我如何使用 if else 语句在 android 工作室的 EditText 中输入数字

Question

im new to android, but im developing an application that has conditions in the background.i want if some one inputs the AVB number in the first EditText, the second one should be automatically filled from the ranges in the if statement and then multiplies and puts the answer in the tfeed TextView. please help me out as soon as possible. Here is my fish_feed.java class

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Fish_Feed extends AppCompatActivity {
    EditText number1;
    EditText number2;

    TextView total_feed;

    Button calc;
    double num1,num2,product ;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fish_feed);

        Toolbar toolbar = findViewById(R.id.feed_fry);
        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("Calculate Feed Per Fish in a day");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);


        number1 = (EditText)findViewById(R.id.abw);
        number2 = (EditText)findViewById(R.id.fish);

        total_feed = (TextView) findViewById(R.id.tfeed);


        calc = (Button) findViewById(R.id.feed);

        calc.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1 = Double.parseDouble(number1.getText().toString());
                num2 = Double.parseDouble(number2.getText().toString());

                product = num1*(num2/100) ;
                if (num1 < 2){
                  number2.setText((int) 16.5) ;
                   }
                else if(num1 >=2 && num1<=10){
                    number2.setText((int) 7) ;
                }
                else if(num1 >=10 && num1<=100){
                    number2.setText((int) 3) ;
                }
                else if(num1 >=100 && num1<=500){
                    number2.setText((int) 1.5) ;
                }
                else if(num1 >500){
                    number2.setText((int) 1) ;
                }

                total_feed.setText("Number of fish to be stocked is "  + product);
                   
            }
        });
    }
}

**And the activity_fish_feed**
   <?xml version="1.0" encoding="utf-8"?>
<ScrollView android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">

    <LinearLayout 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:orientation="vertical"
        tools:context=".Fish_Feed">

        <androidx.appcompat.widget.Toolbar
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/feed_fry"
            app:titleTextColor="#fff"
            android:background="#FF018786"
            />



        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Enter Average Body Weight of Your Fish"
            android:textSize="20sp"
            android:textColor="#000"
            android:layout_marginTop="15dp"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"/>

        <EditText
            android:id="@+id/abw"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="number"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"
            android:hint="Enter your ABW"
            />

        <EditText
            android:id="@+id/fish"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="20sp"
            android:textColor="#000"
            android:layout_marginTop="15dp"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"/>

        <Button
            android:id="@+id/feed"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            android:backgroundTint="#FF018786"
            android:text="CALCULATE TOTAL FEED"
            android:layout_marginLeft="30dp"
            android:textColor="@color/white"
            app:layout_constraintEnd_toEndOf="@+id/yield"
            app:layout_constraintTop_toBottomOf="@+id/yield" />

        <TextView
            android:id="@+id/tfeed"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textSize="20sp"
            android:textColor="#000"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"/>
    </LinearLayout>

</ScrollView>

Answer 1

Try this once -

XML File-

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/feed_fry"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#FF018786"
            app:titleTextColor="#fff" />


        <TextView

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginTop="15dp"
            android:layout_marginEnd="16dp"
            android:text="Enter Average Body Weight of Your Fish"
            android:textColor="#000"
            android:textSize="20sp" />

        <EditText
            android:id="@+id/abw"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"
            android:hint="Enter your ABW"
            android:inputType="number" />

        <EditText
            android:id="@+id/fish"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginTop="15dp"
            android:layout_marginEnd="16dp"
            android:enabled="false"
            android:textColor="#000"
            android:textSize="20sp" />

        <Button
            android:id="@+id/feed"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="30dp"
            android:layout_marginTop="16dp"
            android:backgroundTint="#FF018786"
            android:text="CALCULATE TOTAL FEED"
            android:textColor="@color/white"
            app:layout_constraintEnd_toEndOf="@+id/yield"
            app:layout_constraintTop_toBottomOf="@+id/yield" />

        <TextView
            android:id="@+id/tfeed"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginEnd="16dp"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textColor="#000"
            android:textSize="20sp" />
    </LinearLayout>

</ScrollView>

Activity File

import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;

public class MainActivity2 extends AppCompatActivity {
    EditText number1;
    EditText number2;

    TextView total_feed;

    Button calc;
    double product;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);


        Toolbar toolbar = findViewById(R.id.feed_fry);
        toolbar.setTitle("Calculate Feed Per Fish in a day");


        number1 = findViewById(R.id.abw);
        number2 = findViewById(R.id.fish);

        total_feed = findViewById(R.id.tfeed);

        number1.addTextChangedListener(new TextWatcher() {

            public void afterTextChanged(Editable s) {
            }

            public void beforeTextChanged(CharSequence s, int start,
                                          int count, int after) {
            }

            public void onTextChanged(CharSequence s, int start,
                                      int before, int count) {
                if (s.length() == 0) {
                    number2.setText("");
                    total_feed.setText("");
                } else {
                    double number;
                    int value = Integer.parseInt(String.valueOf(s));
                    if (value < 2) {
                        number = 16.5;
                    } else if (value >= 2 && value <= 10) {
                        number = 7;
                    } else if (value >= 10 && value <= 100) {
                        number = 3;
                    } else if (value >= 100 && value <= 500) {
                        number = 1.5;
                    } else if (value > 500) {
                        number = 1;
                    } else {
                        number = 0;
                    }
                    number2.setText(String.valueOf(number));
                }
            }
        });

        calc = findViewById(R.id.feed);

        calc.setOnClickListener(v -> {
            String num1 = number1.getText().toString().trim();
            String num2 = number2.getText().toString().trim();
            if (num1.isEmpty() && num2.isEmpty()) {
                Toast.makeText(getApplicationContext(), "Add Num", Toast.LENGTH_LONG).show();
            } else {
                product = Double.parseDouble(num1) * (Double.parseDouble(num2) / 100);
                total_feed.setText("Number of fish to be stocked is " + product);
            }
        });
    }
}

Answer 2

You have to use TextChangeListener and you are setting text as int which refers to string resource ID. You can use hardcoded string as follows

 number1.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
        }

        @Override
        public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            try {

                num1 = Double.parseDouble(charSequence.toString());

                if (num1 < 2){
                    number2.setText("16") ;
                }
                else if(num1 >=2 && num1<=10){
                    number2.setText("3") ;
                }
                else if(num1 >=10 && num1<=100){
                    number2.setText("3") ;
                }
                else if(num1 >=100 && num1<=500){
                    number2.setText("1") ;
                }
                else if(num1 >500){
                    number2.setText("1") ;
                }
            }catch (Exception e){
                e.printStackTrace();
            }

        }

        @Override
        public void afterTextChanged(Editable editable) {

        }
    });