引起：java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法“TextInputLayout.getEditText()”

问题描述

我正在尝试验证我的登录信息，但每次按下登录按钮时都会出现“应用程序不断停止”错误。

在我的 activity_login.xml 中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"
    android:background="@color/login_bk_color"
    android:focusableInTouchMode="true"
    android:gravity="center"
    tools:context=".LoginActivity">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_centerInParent="true"
        android:paddingTop="20dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:padding="20dp"
            android:gravity="center"
            >

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="15dp"
                    android:layout_marginBottom="40dp"
                    android:src="@drawable/logo"/>
   <LinearLayout
       android:layout_width="match_parent"
       android:layout_height="wrap_content">
       <TextView
           style="@style/viewParent.headerText.NoMode"
           android:text="Inicie Sessão"
           android:layout_marginBottom="20dp"/>
   </LinearLayout>
            <com.google.android.material.textfield.TextInputLayout
                android:id="@+id/textInputEmail"
                style="@style/parent"
                android:layout_marginTop="@dimen/loginViewsMargin">

                <EditText
                    android:id="@+id/textEmail"
                    style="@style/modifiedEditText"
                    android:drawableStart="@drawable/ic_baseline_email_24"
                    android:hint="@string/login_email_hint"
                    android:inputType="textEmailAddress"
                    android:maxLines="1"
                    android:textSize="18sp" />
            </com.google.android.material.textfield.TextInputLayout>

            <com.google.android.material.textfield.TextInputLayout
                android:id="@+id/textInputLoginPassword"
                style="@style/parent"
                android:layout_marginTop="@dimen/loginViewsMargin"
                app:endIconMode="password_toggle"
                >

                <EditText
                    android:id="@+id/password"
                    style="@style/modifiedEditText"
                    android:hint="@string/login_password_hint"
                    android:inputType="textPassword"
                    android:maxLines="1"
                    android:textSize="18sp"
                    android:drawableStart="@drawable/ic_baseline_lock_24"/>

                <TextView
                    style="@style/viewParent"
                    android:layout_gravity="end"

                    android:text="Forgot Password?"
                    android:textColor="@color/primaryTextColor"
                    android:textSize="@dimen/newsMoreTextSize" />
            </com.google.android.material.textfield.TextInputLayout>

            <br.com.simplepass.loading_button_lib.customViews.CircularProgressButton
                android:id="@+id/cirLoginButton"
                style="@style/loginButton"
                android:onClick="loginUser"
                android:layout_gravity="center_horizontal"
                android:layout_marginTop="15dp"
                android:text="Login"
                app:initialCornerAngle="27dp"
                app:spinning_bar_color="#FFF"
                app:spinning_bar_padding="6dp"
                app:spinning_bar_width="4dp" />

            <TextView
                style="@style/parent"
                android:layout_marginTop="@dimen/loginViewsMargin"
                android:onClick="onLoginClick"
                android:text="New user? Register Now"
                android:textAlignment="center"
                android:textColor="@color/themeColor"
                android:textSize="17sp"
                android:textStyle="bold" />


            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="30dp"
                android:gravity="center"
                android:weightSum="12">

                <View
                    android:layout_width="0dp"
                    android:layout_height="1dp"
                    android:layout_weight="3"
                    android:background="@color/colorPrimaryDark" />

                <TextView
                    style="@style/viewParent.headerText.NoMode"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="6"
                    android:text="Use other Methods"
                    android:textAlignment="center"
                    android:textSize="12sp" />

                <View
                    android:layout_width="0dp"
                    android:layout_height="1dp"
                    android:layout_weight="3"
                    android:background="@color/colorPrimaryDark" />

            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="20dp"
                android:gravity="center">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:src="@drawable/ic_facebook" />

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="10dp"
                    android:src="@drawable/ic_google_plus" />
            </LinearLayout>

        </LinearLayout>
    </ScrollView>

    <View
        android:layout_width="11dp"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="20dp"
        android:background="@drawable/ic_side_bg" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_marginRight="11dp"
        android:layout_marginBottom="30dp"
        android:onClick="onLoginClick"
        android:src="@drawable/ic_add_img" />

</RelativeLayout>

在我的 LoginActivity.java 中

package com.example.papbiensaude;

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.textfield.TextInputLayout;
import com.google.firebase.auth.FirebaseAuth;

public class LoginActivity extends AppCompatActivity {

    private TextInputLayout textInputPassword;
     FirebaseAuth firebaseAuth;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        textInputPassword = findViewById(R.id.textInputLoginPassword);

        firebaseAuth = FirebaseAuth.getInstance();


        //for changing status bar icon colors
        if(Build.VERSION.SDK_INT>= Build.VERSION_CODES.M){
            getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
        }
        setContentView(R.layout.activity_login);

    }
    public void onLoginClick(View View){
        startActivity(new Intent(this,RegisterActivity.class));
        overridePendingTransition(R.anim.slide_in_right,R.anim.stay);
    }

      @Override
    protected void onStart() {
        super.onStart();
        if(FirebaseAuth.getInstance().getCurrentUser() != null){
            startActivity(new Intent(getApplicationContext(),MainActivity.class));
            finish();
        }
    }

    private boolean validatePassword(){
        String val = textInputPassword.getEditText().getText().toString().trim();
        String passwordVal = ( "^" +
                "(?=.*[0-9])"+
                "(?=.*[A-Z])"+
                "(?=.*[a-z])"+
                "(?=.*[@#$._%^&+=])"+
                ".{8,}"+
                "$");

        if (val.isEmpty()){
            textInputPassword.setError("required field");
            return false;
        } else if (!val.matches(passwordVal)){
            textInputPassword.setError("The password is very weak");
            return false;
        }
        else {
            textInputPassword.setError(null);
            return true;
        }
    }

    public void loginUser(View view){

        if(!validatePassword() ){
            return;
        }


        Toast.makeText(LoginActivity.this,"Valid",Toast.LENGTH_SHORT).show();
    }
}

当我删除我的点击 (loginUser) 时，应用程序再次正常工作。 如果我单击登录按钮，logcat 中将出现以下内容

  Process: com.example.papbiensaude,PID: 17251
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at android.view.View$DeclaredOnClickListener.onClick(View.java:5634)
        at android.view.View.performClick(View.java:6597)
        at android.view.View.performClickInternal(View.java:6574)
        at android.view.View.access$3100(View.java:778)
        at android.view.View$PerformClick.run(View.java:25885)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at android.view.View$DeclaredOnClickListener.onClick(View.java:5629)
        at android.view.View.performClick(View.java:6597) 
        at android.view.View.performClickInternal(View.java:6574) 
        at android.view.View.access$3100(View.java:778) 
        at android.view.View$PerformClick.run(View.java:25885) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.widget.EditText com.google.android.material.textfield.TextInputLayout.getEditText()' on a null object reference
        at com.example.papbiensaude.LoginActivity.validatePassword(LoginActivity.java:50)
        at com.example.papbiensaude.LoginActivity.loginUser(LoginActivity.java:74)
        at java.lang.reflect.Method.invoke(Native Method) 
        at android.view.View$DeclaredOnClickListener.onClick(View.java:5629) 
        at android.view.View.performClick(View.java:6597) 
        at android.view.View.performClickInternal(View.java:6574) 
        at android.view.View.access$3100(View.java:778) 
        at android.view.View$PerformClick.run(View.java:25885) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 

我仍然不明白错误在哪里以及如何恢复它！！

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

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