show a month/year picker on clicking on the month

app/src/main/java/calendar/simplemobiletools/com/MainActivity.java

@@ -19,7 +19,8 @@ import butterknife.BindDimen;
 import butterknife.ButterKnife;
 import butterknife.OnClick;
 
-public class MainActivity extends AppCompatActivity {
+public class MainActivity extends AppCompatActivity implements MyDatePickerDialog.DatePickedListener {
+    public static final String DATE = "date";
     private static final String DATE_PATTERN = "ddMMYYYY";
     private static final String YEAR_PATTERN = "YYYY";
 
@@ -118,6 +119,15 @@ public class MainActivity extends AppCompatActivity {
         fillCalendar();
     }
 
+    @OnClick(R.id.table_month)
+    public void pickMonth() {
+        final MyDatePickerDialog dialog = new MyDatePickerDialog();
+        final Bundle bundle = new Bundle();
+        bundle.putString(DATE, targetDate.toString());
+        dialog.setArguments(bundle);
+        dialog.show(getSupportFragmentManager(), "datepicker");
+    }
+
     private String getMonthName() {
         final String[] months = new DateFormatSymbols().getMonths();
         final StringBuilder sb = new StringBuilder();
@@ -130,4 +140,10 @@ public class MainActivity extends AppCompatActivity {
         }
         return sb.toString();
     }
+
+    @Override
+    public void onDatePicked(DateTime dateTime) {
+        targetDate = dateTime;
+        fillCalendar();
+    }
 }

app/src/main/java/calendar/simplemobiletools/com/MyDatePickerDialog.java

@@ -0,0 +1,52 @@
+package calendar.simplemobiletools.com;
+
+import android.app.Dialog;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.DialogFragment;
+import android.support.v7.app.AlertDialog;
+import android.view.View;
+import android.widget.DatePicker;
+import android.widget.LinearLayout;
+
+import org.joda.time.DateTime;
+
+public class MyDatePickerDialog extends DialogFragment {
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        final AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
+        final View view = getActivity().getLayoutInflater().inflate(R.layout.date_picker, null);
+        final DatePicker datePicker = (DatePicker) view.findViewById(R.id.date_picker);
+        hideDayPicker(datePicker);
+
+        final Bundle bundle = getArguments();
+        if (bundle != null && bundle.containsKey(MainActivity.DATE)) {
+            final DateTime dateTime = new DateTime(bundle.getString(MainActivity.DATE));
+            datePicker.init(dateTime.getYear(), dateTime.getMonthOfYear() - 1, 1, null);
+        }
+
+        builder.setView(view);
+        view.findViewById(R.id.date_picker_ok).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                final DatePickedListener listener = (DatePickedListener) getActivity();
+                final int month = datePicker.getMonth() + 1;
+                final int year = datePicker.getYear();
+                listener.onDatePicked(new DateTime().withMonthOfYear(month).withYear(year));
+                dismiss();
+            }
+        });
+        return builder.create();
+    }
+
+    private void hideDayPicker(DatePicker datePicker) {
+        final LinearLayout ll = (LinearLayout) datePicker.getChildAt(0);
+        final LinearLayout ll2 = (LinearLayout) ll.getChildAt(0);
+        ll2.getChildAt(0).setVisibility(View.GONE);
+    }
+
+    public interface DatePickedListener {
+        void onDatePicked(DateTime dateTime);
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -22,6 +22,8 @@
         android:id="@+id/table_month"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
+        android:layout_toLeftOf="@+id/right_arrow"
+        android:layout_toRightOf="@+id/left_arrow"
         android:gravity="center_horizontal"
         android:paddingBottom="@dimen/activity_margin"
         android:paddingTop="@dimen/activity_margin"
@@ -47,7 +49,6 @@
         android:layout_below="@+id/table_month"
         android:layout_marginBottom="@dimen/activity_margin"
         android:layout_marginTop="@dimen/activity_margin"
-        android:gravity="center">
+        android:gravity="center"/>
 
-    </TableLayout>
 </RelativeLayout>

app/src/main/res/layout/date_picker.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+                android:layout_width="wrap_content"
+                android:layout_height="match_parent"
+                android:gravity="center_horizontal">
+
+    <DatePicker
+        android:id="@+id/date_picker"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:calendarViewShown="false"
+        android:datePickerMode="spinner"/>
+
+    <Button
+        android:id="@+id/date_picker_ok"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_alignLeft="@id/date_picker"
+        android:layout_alignRight="@id/date_picker"
+        android:layout_below="@id/date_picker"
+        android:text="OK"/>
+
+</RelativeLayout>