无法从 edittext 获取值到字符串

Question

我正在尝试制作一个 android 应用程序，它会在单击按钮时显示 Toast。该 Toast 包含用户在编辑文本字段中输入的数字。问题是我在 edittext(Numeric) 字段中输入文本，然后单击按钮，Toast 没有显示我输入的文本。吐司是完全空白的。这是我的代码：-

Activity.java

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class login extends AppCompatActivity {

    String username, password;
    Button payNGO, payGO;
    EditText usernameField, passwordField;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        setContentView(R.layout.activity_login);

        payNGO = (Button) findViewById(R.id.payngo);
        payGO = (Button) findViewById(R.id.paygo);

        usernameField = (EditText) findViewById(R.id.forno);
        passwordField = (EditText) findViewById(R.id.dob);

        username = usernameField.getText().toString();
        password = passwordField.getText().toString();


        payNGO.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(login.this, username, Toast.LENGTH_LONG).show();
            }
        });



    }
}

Activity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".login"
    android:background="@drawable/back">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="150dip"
        android:layout_height="150dip"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toTopOf="@+id/forno"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.438"
        app:srcCompat="@drawable/ico" />

    <EditText
        android:id="@+id/forno"
        android:layout_width="match_parent"
        android:layout_height="40dip"
        android:layout_marginBottom="20dp"
        android:layout_marginEnd="30dip"
        android:layout_marginStart="30dip"
        android:background="@drawable/rect_back"
        android:ems="10"
        android:hint="Number"
        android:inputType="number"
        android:paddingEnd="10dp"
        android:paddingStart="10dp"
        app:layout_constraintBottom_toTopOf="@+id/dob"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.562"
        app:layout_constraintStart_toStartOf="parent" />

    <EditText
        android:id="@+id/dob"
        android:layout_width="match_parent"
        android:layout_height="40dip"
        android:layout_marginBottom="124dp"
        android:layout_marginEnd="30dip"
        android:layout_marginStart="30dip"
        android:background="@drawable/rect_back"
        android:ems="10"
        android:hint="Date of Birth"
        android:inputType="numberPassword"
        android:paddingEnd="10dp"
        android:paddingStart="10dp"
        app:layout_constraintBottom_toTopOf="@+id/linearLayout"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.562"
        app:layout_constraintStart_toStartOf="parent" />

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="92dp"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent">

        <Button
            android:id="@+id/payngo"
            android:layout_width="wrap_content"
            android:layout_height="40dip"
            android:layout_marginEnd="20dip"
            android:layout_marginStart="15dip"
            android:layout_weight="1"
            android:background="@drawable/rect_back_button"
            android:text="Pay (NGO)"
            tools:layout_editor_absoluteX="204dp"
            tools:layout_editor_absoluteY="440dp" />

        <Button
            android:id="@+id/paygo"
            android:layout_width="wrap_content"
            android:layout_height="40dip"
            android:layout_marginEnd="15dip"
            android:layout_marginStart="20dip"
            android:layout_weight="1"
            android:background="@drawable/rect_back_button"
            android:text="Pay (GO)"
            tools:layout_editor_absoluteX="92dp"
            tools:layout_editor_absoluteY="440dp" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:background="@drawable/rect_back_text"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent">

        <TextView
            android:id="@+id/textView4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="50dip"
            android:layout_weight="1"
            android:text="@string/linef"
            android:textAlignment="textEnd"
            android:textColor="#fff"
            android:textSize="20sp"
            tools:layout_editor_absoluteX="30dp"
            tools:layout_editor_absoluteY="505dp" />

        <ImageView
            android:id="@+id/imageView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:scaleType="fitCenter"

            app:srcCompat="@drawable/heart"
            tools:ignore="VectorDrawableCompat" />

        <TextView
            android:id="@+id/textView5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="50dip"
            android:layout_weight="1"
            android:text="@string/linee"
            android:textColor="#fff"
            android:textSize="20sp"
            tools:layout_editor_absoluteX="171dp"
            tools:layout_editor_absoluteY="505dp" />
    </LinearLayout>

</android.support.constraint.ConstraintLayout>

Answer 1

由于您正在获取 onCreate 中的值，该值甚至会在您输入任何内容之前执行，因此您的 Toast 显示空白数据。

将 getText() 方法移动到 onClick 以获得如下预期结果：

    payNGO.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            username = usernameField.getText().toString();
            password = passwordField.getText().toString();
            Toast.makeText(login.this, username, Toast.LENGTH_LONG).show();
        }

    });

Answer 2

Toast.makeText(login.this, usernameField.getText().toString(), Toast.LENGTH_LONG).show();

你可以使用这段代码，它绝对有效..

无法从 edittext 获取值到字符串

unable to get value from edittext into string

java

android

gettext

android-edittext

android-toast