Android日历签到，超级简单的实现方式

上来就干，是我一贯的作风！

先预览下效果图

未签到效果.png 已签到效果.png

分析控件结构：
从上到下依次是TextView→GridView→GridView
布局代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white">
    <TextView
        android:id="@+id/tvYear"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="2017年7月"
        android:gravity="center"
        android:textColor="@android:color/white"
        android:background="@color/colorAccent"/>
    <com.lida.signdate.InnerGridView
        android:id="@+id/gvWeek"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:numColumns="7">
    </com.lida.signdate.InnerGridView>
    <com.lida.signdate.InnerGridView
        android:id="@+id/gvDate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:numColumns="7">
    </com.lida.signdate.InnerGridView>
</LinearLayout>

1、tvYear负责显示年月。

2、gvWeek负责显示星期几

3、gvDate负责显示日历

把整体布局作为组合控件封装在SignDate类里面，SignDate主要代码如下：

public class SignDate extends LinearLayout {

    private TextView tvYear;
    private InnerGridView gvWeek;
    private InnerGridView gvDate;
    private AdapterDate adapterDate;

    public SignDate(Context context) {
        super(context);
        init();
    }

   ...

    private void init(){
        View view = View.inflate(getContext(),R.layout.layout_signdate,this);
        tvYear = view.findViewById(R.id.tvYear);
        gvWeek = view.findViewById(R.id.gvWeek);
        gvDate = view.findViewById(R.id.gvDate);
        tvYear.setText(DateUtil.getCurrentYearAndMonth());
        gvWeek.setAdapter(new AdapterWeek(getContext()));
        adapterDate = new AdapterDate(getContext());
        gvDate.setAdapter(adapterDate);
    }

    /**
     * 签到成功的回调
     * @param onSignedSuccess
     */
    public void setOnSignedSuccess(OnSignedSuccess onSignedSuccess){
        adapterDate.setOnSignedSuccess(onSignedSuccess);
    }
}

代码中AdapterWeek就是简单的设置星期几数据，这里不多介绍。
在AdapterDate中实现了本月天数计算，开始天数应该显示在星期几的位置，和点击签到实现签到效果，代码如下：

public class AdapterDate extends BaseAdapter {

    private Context context;
    private List<Integer> days = new ArrayList<>();
    //日历数据
    private List<Boolean> status = new ArrayList<>();
    //签到状态，实际应用中初始化签到状态可通过该字段传递
    private OnSignedSuccess onSignedSuccess;
    //签到成功的回调方法，相应的可自行添加签到失败时的回调方法

    public AdapterDate(Context context) {
        this.context = context;
        int maxDay = DateUtil.getCurrentMonthLastDay();//获取当月天数
        for (int i = 0; i < DateUtil.getFirstDayOfMonth() - 1; i++) {
            //DateUtil.getFirstDayOfMonth()获取当月第一天是星期几，星期日是第一天，依次类推
            days.add(0);
            //0代表需要隐藏的item
            status.add(false);
            //false代表为签到状态
        }
        for (int i = 0; i < maxDay; i++) {
            days.add(i+1);
            //初始化日历数据
            status.add(false);
            //初始化日历签到状态
        }
    }

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

    @Override
    public Object getItem(int i) {
        return days.get(i);
    }

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

    @Override
    public View getView(final int i, View view, ViewGroup viewGroup) {
        ViewHolder viewHolder;
        if(view==null){
            view = LayoutInflater.from(context).inflate(R.layout.item_gv,null);
            viewHolder = new ViewHolder();
            view.setTag(viewHolder);
        }else{
            viewHolder = (ViewHolder) view.getTag();
        }
        viewHolder.tv = view.findViewById(R.id.tvWeek);
        viewHolder.rlItem = view.findViewById(R.id.rlItem);
        viewHolder.ivStatus = view.findViewById(R.id.ivStatus);
        viewHolder.tv.setText(days.get(i)+"");
        if(days.get(i)==0){
            viewHolder.rlItem.setVisibility(View.GONE);
        }
        if(status.get(i)){
            viewHolder.tv.setTextColor(Color.parseColor("#FD0000"));
            viewHolder.ivStatus.setVisibility(View.VISIBLE);
        }else{
            viewHolder.tv.setTextColor(Color.parseColor("#666666"));
            viewHolder.ivStatus.setVisibility(View.GONE);
        }
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(status.get(i)){
                    Toast.makeText(context,"Already sign in!",Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(context,"Sign in success!",Toast.LENGTH_SHORT).show();
                    status.set(i,true);
                    notifyDataSetChanged();
                    if(onSignedSuccess!=null){
                        onSignedSuccess.OnSignedSuccess();
                    }
                }
            }
        });
        return view;
    }

    class ViewHolder{
        RelativeLayout rlItem;
        TextView tv;
        ImageView ivStatus;
    }

    public void setOnSignedSuccess(OnSignedSuccess onSignedSuccess){
        this.onSignedSuccess = onSignedSuccess;
    }
}

代码实在简单，没有什么技术上的难点，初始化数据、签到失败回调、界面效果等一些功能，大家可以自行补充。
工程源码地址：https://github.com/StormFeng/SignDate