TimePicker

package com.thieumao.asm2;

import android.annotation.TargetApi;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.Toast;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    private AlarmManager alarmManager;
    private TimePicker timePicker;
    private TextView updateText;
    private Context context;
    private Calendar calendar;
    private PendingIntent pendingIntent;
    private Intent myIntent;
    private int hourTimePicker;
    private int minuteTimePicker;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.context = this;
        getTimeNow();
        alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
        timePicker = (TimePicker) findViewById(R.id.timePicker);
        timePicker.setEnabled(true);
        timePicker.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
            @Override
            public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {
//                Toast.makeText(MainActivity.this, "gio " + hourOfDay, Toast.LENGTH_SHORT).show();
                hourTimePicker = hourOfDay;
                minuteTimePicker = minute;
            }
        });
        updateText  = (TextView) findViewById(R.id.tvUpdate);
        calendar = Calendar.getInstance();
        myIntent = new Intent(this.context, AlarmReceiver.class);
    }

    private void getTimeNow() {
        Calendar c = Calendar.getInstance();
        hourTimePicker = c.get(Calendar.HOUR_OF_DAY);
        minuteTimePicker = c.get(Calendar.MINUTE);
    }

    public void turnOnAlarm(View view) {
        calendar.set(Calendar.HOUR_OF_DAY, hourTimePicker);
        calendar.set(Calendar.MINUTE, minuteTimePicker);
        String hour_string = String.valueOf(hourTimePicker);
        String minute_string = String.valueOf(minuteTimePicker);
        if (hourTimePicker > 12) {
            hour_string = String.valueOf(hourTimePicker - 12);
        }
        if (minuteTimePicker < 10) {
            minute_string = "0" + String.valueOf(minuteTimePicker);
        }
        setAlarmText("Alarm set to: " + hour_string + ":" + minute_string);
        pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0, myIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), pendingIntent);
    }

    public void turnOffAlarm(View view) {
        setAlarmText("Alarm Off");
        alarmManager.cancel(pendingIntent);
    }

    private void setAlarmText(String output) {
        updateText.setText(output);
    }

}