How to Get Input from the User in Your Android App with Java

package com.allmycode.a06_01;

import android.support.v7.app.AppCompatActivity; import android.os.Bundle;

import android.view.View;

import android.widget.CheckBox;

import android.widget.EditText;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

EditText ageEditText;

CheckBox specialShowingCheckBox;

TextView outputTextView;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

ageEditText = (EditText) findViewById(R.id.ageEditText);

specialShowingCheckBox =

(CheckBox) findViewById(R.id.specialShowingCheckBox);

outputTextView = (TextView) findViewById(R.id.outputTextView);

}

public void onButtonClick(View view) {

<strong>int age = Integer.parseInt(ageEditText.getText().toString());</strong>

<strong>boolean isSpecialShowing = specialShowingCheckBox.isChecked();</strong>

boolean chargeDiscountPrice = (age < 18 || 65 <= age) && !isSpecialShowing;

outputTextView.setText(Boolean.toString(chargeDiscountPrice));

}

}

There's more to the app than the code. To create this app, you have to design the layout with its text fields, its check box, and its button. You also have to set the button's onClick property to "onButtonClick".

Getting a discounted movie ticket.

But, in this image, the user has selected the check box. So, when Android executes the code, the expression specialShowingCheckBox.isChecked() has the value true.

Paying the full price for a movie ticket.

To make the code work, you have to associate the variable names ageEditText, specialShowingCheckBox, and outputTextView with the correct thingamajigs on the device's screen. The findViewById statements help you do that.