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

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        TextView tvDate = (TextView) findViewById(R.id.date);
        TextView tvHeure = (TextView) findViewById(R.id.heure);


        Calendar calendar = Calendar.getInstance();

        int jour = calendar.get(Calendar.DAY_OF_MONTH);
        int mois = calendar.get(Calendar.MONTH) + 1;
        int annee = calendar.get(Calendar.YEAR);

        int heure = calendar.get(Calendar.HOUR_OF_DAY);
        int minute = calendar.get(Calendar.MINUTE);

        tvDate.setText(jour + "/" + mois + "/" + annee);

        String zero = "";
        if (minute < 10)
            zero = "0";
        tvHeure.setText(heure + ":" + zero + minute);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.formation.currenttime.MainActivity"
    android:orientation="vertical"
    android:gravity="center"
    >

    <TextView
        android:id="@+id/date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="date" />

    <TextView
        android:id="@+id/heure"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="heure" />

</LinearLayout>