-2393/com.example.eliott.proto_onrop W/GooglePlayServicesUtil: Google Play services out of date. Requires 11010000 but found 10298470
06-13 17:45:46.108 2366-2393/com.example.eliott.proto_onrop V/FA: Using measurement service
06-13 17:45:46.108 2366-2393/com.example.eliott.proto_onrop V/FA: Connection attempt already in progress
06-13 17:45:46.184 2366-2366/com.example.eliott.proto_onrop W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
06-13 17:45:46.189 2366-2366/com.example.eliott.proto_onrop V/FA: onActivityCreated
06-13 17:45:46.248 2366-2366/com.example.eliott.proto_onrop D/AndroidRuntime: Shutting down VM
--------- beginning of crash
06-13 17:45:46.248 2366-2366/com.example.eliott.proto_onrop E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.eliott.proto_onrop, PID: 2366
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.eliott.proto_onrop/com.example.eliott.proto_onrop.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(java.lang.CharSequence)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.EditText.setText(java.lang.CharSequence)' on a null object reference
at com.example.eliott.proto_onrop.MainActivity.updateUi(MainActivity.java:151)
at com.example.eliott.proto_onrop.MainActivity.onStart(MainActivity.java:130)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1248)
at android.app.Activity.performStart(Activity.java:6679)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2609)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
**
这些是我的build.gradle文件，即项目
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.3.3'
classpath 'com.google.gms:google-services:3.1.0'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
和模块
apply plugin: 'com.android.application'
android {
compileSdkVersion 25
buildToolsVersion "25.0.3"
defaultConfig {
applicationId "com.example.eliott.proto_onrop"
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:25.3.1'
testCompile 'junit:junit:4.12'
compile 'com.google.firebase:firebase-database:11.0.0'
compile 'com.google.firebase:firebase-core:11.0.0'
compile 'com.google.firebase:firebase-auth:11.0.0'
}
apply plugin: 'com.google.gms.google-services'
答案 0 :(得分：0)
由于空指针异常!!!此强制关闭!!!
在MainActivity中 - 检查登录按钮的OnClickListener
}else if(password!=passwordCheck){
passWordCheck.setError（＆＃34;密码不匹配＆＃34;）;
}else if(username.isEmpty()||username == null){
您是否在OnCreate中引用了 EditText passWordCheck 的ID？