ALG - Session 1 - MainActivity.java

MainActivity.java

package com.weddingwire.android.learninggroup.session1;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

/**
 * Activity to increment a textfield on button press.
 */
public class MainActivity extends Activity {

    /** Member variable keeping track of the count. */
    private int counter = 0;
    
    /** Member variable keeping reference to textview. */
    private TextView textView;

    /** onCreate is called before onResume(). */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        // Link this activity with the xml layout file.
        setContentView(R.layout.activity_main);

        // Get a reference to the TextView we'll update on button tap.
        textView = (TextView) findViewById(R.id.textView);
        textView.setText(Integer.toString(counter));

        // Get a reference to the button
        Button button = (Button) findViewById(R.id.button);

        // Add a listener to the button.
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Increment the counter and set the text.
                counter++;
                textView.setText(Integer.toString(counter));
            }
        });
    }

    /** onResume() is called after onCreate() on first app launch and when 
     *  resuming an app from the background/sleep. 
     */
    @Override
    protected void onResume() {
        super.onResume();
        // To demonstrate when onResume() is called in the Activity lifecycle.
        textView.setText("on resume");
    }
}

activity_main.xml can be found here: https://gist.github.com/loeschg/74d6b372b3802dec6727