Pull all event from Calendar

package idv.chatea.calendar;

import android.Manifest;
import android.content.ContentResolver;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.CalendarContract.Calendars;
import android.provider.CalendarContract.Events;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    // Projection array. Creating indices for this array instead of doing
    // dynamic lookups improves performance.
    public static final String[] EVENT_PROJECTION = new String[] {
            Calendars._ID,                           // 0
            Calendars.ACCOUNT_NAME,                  // 1
            Calendars.CALENDAR_DISPLAY_NAME,         // 2
            Calendars.OWNER_ACCOUNT,                 // 3
            Events.DESCRIPTION,                      // 4
    };

    // The indices for the projection array above.
    private static final int PROJECTION_ID_INDEX = 0;
    private static final int PROJECTION_ACCOUNT_NAME_INDEX = 1;
    private static final int PROJECTION_DISPLAY_NAME_INDEX = 2;
    private static final int PROJECTION_OWNER_ACCOUNT_INDEX = 3;
    private static final int PROJECTION_DESCRIPTION_INDEX = 4;

    private Button mButton;

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

        mButton = (Button) findViewById(R.id.button);
        mButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                runQuery();
            }
        });

        askPermission();
    }

    @Override
    protected void onStart() {
        super.onStart();
    }

    private void askPermission() {
        // Submit the query and get a Cursor object back.
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_CALENDAR) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_CALENDAR}, 100);
            return;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == 100) {
            boolean allGrant = true;
            for (int result: grantResults) {
                if (result != PackageManager.PERMISSION_GRANTED) {
                    allGrant = false;
                }
            }
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    @SuppressWarnings("MissingPermission")
    private void runQuery() {
        // Run query
        Cursor cur = null;
        ContentResolver cr = getContentResolver();

        Uri uri = Events.CONTENT_URI;
        String selection = "";
        String[] selectionArgs = new String[]{};

        cur = cr.query(uri, EVENT_PROJECTION, selection, selectionArgs, null);

        while (cur.moveToNext()) {
            long calID = 0;
            String displayName = null;
            String accountName = null;
            String ownerName = null;
            String description = null;

            // Get the field values
            calID = cur.getLong(PROJECTION_ID_INDEX);
            displayName = cur.getString(PROJECTION_DISPLAY_NAME_INDEX);
            accountName = cur.getString(PROJECTION_ACCOUNT_NAME_INDEX);
            ownerName = cur.getString(PROJECTION_OWNER_ACCOUNT_INDEX);
            description = cur.getString(PROJECTION_DESCRIPTION_INDEX);

            // Do something with the values...

            Log.d("TAG", calID + "," + displayName + "," + description);
        }

    }
}