The application for when the editText is not filled

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The application for when the editText is not filled

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#1 by (1 votes)
#2 by (0 votes)

1

Hello! I would like to ask for help. I'm new to Android studio and I'm trying to create an application for my physics students to calculate motion equations. One of the methods is to calculate the equation "V = v0 + at", when the editTexts are populated it works normal, but when one gets empty the application stops. I've tried in many ways to use methods that identify empty variables but it never works.

Follow the code below:

public void velocidadeTempo(View view){
    setContentView(R.layout.velocidade_tempo);

    final EditText editV0 = findViewById(R.id.editv0);
    final EditText editA = findViewById(R.id.edita);
    final EditText editT = findViewById(R.id.editt);

    final TextView tvV1 = findViewById(R.id.tvResultado);


    final double[] velocidadeF = new double[1];

    Button btcalcular = findViewById(R.id.btCalcular);

    btcalcular.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            String numv0 = editV0.getText().toString();
            double v0 = Double.parseDouble(numv0);

            String numa = editA.getText().toString();
            double a = Double.parseDouble(numa);

            String numt = editT.getText().toString();
            double t = Double.parseDouble(numt);

            velocidadeF[0] = v0 + (a*t);

            if(editV0.getText().toString().isEmpty()||editA.getText().toString().isEmpty()||editT.getText().toString().isEmpty()){
                tvV1.setText("sem resposta");
            }else{
                tvV1.setText(velocidadeF[0]+"");
            }

        }
    });
}

Remembering that the value "0" is valid in the equation.

android edittext

asked by anonymous 08.06.2018 / 02:58

2 answers

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score 1 · Answer 1

When the content of an EditText is used in a mathematical operation, it is necessary to ensure at least that:

is not null

if(editText.getText().toString().isEmpty()){
    // O conteúdo é nulo
}

represents a numeric value
```
<EditText
   android:id="@+id/edittext"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="0" 
   android:inputType="number"/>
```
The android:text="0" attribute assigns the value zero as the default value. The android:inputType="number" attribute causes only integer values to be accepted by EditText.

These validations must be made before the parse ( parse ) of the contents (String) to the corresponding numeric value.

Other validations may be required depending on the type of calculation to be performed.

score 0 · Answer 2

I used this here, modify your code and see if it works

if(!email.getText().toString().isEmpty() && !senha.getText().toString().isEmpty())
   validarLogin();
else
   Toast.makeText(LoginActivity.this, "Um ou mais campos estão vazios", Toast.LENGTH_SHORT).show();
}