<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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=".Lastcall">

    <TextView
        android:id="@+id/lc"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

package pt.ubi.di.pdm.expermissions1;

import android.app.Activity;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.CallLog;
import android.widget.TextView;

public class Lastcall extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_lastcall);
        TextView oTV = (TextView)findViewById(R.id.lc);
        String strUriCalls = "content://call_log/calls";
        Uri uriCalls=Uri.parse(strUriCalls);
        Cursor curCalls = getContentResolver().query(uriCalls ,null ,null ,null , null);
        String sInfo = "Last Call:";


        if (curCalls.moveToLast())
            sInfo += curCalls.getString(curCalls.getColumnIndex(CallLog.Calls.NUMBER))+"n" +
                    "Duration:"+curCalls.getString(curCalls.getColumnIndex(CallLog.Calls.DURATION));
        oTV.setText(sInfo);

    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pt.ubi.di.pdm.expermissions1">
    <uses-permission
        android:name="android.permission.READ_CALL_LOG"></uses-permission>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".Lastcall">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>