안드로이드 커스텀 달력 만들기 - MainActivity

Layout 을 화면에 뿌릴 MainActivity.java 코드를 아래와 같이 구현했다.

package com.link2me.android.calendar; import android.content.Context; import android.content.DialogInterface; import android.os.Bundle; import android.text.format.DateFormat; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.widget.EditText; import android.widget.GridView; import android.widget.ImageView; import android.widget.TextView; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import com.link2me.android.adpater.GridCellAdapter; import java.util.Calendar; import java.util.Locale; public class MainActivity extends AppCompatActivity implements View.OnClickListener {     private static final String TAG = MainActivity.class.getSimpleName();     private Context mContext;     private TextView currentMonth;     private ImageView prevYear;     private ImageView prevMonth;     private ImageView nextMonth;     private ImageView nextYear;     private ImageView selectDate;     private GridView calendarView;     private GridCellAdapter adapter;     private Calendar cal;     private int month, year;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);         mContext = MainActivity.this;         cal = Calendar.getInstance(Locale.getDefault());         month = cal.get(Calendar.MONTH) + 1;         year = cal.get(Calendar.YEAR);         prevYear = (ImageView) this.findViewById(R.id.prevYear);         prevYear.setOnClickListener(this);         prevMonth = (ImageView) this.findViewById(R.id.prevMonth);         prevMonth.setOnClickListener(this);         currentMonth = (TextView) this.findViewById(R.id.currentMonth);         currentMonth.setText(year +"년 " + month + "월");         currentMonth.setOnClickListener(this);         nextMonth = (ImageView) this.findViewById(R.id.nextMonth);         nextMonth.setOnClickListener(this);         nextYear = (ImageView) this.findViewById(R.id.nextYear);         nextYear.setOnClickListener(this);         selectDate = (ImageView) this.findViewById(R.id.selectDate);         selectDate.setOnClickListener(this);         calendarView = (GridView) this.findViewById(R.id.calendar);         // Initialised         adapter = new GridCellAdapter(mContext, month, year);         adapter.notifyDataSetChanged();         calendarView.setAdapter(adapter);     }     private void setGridCellAdapterToDate(int month, int year) {         adapter = new GridCellAdapter(mContext, month, year);         adapter.notifyDataSetChanged();         calendarView.setAdapter(adapter);         // 상단 화면 날짜 출력         currentMonth.setText(year +"년 " + month + "월");     }     @Override     public void onClick(View view) {         switch (view.getId()) {             case R.id.prevYear:                 year--;                 setGridCellAdapterToDate(month, year);                 break;             case R.id.prevMonth:                 if (month <= 1) {                     month = 12;                     year--;                 } else {                     month--;                 }                 setGridCellAdapterToDate(month, year);                 break;             case R.id.currentMonth:                 cal = Calendar.getInstance(Locale.getDefault()); // 현재날짜와 시간으로 설정된다.                 month = cal.get(Calendar.MONTH) + 1; // 0 ~ 11월을 반환하므로 + 1을 해준다.                 year = cal.get(Calendar.YEAR);                 setGridCellAdapterToDate(month, year);                 break;             case R.id.nextMonth:                 if (month > 11) {                     month = 1;                     year++;                 } else {                     month++;                 }                 setGridCellAdapterToDate(month, year);                 break;             case R.id.nextYear:                 year++;                 setGridCellAdapterToDate(month, year);                 break;             case R.id.selectDate:                 LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);                 final View layout = inflater.inflate(R.layout.select_calendar_input,null);                 AlertDialog.Builder cal_confirm = new AlertDialog.Builder(mContext);                 cal_confirm.setTitle("검색할 년도 입력");                 cal_confirm.setView(layout);                 final EditText etYear = layout.findViewById(R.id.selectYear);                 final EditText etMonth = layout.findViewById(R.id.selectMonth);                 // 확인 버튼 설정                 cal_confirm.setPositiveButton("검색", new DialogInterface.OnClickListener() {                     @Override                     public void onClick(DialogInterface dialog, int which) {                         String selectYear = etYear.getText().toString().trim();                         if(selectYear.length() == 0) {                             AlertDialog.Builder phoneNO_confirm = new AlertDialog.Builder(mContext);                             phoneNO_confirm.setMessage("년도를 입력하세요.").setCancelable(false).setPositiveButton("확인",                                     new DialogInterface.OnClickListener() {                                         @Override                                         public void onClick(DialogInterface dialog, int which) { // 'YES'                                             dialog.dismiss();                                         }                                     });                             AlertDialog alert = phoneNO_confirm.create();                             alert.show();                             return;                         }                         String selectMonth = etMonth.getText().toString().trim();                         if(selectMonth.length() == 0) {                             AlertDialog.Builder phoneNO_confirm = new AlertDialog.Builder(mContext);                             phoneNO_confirm.setMessage("월(月)을 입력하세요.").setCancelable(false).setPositiveButton("확인",                                     new DialogInterface.OnClickListener() {                                         @Override                                         public void onClick(DialogInterface dialog, int which) { // 'YES'                                             dialog.dismiss();                                         }                                     });                             AlertDialog alert = phoneNO_confirm.create();                             alert.show();                             return;                         }                         month = Integer.parseInt(selectMonth);                         year = Integer.parseInt(selectYear);                         setGridCellAdapterToDate(month, year);                     }                 });                 cal_confirm.setNegativeButton("취소", new DialogInterface.OnClickListener() {                     @Override                     public void onClick(DialogInterface dialog, int which) {                         dialog.dismiss();                     }                 });                 cal_confirm.show();                 break;         }     }     @Override     public void onDestroy() {         Log.d(TAG, "Destroying View ...");         super.onDestroy();     } }

화면에 출력할 데이터는 GridCellAdapter 를 만들어서 뿌려주면 된다.