在 android 工作室中计算 Java

Question

我已经创建了几个用户可以输入数字的 EditText，我想在最后一个名为 math_test2.Can 的 Edittext 中获取并显示输出，你们帮我看看语法？我是 android studio 的新手，我不知道完成这项工作的语法。我想我需要存储 x 和 y 的数字输入以及另一个变量 z，然后设置 z = 输出。然后从我创建的常规 java 文件中获取方法。我知道我应该创建一个实例，但我不确定我是否知道该怎么做 correctly.I 我正在努力更好地使用 android studio。我使 MainActivity 依赖于位于我创建的新模块中的 JavaMathExample1 文件。谢谢！

**activity_main.xml file:**

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".MainActivity">

    <TextView
        android:layout_width="166dp"
        android:layout_height="70dp"
        android:gravity="center"
        android:text="Math Test Demo"
        android:textAlignment="center"
        android:textSize="20sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.044"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.167" />


    <EditText
        android:id="@+id/calculateX"
        android:layout_width="251dp"
        android:layout_height="62dp"
        android:hint="Enter x value:"
        android:padding="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.071"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.316" />


    <EditText
        android:id="@+id/calculateY"
        android:layout_width="265dp"
        android:layout_height="58dp"
        android:hint="Enter y value:"
        android:padding="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.078"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.456" />


    <EditText
        android:id="@+id/math_test2"
        android:layout_width="324dp"
        android:layout_height="68dp"
        android:hint="Calculated Output for x and y: "
        android:padding="15dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.126"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.598" />

</androidx.constraintlayout.widget.ConstraintLayout>


**MainActivity.java file:**

package com.example.testdemo;



import com.example.javaprogram.JavaMathExample1;

public class MainActivity extends AppCompatActivity {

    EditText calculateX,calculateY,output;
    JavaMathExample1 javaMathExample1;

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

        calculateX = (EditText) findViewById(R.id.calculateX);
        calculateY = (EditText) findViewById(R.id.calculateY);
        output = (EditText) findViewById(R.id.math_test2);


        String x = calculateX.getText().toString();// Enter a number for x
        String y  = calculateY.getText().toString();// Enter a number for y
        String result = output.getText().toString();// Get output from method created in JavaMathExample1

        calculateY.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

        calculateY.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

        output.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            
            JavaMathExample1 myObj = new JavaMathExample1();
            myObj.fullThrottle(x,y);

            }
        }); 
    }
}



**Regular Java file from "New Module android library created"**

package com.example.javaprogram

public class JavaMathExample1 {

    public void fullThrottle(double x, double y) {

        // return the maximum of two numbers
        System.out.println("Maximum number of x and y is: " + Math.max(x, y));
    }
}

Answer 1

为了计算输入的 x 和 y，我对您在上面发布的所有三个类进行了更改。

xml布局：

<?xml version="1.0" encoding="utf-8">
  <androidx.constraintlayout.widget.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">

<TextView
  android:layout_width="166dp"
  android:layout_height="70dp"
  android:gravity="center"
  android:text="Math Test Demo"
  android:textAlignment="center"
  android:textSize="20sp"
  android:textStyle="bold"
  app:layout_constraintBottom_toBottomOf="parent"
  app:layout_constraintHorizontal_bias="0.044"
  app:layout_constraintLeft_toLeftOf="parent"
  app:layout_constraintRight_toRightOf="parent"
  app:layout_constraintTop_toTopOf="parent"
  app:layout_constraintVertical_bias="0.167" />

<EditText
  android:id="@+id/calculateX"
  android:layout_width="251dp"
  android:layout_height="62dp"
  android:hint="Enter x value:"
  android:padding="15dp"
  app:layout_constraintBottom_toBottomOf="parent"
  app:layout_constraintEnd_toEndOf="parent"
  app:layout_constraintHorizontal_bias="0.071"
  app:layout_constraintStart_toStartOf="parent"
  app:layout_constraintTop_toTopOf="parent"
  app:layout_constraintVertical_bias="0.316" />


<EditText
  android:id="@+id/calculateY"
  android:layout_width="265dp"
  android:layout_height="58dp"
  android:hint="Enter y value:"
  android:padding="15dp"
  app:layout_constraintBottom_toBottomOf="parent"
  app:layout_constraintEnd_toEndOf="parent"
  app:layout_constraintHorizontal_bias="0.078"
  app:layout_constraintStart_toStartOf="parent"
  app:layout_constraintTop_toTopOf="parent"
  app:layout_constraintVertical_bias="0.456" />

<EditText
  android:id="@+id/math_test2"
  android:layout_width="324dp"
  android:layout_height="68dp"
  android:hint="Calculated Output for x and y: "
  android:padding="15dp"
  app:layout_constraintBottom_toBottomOf="parent"
  app:layout_constraintEnd_toEndOf="parent"
  app:layout_constraintHorizontal_bias="0.126"
  app:layout_constraintStart_toStartOf="parent"
  app:layout_constraintTop_toTopOf="parent"
  app:layout_constraintVertical_bias="0.598" />

<Button
  android:id="@+id/calculate"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:text="Calculate"
  app:layout_constraintTop_toBottomOf="@id/math_test2"
  app:layout_constraintStart_toStartOf="parent"
  app:layout_constraintEnd_toEndOf="parent"/>

 </androidx.constraintlayout.widget.ConstraintLayout>

主要活动：

public class MainActivity extends AppCompatActivity {

EditText calculateX, calculateY, output;

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

    calculateX = findViewById(R.id.calculateX);
    calculateY = findViewById(R.id.calculateY);
    output = findViewById(R.id.math_test2);

    findViewById(R.id.calculate).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            JavaMathExample1 myObj = new JavaMathExample1();
            String inputX = calculateX.getText().toString();
            String inputY = calculateY.getText().toString();

            if (inputX.isEmpty() || inputY.isEmpty()) {
                Toast.makeText(MainActivity.this, "Enter X or Y value", Toast.LENGTH_LONG).show();
            } else {
                double x = Double.parseDouble(inputX);  // Enter a number for x
                double y = Double.parseDouble(inputY); // Enter a number for y
                double max = myObj.fullThrottle(x, y); //This will give you result
                output.setText(String.format("%s", max));
            }
        }
    });
}
}

JavaMathExample1:

public class JavaMathExample1 {
public double fullThrottle(double x, double y) {
    double max = Math.max(x, y);
    // return the maximum of two numbers
    System.out.println("Maximum number of x and y is: " + max);
    return max;
}
}

如果您仍然有问题，您可以在这里找到完整的代码： https://github.com/parmeshtoyou/Whosebug/tree/sof_23_oct_21

结果将如下所示：

在 android 工作室中计算 Java

Calculate in android studio Java

java

android

computer-science