为什么我想先放映的activity没有放映

Question

我不确定该如何表述这个问题，但我目前面临的问题是，为什么我的LoginActivity在启动时没有显示。下面是我的代码

 <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_login"
            android:theme="@style/Theme.TutorSeekers30.NoActionBar" ></activity>
        <activity
            android:name=".ForgetAccount"
            android:label="@string/title_activity_forget_account"
            android:theme="@style/Theme.TutorSeekers30.NoActionBar"></activity>
        <activity
            android:name=".SignupActivity"
            android:label="@string/title_activity_signup"
            android:theme="@style/Theme.TutorSeekers30.NoActionBar" ></activity>

        <activity android:name=".LoginActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

因此，为了让您想要的activity首先显示，您必须替换您想要的 右侧上方的那个？但替换后，不知何故我的loginActivity并不是显示的第一个屏幕。我尝试将忘记帐户和signupActivity替换为启动时显示的第一个屏幕，并且两者都按预期显示。然而，对于我的LoginActivity，它并不显示为第一个屏幕预期。为什么？我还需要在这里展示其他东西吗？

下面是我的LoginActivity：

public class LoginActivity extends AppCompatActivity {
    EditText etUsername,etPassword;
    Button btnLogin;
    TextView tvForgetAccount,tvCreateAccount;
    ProgressBar pbBar;
    private FirebaseAuth auth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        auth = FirebaseAuth.getInstance();
        if (auth.getCurrentUser() != null){
            startActivity(new Intent(LoginActivity.this,MainActivity.class));
            finish();
        }

        etPassword = findViewById(R.id.etPassword);
        etUsername = findViewById(R.id.etUsername);
        btnLogin = findViewById(R.id.Loginbutton);
        tvCreateAccount = findViewById(R.id.tvCreateAccount);
        tvForgetAccount = findViewById(R.id.tvForgetAccount);
        pbBar = findViewById(R.id.progressBar2);

        tvCreateAccount.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(LoginActivity.this,SignupActivity.class);
                startActivity(i);
            }
        });
        tvForgetAccount.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(LoginActivity.this,ForgetAccount.class);
                startActivity(i);
            }
        });

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = etUsername.getText().toString();
                final String password = etPassword.getText().toString();

                if (TextUtils.isEmpty(username)){
                    Toast.makeText(getApplicationContext(),"Please enter your username",Toast.LENGTH_SHORT).show();
                    return;
                }

                if (TextUtils.isEmpty(password)){
                    Toast.makeText(getApplicationContext(),"Please enter your password",Toast.LENGTH_SHORT).show();
                    return;
                }
                pbBar.setVisibility(View.VISIBLE);
                auth.signInWithEmailAndPassword(username,password).addOnCompleteListener(LoginActivity.this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        pbBar.setVisibility(View.GONE);
                        if (!task.isSuccessful()){
                            if (password.length() < 6 ){
                                Toast.makeText(getApplicationContext(),"Wrong Password. Please try again",Toast.LENGTH_LONG).show();
                                return;
                            }else if (password.isEmpty()){
                                Toast.makeText(getApplicationContext(),"Password field cannot be empty",Toast.LENGTH_SHORT).show();
                                return;
                            }
                        } else{
                            Intent i = new Intent(LoginActivity.this,MainActivity.class);
                            startActivity(i);
                            finish();
                            }
                        }
                    });
                }

            });
        };


    }

以下是我的SignupActivity：

public class SignupActivity extends AppCompatActivity {
    private FirebaseAuth mAuth;
    EditText etName,etPassword,etPhone,etEmail;
    Button btnCreate;
    private ProgressBar progressbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signup);

        mAuth = FirebaseAuth.getInstance();
        
        etName = findViewById(R.id.editTextTextPersonName);
        etPassword = findViewById(R.id.editTextTextPassword);
        etPhone = findViewById(R.id.editTextPhone);
        etEmail = findViewById(R.id.editTextTextEmailAddress);
        btnCreate = findViewById(R.id.CreateButton);
        progressbar = findViewById(R.id.progressBar);
        
        btnCreate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                registerNewUser();
            }
        });


    }

    private void registerNewUser() {
        progressbar.setVisibility(View.VISIBLE);
        String email,password,username;
        int ContactNumber ;
        email = etEmail.getText().toString();
        password = etPassword.getText().toString();
        username = etName.getText().toString();
        PhoneNumberUtils.formatNumber(etPhone.getText().toString());

        if (TextUtils.isEmpty(email)){
            Toast.makeText(getApplicationContext(),"Please Enter Email!",Toast.LENGTH_LONG).show();
            return;
        }

        if (TextUtils.isEmpty(password)){
            Toast.makeText(getApplicationContext(),"Please Enter Password!",Toast.LENGTH_LONG).show();
            return;
        }

        if (TextUtils.isEmpty(username)){
            Toast.makeText(getApplicationContext(),"Please Enter Username!",Toast.LENGTH_LONG).show();
            return;
        }

        if (password.length() < 6){
            Toast.makeText(getApplicationContext(),"Password too short , Please enter a minimum value of 6 characters",Toast.LENGTH_LONG).show();
            return;
        }

        mAuth.createUserWithEmailAndPassword(email,password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                if (task.isSuccessful()){
                    Toast.makeText(getApplicationContext(),"Registration is Successful!",Toast.LENGTH_LONG).show();
                    progressbar.setVisibility(View.GONE);
                    Intent intent = new Intent(SignupActivity.this,MainActivity.class);
                    startActivity(intent);
                }
                else{
                    Toast.makeText(getApplicationContext(),"Registration failed! " + " Please try Again ",Toast.LENGTH_LONG).show();
                    startActivity(new Intent(SignupActivity.this,MainActivity.class));
                    progressbar.setVisibility(View.GONE);
                    finish();
                }
            }
        });


    }
}

这是我的遗忘账户

public class ForgetAccount extends AppCompatActivity {
    EditText etUsername,etEmail;
    Button btnSend;
    private ProgressBar progressBar;
    FirebaseAuth auth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_forget_account);

        etEmail = findViewById(R.id.editTextTextEmailAddress2);
        etUsername = findViewById(R.id.etUsername);
        btnSend = findViewById(R.id.Sendbutton);
        progressBar = findViewById(R.id.progressBar2);

        auth = FirebaseAuth.getInstance();
        btnSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String email = etEmail.getText().toString().trim();
                String username = etUsername.getText().toString();

                if (TextUtils.isEmpty(email)){
                    Toast.makeText(getApplication(), "Enter your registered email id", Toast.LENGTH_SHORT).show();
                    return;
                }
                if (TextUtils.isEmpty(username)){
                    Toast.makeText(getApplication(), "Enter your Username", Toast.LENGTH_SHORT).show();
                    return;
                }
                progressBar.setVisibility(View.VISIBLE);
                auth.sendPasswordResetEmail(email).addOnCompleteListener(new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                        if (task.isSuccessful()){
                            Toast.makeText(ForgetAccount.this,"We have sent instructions to your registered email",Toast.LENGTH_SHORT).show();
                        }else{
                            Toast.makeText(ForgetAccount.this,"Failed to send email!",Toast.LENGTH_SHORT).show();
                        }
                        progressBar.setVisibility(View.GONE);
                    }
                });
            }
        });

    }
}

Answer 1

在每个activity中添加相同的主题属性是多余和无用的。为了使其全局可用，在application标记中声明了Theme属性。其余的清单文件应该如下所示。

       <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.TutorSeekers30.NoActionBar">

        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_login" />
        <activity
            android:name=".ForgetAccount"
            android:label="@string/title_activity_forget_account"/>
        <activity
            android:name=".SignupActivity"
            android:label="@string/title_activity_signup"/>

        <activity android:name=".LoginActivity">
            <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
       </activity>