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Greetings dear fellow programmers
Are you all right? I hope so
I’m doing this publication because I’m having a lot of difficulty to understand a specific parameter of the listeners of Android Studio, in specific of Onclick, and as I realized that many functions of the development environment carry this same structure, I decided to do this topic
The code in question proposed by the exercise is as follows:.
public class MainActivity extends AppCompatActivity {
private EditText precoGasolina;
private EditText precoEtanol;
private Button botaoVerificar;
private TextView textoResultado;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
precoGasolina =(EditText)findViewById(R.id.txt_gasolina);
precoEtanol = (EditText)findViewById(R.id.txt_etanol);
textoResultado = (TextView)findViewById(R.id.lbl_resultado);
botaoVerificar = (Button)findViewById(R.id.btn_calcular);
botaoVerificar.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v){
//Recupera valores digitados
String textoPrecoAlcool = precoEtanol.getText().toString();
String textoPrecoGasolina = precoGasolina.getText().toString();
//Conveterter valores strings para numeros;
Double valorEtanol = Double.parseDouble(textoPrecoAlcool);
Double valorGasolina = Double.parseDouble(textoPrecoGasolina);
double resultado = valorEtanol/valorGasolina;
if (resultado >= 0.7){
textoResultado.setText(resultado + "É melhor utilizar gasolina");
}else{
textoResultado.setText(resultado + "É melhor utilizar Etanol");
}
}
});
}
}
My big doubt lies within the
onClick(View v){
I know what the View v argument works for, it serves to access button attributes, but my doubt is how I can pass an argument without referencing the button and it can interpret that I’m treating the button object?