android 自带日历控件datePicker

//这就是一个点击事件,点击打开日历拾取器

selectDate.setOnClickListener(new View.OnClickListener() {    @Override    public void onClick(View view1) {        AlertDialog.Builder builder = new AlertDialog.Builder(BooksActivity.this);        View view = getLayoutInflater().inflate(R.layout.activity_dialog_date, null);//这个布局在下边,可参考        final DatePicker datePicker = (DatePicker) view.findViewById(R.id.date_picker);        //设置日期简略显示 否则详细显示 包括:星期周        datePicker.setCalendarViewShown(false);        //初始化当前日期        calendar.setTimeInMillis(System.currentTimeMillis());        //初始化当前日期        calendar.setTimeInMillis(System.currentTimeMillis());        datePicker.init(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),                calendar.get(Calendar.DAY_OF_MONTH), null);        /**         * 下面这行代吗 设置的是只显示年月         */        ((ViewGroup) ((ViewGroup) datePicker.getChildAt(0)).getChildAt(0)).getChildAt(2).setVisibility(View.GONE);        //设置date布局        builder.setView(view);        builder.setTitle("设置日期信息");        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialogInterface, int i) {                int year = datePicker.getYear();                int month = datePicker.getMonth()+1;//我勒个去,系统获取的日期居然不准             }        });        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialogInterface, int i) {                dialog.cancel();            }        });        dialog = builder.create();        dialog.show();    }});

//布局文件

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/activity_coupon"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:fitsSystemWindows="true"    android:background="@color/color_retangle"    >        <DatePicker            android:id="@+id/date_picker"            android:layout_gravity="center"            android:layout_height="wrap_content"            android:layout_width="wrap_content"            android:datePickerMode="spinner"            >        </DatePicker></LinearLayout>