Android - 我不能 go 到下一个活动

Question

这是我的日志猫。 我尝试了这么多天，但无法解决错误。

com.example.project E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.project, PID: 5761
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:402)
        at android.view.View.performClick(View.java:4780)
        at android.view.View$PerformClick.run(View.java:19866)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5305)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397)
        at android.view.View.performClick(View.java:4780) 
        at android.view.View$PerformClick.run(View.java:19866) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:135) 
        at android.app.ActivityThread.main(ActivityThread.java:5305) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:372) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.widget.EditText com.google.android.material.textfield.TextInputLayout.getEditText()' on a null object reference
        at com.example.project.SignUp.validateFullName(SignUp.java:110)
        at com.example.project.SignUp.call2ndSignUpScreen(SignUp.java:50)
        at java.lang.reflect.Method.invoke(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:372) 
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397) 
        at android.view.View.performClick(View.java:4780) 
        at android.view.View$PerformClick.run(View.java:19866) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:135) 
        at android.app.ActivityThread.main(ActivityThread.java:5305) 
        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:903) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

这是我的注册活动。 从这个活动我想转移到第二个注册活动。 其代码在注册 CLASS 代码下方给出。

package com.example.project;

import android.app.ActivityOptions;
import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Pair;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.textfield.TextInputLayout;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;


public class SignUp extends AppCompatActivity {
    ImageView backBtn;
    Button next, login;
    TextView titleText;
    TextInputLayout fullname, username, email, password;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_sign_up);


        backBtn = (ImageView) findViewById(R.id.singup_back_btn);
        next = (Button) findViewById(R.id.singup_next_btn);
        login = (Button) findViewById(R.id.singup_login_btn);
        titleText = (TextView) findViewById(R.id.signup_title_text);


    fullname = (TextInputLayout) findViewById(R.id.signup_fullname);
    username = (TextInputLayout) findViewById(R.id.signup_username);
    email = (TextInputLayout) findViewById(R.id.signup_email);
    password = (TextInputLayout) findViewById(R.id.signup_password);


    }

    public void call2ndSignUpScreen(View view) {

        if (!validateFullName() | !validateUserName() | !validateEmail() | !validatePassword()) {
            return;
        }


        String fullName =fullname.getEditText().getText().toString();
        String userName =username.getEditText().getText().toString();
        String Email =email.getEditText().getText().toString();
        String Password =password.getEditText().getText().toString();
        UserHelperClass helperclass = new UserHelperClass();

        FirebaseDatabase database = FirebaseDatabase.getInstance();
        DatabaseReference myRef = database.getReference("Users");

        myRef.setValue(helperclass);

        Intent intent = new Intent(getApplicationContext(), SignUp2ndClass.class);

        intent.putExtra("fullname", fullName);
        intent.putExtra("username", userName);
        intent.putExtra("email", Email);
        intent.putExtra("password", Password);


        Pair[] pairs = new Pair[4];
        pairs[0] = new Pair<View, String>(next, "transition_back_btn");
        pairs[1] = new Pair<View, String>(next, "transition_title_text");
        pairs[2] = new Pair<View, String>(next, "transition_next_btn");
        pairs[3] = new Pair<View, String>(next, "transition_login_btn");


        ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(SignUp.this, pairs);
        startActivity(intent, options.toBundle());
    }


    public void callstartupscreen(View view) {

        Intent intent = new Intent(getApplicationContext(), StartUpScreen.class);

        Pair[] pairs = new Pair[1];
        pairs[0] = new Pair<View, String>(findViewById(R.id.singup_back_btn), "signup_transition_back_btn");

        ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(SignUp.this, pairs);
        startActivity(intent, options.toBundle());
    }

    public void callLoginScreen(View view) {

        Intent intent = new Intent(getApplicationContext(), LogIn.class);

        Pair[] pairs = new Pair[1];
        pairs[0] = new Pair<View, String>(findViewById(R.id.singup_login_btn), "transition_login_btn");

        ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(SignUp.this, pairs);
        startActivity(intent, options.toBundle());
    }

    private boolean validateFullName() {

        String val = fullname.getEditText().getText().toString().trim();

        if (val.isEmpty()) {
            fullname.setError("Field can not be Empty");
            return false;
        } else {
            fullname.setError(null);
            fullname.setErrorEnabled(false);
            return true;
        }
    }

    private boolean validateUserName() {

        String val = username.getEditText().getText().toString().trim();
        String checkspaces = "\\A\\w{1,20}\\z";

        if (val.isEmpty()) {
            username.setError("Field can not be Empty");
            return false;
        } else if (val.length() > 20) {
            username.setError("Username is too large");
            return false;
        } else if (!val.matches(checkspaces)) {
            username.setError("No white spaces are allowed!");
            return false;
        } else {
            username.setError(null);
            username.setErrorEnabled(false);
            return true;
        }
    }

    private boolean validateEmail() {

        String val = email.getEditText().getText().toString().trim();
        String checkEmail = "[a-zA-Z0-9._-]+@[a-z]+\\.+[a-z]+";

        if (val.isEmpty()) {
            email.setError("Field can not be Empty");
            return false;
        } else if (!val.matches(checkEmail)) {
            email.setError("Invalid Email!");
            return false;
        } else {
            email.setError(null);
            email.setErrorEnabled(false);
            return true;
        }
    }

    private boolean validatePassword() {

        String val = password.getEditText().getText().toString().trim();
        String checkPassword = "^" +
                "(?=.*[a-zA-Z])" +
                "(?=.*[@#$%^&+=])" +
                ".{4,}" +
                "$";

        if (val.isEmpty()) {
            password.setError("Field can not be Empty");
            return false;
        } else if (!val.matches(checkPassword)) {
            password.setError("Password is weak Try another one!");
            return false;
        } else {
            password.setError(null);
            password.setErrorEnabled(false);
            return true;
        }
    }


}

This is my 2nd signup activity.I cannot move to this actvity by clicking on the button which has an onclick function in its xml file.All the other buttons are working which i added in my whole project.i have 3 in total signup activities after我在上次注册活动中单击下一步按钮，数据将保存在 firebase 中。 但不幸的是，我无法从我的第一次注册活动中继续前进。

package com.example.project;

import android.app.ActivityOptions;
import android.content.Intent;
import android.os.Bundle;
import android.util.Pair;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class SignUp2ndClass extends AppCompatActivity {


    ImageView backBtn;
    Button next, login;
    TextView titleText;

    RadioGroup radioGroup;
    RadioButton selectGender;
    DatePicker datePicker;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_sign_up2nd_class);



        backBtn = findViewById(R.id.singup2_back_button);
        next = findViewById(R.id.singup2_next_button);
        login = findViewById(R.id.singup2_login_btn);
        titleText = findViewById(R.id.signup2_title_text);
        radioGroup = findViewById(R.id.radio_group);
        datePicker = findViewById(R.id.age_picker);

    }


    public void call3rdSignUpScreen(View view) {

        if(!validateGender()){
            return;
        }

        selectGender =findViewById(radioGroup.getCheckedRadioButtonId());
        String _gender = selectGender.getText().toString();
        int day = datePicker.getDayOfMonth();
        int month = datePicker.getMonth();
        int year = datePicker.getYear();

        String _date = day+"/"+month+"/"+year;
        String fullname = getIntent().getStringExtra("fullname");
        String username = getIntent().getStringExtra("username");
        String email = getIntent().getStringExtra("email");
        String password = getIntent().getStringExtra("password");

        Intent intent = new Intent(getApplicationContext(), SignUp3rdClass.class);

        Pair[] pairs = new Pair[4];
        pairs[0] = new Pair<View, String>(next, "transition_back_btn");
        pairs[1] = new Pair<View, String>(next, "transition_title_text");
        pairs[2] = new Pair<View, String>(next, "transition_next_btn");
        pairs[3] = new Pair<View, String>(next, "transition_login_btn");


        ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(SignUp2ndClass.this, pairs);
        startActivity(intent, options.toBundle());
    }


    private boolean validateGender(){

        if(radioGroup.getCheckedRadioButtonId()==-1){
            Toast.makeText(this, "Please Select Gender", Toast.LENGTH_SHORT).show();
            return false;
        }else{
            return true;
        }
    }

    public void callLoginScreen (View view){

        Intent intent = new Intent(getApplicationContext(),LogIn.class);

        Pair[] pairs = new Pair[1];
        pairs[0] = new Pair<View, String>(findViewById(R.id.singup2_login_btn),"transition_login_btn");

        ActivityOptions options=ActivityOptions.makeSceneTransitionAnimation(SignUp2ndClass.this,pairs);
        startActivity(intent,options.toBundle());
    }

}

Answer 1

您尚未在 SignUp 活动中初始化任何 TextInputLayout 全名、用户名、email 和密码。