Android自定义日历视图：使用GridView和适配器模式

这篇博客文章将指导您创建一个自定义的Android日历视图。我们将使用GridView来显示日历网格，并使用适配器模式来填充日期数据。

1. 创建CalendarView类

首先，创建一个名为CalendarView的新类，该类继承自LinearLayout。javaimport android.content.Context;import android.graphics.Color;import android.util.AttributeSet;import android.view.LayoutInflater;import android.view.View;import android.widget.GridView;import android.widget.LinearLayout;import android.widget.TextView;

import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Calendar;import java.util.Date;import java.util.HashSet;import java.util.List;import java.util.Locale;import java.util.Set;

public class CalendarView extends LinearLayout { private Context context; private GridView gridView; private TextView tvMonth; private CalendarAdapter adapter; private Calendar currentDate = Calendar.getInstance(); private SimpleDateFormat dateFormat = new SimpleDateFormat('MMMM yyyy', Locale.getDefault()); private Set markedDates = new HashSet<>();

public CalendarView(Context context) {        super(context);        this.context = context;        initialize();    }

public CalendarView(Context context, AttributeSet attrs) {        super(context, attrs);        this.context = context;        initialize();    }

public CalendarView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        this.context = context;        initialize();    }

private void initialize() {        LayoutInflater inflater = LayoutInflater.from(context);        inflater.inflate(R.layout.calendar_view, this);

    gridView = findViewById(R.id.gridview);        tvMonth = findViewById(R.id.tv_month);

    findViewById(R.id.btn_prev).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                currentDate.add(Calendar.MONTH, -1);                updateCalendar();            }        });

    findViewById(R.id.btn_next).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                currentDate.add(Calendar.MONTH, 1);                updateCalendar();            }        });

    updateCalendar();    }

public void markDate(Date date) {        markedDates.add(date);        adapter.notifyDataSetChanged();    }

private void updateCalendar() {        List<Date> dates = getDates();        adapter = new CalendarAdapter(context, dates, currentDate, markedDates);        gridView.setAdapter(adapter);        tvMonth.setText(dateFormat.format(currentDate.getTime()));    }

private List<Date> getDates() {        List<Date> dates = new ArrayList<>();        Calendar calendar = (Calendar) currentDate.clone();        calendar.set(Calendar.DAY_OF_MONTH, 1);        int firstDayOfWeek = calendar.get(Calendar.DAY_OF_WEEK) - 1;        calendar.add(Calendar.DAY_OF_MONTH, -firstDayOfWeek);

    while (dates.size() < 42) {            dates.add(calendar.getTime());            calendar.add(Calendar.DAY_OF_MONTH, 1);        }

    return dates;    }}

2. 创建布局文件

创建名为calendar_view.xml的布局文件，并在其中添加GridView、月份显示文本和导航按钮。xml

<LinearLayout        android:layout_width='match_parent'        android:layout_height='wrap_content'        android:gravity='center_vertical'        android:orientation='horizontal'>

    <Button            android:id='@+id/btn_prev'            android:layout_width='0dp'            android:layout_height='wrap_content'            android:layout_weight='1'            android:text='上一月' />

    <TextView            android:id='@+id/tv_month'            android:layout_width='0dp'            android:layout_height='wrap_content'            android:layout_weight='2'            android:gravity='center'            android:textSize='18sp' />

    <Button            android:id='@+id/btn_next'            android:layout_width='0dp'            android:layout_height='wrap_content'            android:layout_weight='1'            android:text='下一月' />    </LinearLayout>

<GridView        android:id='@+id/gridview'        android:layout_width='match_parent'        android:layout_height='wrap_content'        android:numColumns='7' />

3. 创建适配器类

创建一个名为CalendarAdapter的适配器类，用于管理日历网格中的日期数据。javaimport android.content.Context;import android.graphics.Color;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.TextView;

import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.List;import java.util.Locale;import java.util.Set;

public class CalendarAdapter extends BaseAdapter { private Context context; private List dates; private Calendar currentDate; private Set markedDates;

public CalendarAdapter(Context context, List<Date> dates, Calendar currentDate, Set<Date> markedDates) {        this.context = context;        this.dates = dates;        this.currentDate = currentDate;        this.markedDates = markedDates;    }

@Override    public int getCount() {        return dates.size();    }

@Override    public Object getItem(int position) {        return dates.get(position);    }

@Override    public long getItemId(int position) {        return position;    }

@Override    public View getView(int position, View convertView, ViewGroup parent) {        if (convertView == null) {            convertView = LayoutInflater.from(context).inflate(R.layout.calendar_item, parent, false);        }

    TextView tvDay = convertView.findViewById(R.id.tv_day);        Date date = dates.get(position);        SimpleDateFormat dateFormat = new SimpleDateFormat('d', Locale.getDefault());        tvDay.setText(dateFormat.format(date));

    if (date.getMonth() != currentDate.get(Calendar.MONTH)) {            tvDay.setTextColor(Color.GRAY);        } else if (isToday(date)) {            tvDay.setTextColor(Color.RED);        } else {            tvDay.setTextColor(Color.BLACK);        }

    if (markedDates.contains(date)) {            convertView.setBackgroundColor(Color.LTGRAY);        } else {            convertView.setBackgroundColor(Color.TRANSPARENT);        }

    return convertView;    }

private boolean isToday(Date date) {        Calendar today = Calendar.getInstance();        return date.getDate() == today.get(Calendar.DAY_OF_MONTH) &&                date.getMonth() == today.get(Calendar.MONTH) &&                date.getYear() == today.get(Calendar.YEAR);