How to show text instead numbers as a result of a math formula in Android App?

Question

How are you? I need help with my first Android App.

I want to calculate the result of the gasoline price divided by the etanol price. I've already done that, with the result being displayed in the app.

But now I want to make it better. Instead of a number, I want the text field to display "Gasoline", if the result of gasoline / etanol is equal or greater than 0.7, and "Etanol", if the result is lower than 0.7.

How can I do that? I'm adding the code I already have. Thanks!

    package br.com.espacoporto.espacoporto;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Inicio extends AppCompatActivity {

    TextView totalTextView;
    EditText gasolineTxt;
    EditText etanolTxt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_inicio);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        totalTextView = (TextView) findViewById(R.id.totalTextView);
        gasolineTxt = (EditText) findViewById(R.id.gasolineTxt);
        etanolTxt = (EditText) findViewById(R.id.etanolTxt);

        Button calcBtn = (Button) findViewById(R.id.calcBtn);
        calcBtn.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                float gasoline = Float.parseFloat(gasolineTxt.getText().toString());
                float etanol = Float.parseFloat(etanolTxt.getText().toString());
                float total = etanol / gasoline;
                totalTextView.setText(Float.toString(total));
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_inicio, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Just create a condition based on `total` where you hit `totalTextView.setText("Gasoline");` or `totalTextView.setText("Ethanol");` — Daniel, Jun 14 '16 at 01:19

score 2 · Accepted Answer · answered Jun 14 '16 at 01:21

2

Should just be a simple if statement, yeah?

Also, your question said gasoline / etanol, so I used that instead of what you had in the code.

float total = gasoline / etanol;
if (total < 0.7)
    totalTextView.setText("Ethanol");
else 
    totalTextView.setText("Gasoline");

Or you can one-line that

totalTextView.setText( (gasoline / etanol) < 0.7 ? "Ethanol" : "Gasoline");

answered Jun 14 '16 at 01:21

OneCricketeer

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Do you mind if I ask why the "totalTextView.setText( (gasoline / etanol) < 0.7 ? "Ethanol" : "Gasoline");" worked? I haven't learned the "?" and the ":". Thanks – Lucas Pereira Jun 14 '16 at 01:24
1

@LucasPereira http://stackoverflow.com/questions/798545/what-is-the-java-operator-called-and-what-does-it-do – Arjan Jun 14 '16 at 01:26

How to show text instead numbers as a result of a math formula in Android App?

1 Answers1