当我按下手机中的后退按钮时，此活动将重新启动，而不是离开应用程序。（这是用户打开应用时显示的活动）
这是代码，它只是一个简单的登录活动，没什么不同。
public class LoginActivity extends AppCompatActivity {
public static final int RC_SIGN_IN = 1;
private GoogleApiClient mGoogleApiClient;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
public static final String TAG = "MAIN_ACTIVITY";
private String email, password;
@BindView(R.id.progressBar)
ProgressBar progressBar;
@BindView(R.id.google_button)
SignInButton mGoogleBtn;
@BindView(R.id.register_button)
TextView mRegisterBtn;
@BindView(R.id.email_edit_text)
EditText mEmail;
@BindView(R.id.password_edit_text)
EditText mPassword;
@BindView(R.id.login_button)
ImageButton mLogin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
ButterKnife.bind(this);
mAuth = FirebaseAuth.getInstance();
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
if (firebaseAuth.getCurrentUser() != null) {
startActivity(new Intent(LoginActivity.this, MainActivity.class));
}
}
};
if (mAuth.getCurrentUser() != null) {
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestIdToken(getString(R.string.default_web_client_id))
.requestEmail()
.build();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this, new GoogleApiClient.OnConnectionFailedListener() {
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
Toast.makeText(LoginActivity.this, R.string.connection_failed, Toast.LENGTH_LONG).show();
}
})
.addApi(Auth.GOOGLE_SIGN_IN_API, gso)
.build();
}
@OnClick(R.id.register_button)
public void register() {
startActivity(new Intent(LoginActivity.this, RegisterActivity.class));
}
@OnClick(R.id.google_button)
public void loginUsingGoogle() {
signIn();
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
}
private void signIn() {
Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
startActivityForResult(signInIntent, RC_SIGN_IN);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
if (requestCode == RC_SIGN_IN) {
GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
if (result.isSuccess()) {
// Google Sign In was successful, authenticate with Firebase
GoogleSignInAccount account = result.getSignInAccount();
firebaseAuthWithGoogle(account);
} else {
// Google Sign In failed, update UI appropriately
// ...
}
}
}
private void firebaseAuthWithGoogle(GoogleSignInAccount account) {
Log.d(TAG, "firebaseAuthWithGoogle:" + account.getId());
AuthCredential credential = GoogleAuthProvider.getCredential(account.getIdToken(), null);
mAuth.signInWithCredential(credential)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());
// If sign in fails, display a message to the user. If sign in succeeds
// the auth state listener will be notified and logic to handle the
// signed in user can be handled in the listener.
if (!task.isSuccessful()) {
Log.w(TAG, "signInWithCredential", task.getException());
Toast.makeText(LoginActivity.this, "Authentication failed.",
Toast.LENGTH_SHORT).show();
}
// ...
}
});
}
@OnClick(R.id.login_button)
public void login() {
email = mEmail.getText().toString();
password = mPassword.getText().toString();
if (TextUtils.isEmpty(email)) {
Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(password)) {
Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
return;
}
progressBar.setVisibility(View.VISIBLE);
//authenticate user
mAuth.signInWithEmailAndPassword(email, password)
.addOnCompleteListener(LoginActivity.this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
// If sign in fails, display a message to the user. If sign in succeeds
// the auth state listener will be notified and logic to handle the
// signed in user can be handled in the listener.
progressBar.setVisibility(View.GONE);
if (!task.isSuccessful()) {
// there was an error
if (password.length() < 6) {
mPassword.setError(getString(R.string.minimum_password));
} else {
Toast.makeText(LoginActivity.this, getString(R.string.auth_failed), Toast.LENGTH_LONG).show();
}
} else {
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
}
});
}
}
我已经尝试过了：
@Override
public void onBackPressed() {
super.onBackPressed();
moveTaskToBack(true);
}
这样：
@Override
public void onBackPressed() {
super.onBackPressed();
finish();
}
和此：
@Override
public void onBackPressed() {
super.onBackPressed();
System.exit(0);
}
这是日志
java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
com.intellij.openapi.extensions.impl.PicoPluginExtensionInitializationException: java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getComponentInstance(ExtensionComponentAdapter.java:96)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getExtension(ExtensionComponentAdapter.java:119)
at com.intellij.openapi.extensions.impl.ExtensionPointImpl.processAdapters(ExtensionPointImpl.java:249)
at com.intellij.openapi.extensions.impl.ExtensionPointImpl.getExtensions(ExtensionPointImpl.java:194)
at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:100)
at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:87)
at com.intellij.openapi.extensions.ExtensionPointName.getExtensions(ExtensionPointName.java:49)
at com.intellij.tasks.TaskRepositoryType.getRepositoryTypes(TaskRepositoryType.java:40)
at com.intellij.tasks.impl.TaskManagerImpl.loadRepositories(TaskManagerImpl.java:618)
at com.intellij.tasks.impl.TaskManagerImpl.loadState(TaskManagerImpl.java:612)
at com.intellij.tasks.impl.TaskManagerImpl.loadState(TaskManagerImpl.java:78)
at com.intellij.configurationStore.ComponentStoreImpl.initPersistentComponent(ComponentStoreImpl.kt:291)
at com.intellij.configurationStore.ComponentStoreImpl.initComponent(ComponentStoreImpl.kt:96)
at com.intellij.openapi.components.impl.PlatformComponentManagerImpl.initializeComponent(PlatformComponentManagerImpl.java:54)
at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentConfigComponentAdapter.getComponentInstance(ComponentManagerImpl.java:520)
at com.intellij.openapi.components.impl.ComponentManagerImpl.createComponents(ComponentManagerImpl.java:123)
at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:107)
at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:90)
at com.intellij.openapi.project.impl.ProjectImpl.init(ProjectImpl.java:282)
at com.intellij.openapi.project.impl.ProjectManagerImpl.initProject(ProjectManagerImpl.java:231)
at com.intellij.openapi.project.impl.ProjectManagerImpl.access$300(ProjectManagerImpl.java:68)
at com.intellij.openapi.project.impl.ProjectManagerImpl$8.compute(ProjectManagerImpl.java:531)
at com.intellij.openapi.project.impl.ProjectManagerImpl$8.compute(ProjectManagerImpl.java:527)
at com.intellij.openapi.progress.impl.CoreProgressManager$4.run(CoreProgressManager.java:198)
at com.intellij.openapi.progress.impl.CoreProgressManager$TaskRunnable.run(CoreProgressManager.java:563)
at com.intellij.openapi.progress.impl.CoreProgressManager$8.run(CoreProgressManager.java:357)
at com.intellij.openapi.progress.impl.CoreProgressManager$2.run(CoreProgressManager.java:142)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:446)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:392)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:54)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:127)
at com.intellij.openapi.application.impl.ApplicationImpl$13$1.run(ApplicationImpl.java:633)
at com.intellij.openapi.application.impl.ApplicationImpl$8.run(ApplicationImpl.java:369)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.loadImplementationClass(ExtensionComponentAdapter.java:160)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getComponentImplementation(ExtensionComponentAdapter.java:66)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getComponentInstance(ExtensionComponentAdapter.java:73)
... 37 more
Caused by: java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:64)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.loadImplementationClass(ExtensionComponentAdapter.java:157)
... 39 more
Caused by:
java.lang.RuntimeException: java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.loadImplementationClass(ExtensionComponentAdapter.java:160)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getComponentImplementation(ExtensionComponentAdapter.java:66)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getComponentInstance(ExtensionComponentAdapter.java:73)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.getExtension(ExtensionComponentAdapter.java:119)
at com.intellij.openapi.extensions.impl.ExtensionPointImpl.processAdapters(ExtensionPointImpl.java:249)
at com.intellij.openapi.extensions.impl.ExtensionPointImpl.getExtensions(ExtensionPointImpl.java:194)
at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:100)
at com.intellij.openapi.extensions.Extensions.getExtensions(Extensions.java:87)
at com.intellij.openapi.extensions.ExtensionPointName.getExtensions(ExtensionPointName.java:49)
at com.intellij.tasks.TaskRepositoryType.getRepositoryTypes(TaskRepositoryType.java:40)
at com.intellij.tasks.impl.TaskManagerImpl.loadRepositories(TaskManagerImpl.java:618)
at com.intellij.tasks.impl.TaskManagerImpl.loadState(TaskManagerImpl.java:612)
at com.intellij.tasks.impl.TaskManagerImpl.loadState(TaskManagerImpl.java:78)
at com.intellij.configurationStore.ComponentStoreImpl.initPersistentComponent(ComponentStoreImpl.kt:291)
at com.intellij.configurationStore.ComponentStoreImpl.initComponent(ComponentStoreImpl.kt:96)
at com.intellij.openapi.components.impl.PlatformComponentManagerImpl.initializeComponent(PlatformComponentManagerImpl.java:54)
at com.intellij.openapi.components.impl.ComponentManagerImpl$ComponentConfigComponentAdapter.getComponentInstance(ComponentManagerImpl.java:520)
at com.intellij.openapi.components.impl.ComponentManagerImpl.createComponents(ComponentManagerImpl.java:123)
at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:107)
at com.intellij.openapi.components.impl.ComponentManagerImpl.init(ComponentManagerImpl.java:90)
at com.intellij.openapi.project.impl.ProjectImpl.init(ProjectImpl.java:282)
at com.intellij.openapi.project.impl.ProjectManagerImpl.initProject(ProjectManagerImpl.java:231)
at com.intellij.openapi.project.impl.ProjectManagerImpl.access$300(ProjectManagerImpl.java:68)
at com.intellij.openapi.project.impl.ProjectManagerImpl$8.compute(ProjectManagerImpl.java:531)
at com.intellij.openapi.project.impl.ProjectManagerImpl$8.compute(ProjectManagerImpl.java:527)
at com.intellij.openapi.progress.impl.CoreProgressManager$4.run(CoreProgressManager.java:198)
at com.intellij.openapi.progress.impl.CoreProgressManager$TaskRunnable.run(CoreProgressManager.java:563)
at com.intellij.openapi.progress.impl.CoreProgressManager$8.run(CoreProgressManager.java:357)
at com.intellij.openapi.progress.impl.CoreProgressManager$2.run(CoreProgressManager.java:142)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:446)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:392)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:54)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:127)
at com.intellij.openapi.application.impl.ApplicationImpl$13$1.run(ApplicationImpl.java:633)
at com.intellij.openapi.application.impl.ApplicationImpl$8.run(ApplicationImpl.java:369)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: org.bitbucket.connectors.jetbrains.tasks.BitbucketIssueRepositoryType PluginClassLoader[org.bitbucket.connector, 1.2.3-SNAPSHOT]
at com.intellij.ide.plugins.cl.PluginClassLoader.loadClass(PluginClassLoader.java:64)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at com.intellij.openapi.extensions.impl.ExtensionComponentAdapter.loadImplementationClass(ExtensionComponentAdapter.java:157)
... 39 more
答案 0 :(得分：2)
我能想到为什么系统会重新启动一个Activity的唯一原因是因为它崩溃了。请检查logcat，并将其添加到问题中。
答案 1 :(得分：1)
尝试从代码中删除onBackPressed()方法并清理项目
答案 2 :(得分：1)
在onBackPressed中添加此意图以关闭应用程序：
Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);