Android Kotlin 实现底部弹框日历组件的案例

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#98adabab">
    <relativelayout
        android:id="@+id/dialog_bottom"
        android:layout_width="match_parent"
        android:layout_height="320dp"
        android:layout_alignparentbottom="true"
        android:layout_centerhorizontal="true"
        android:background="@drawable/rounded_button_white"
        android:padding="20dp">
        <linearlayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginbottom="40dp">
            <textview
                android:id="@+id/cancel"
                android:layout_width="0dp"
                android:layout_weight="1.5"
                android:layout_height="38dp"
                android:layout_gravity="center_horizontal"
                android:text="cancel"
                android:textallcaps="false"
                android:textcolor="@color/colorprimary"
                android:textsize="14sp"
                android:gravity="center"
                />
            <textview
                android:id="@+id/title"
                android:layout_width="0dp"
                android:layout_weight="5"
                android:layout_height="38dp"
                android:layout_gravity="center_horizontal"
                android:text="date of birth"
                android:textallcaps="false"
                android:textcolor="@color/colorprimary"
                android:textsize="16sp"
                android:gravity="center"
                />
            <textview
                android:id="@+id/save"
                android:layout_width="0dp"
                android:layout_weight="1.5"
                android:layout_height="38dp"
                android:layout_gravity="center_horizontal"
                android:layout_margintop="139dp"
                android:text="save"
                android:textallcaps="false"
                android:gravity="center"
                android:textcolor="@color/colorprimary"
                android:textsize="14sp" />
        </linearlayout>
        <linearlayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margintop="40dp"
            android:gravity="center_horizontal"
            android:orientation="vertical">
            <linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical"
                android:padding="5dp">
				// 这个是最关键的
                <datepicker
                    android:id="@+id/dp_date"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:calendarviewshown="false"
                    android:datepickermode="spinner"
                    />
            </linearlayout>
        </linearlayout>
    </relativelayout>
</relativelayout>

import java.util.date
/**
 * 个人信息页
 */
class personnalinfoactivity : appcompatactivity() {
    private var year: string? = null
    private var month: string? = null
    private var day: string? = null
    @requiresapi(build.version_codes.n)
    override fun oncreate(savedinstancestate: bundle?) {
        super.oncreate(savedinstancestate)
        setcontentview(r.layout.activity_personal_info)
        birthday.setonclicklistener {
            choosebirthfun()
        }
    }
    private fun choosebirthfun() = run {
        val userinfo = sharedprefs.loaduserfrompreferences(this@personnalinfoactivity)
        val view = layoutinflater.inflate(r.layout.custom_bottom_datepicker, null)
        val popupwindow = popupwindow(
            view,
            viewgroup.layoutparams.match_parent,
            viewgroup.layoutparams.match_parent,
            true
        )
        // 设置popupwindow是否能响应外部点击事件
        popupwindow.isoutsidetouchable = true
        // 设置popupwindow是否能响应点击事件
        popupwindow.istouchable = true
        // 设置popupwindow弹出窗体的背景
        popupwindow.setbackgrounddrawable(
            colordrawable(
                contextcompat.getcolor(
                    this,
                    android.r.color.transparent
                )
            )
        )
        // 设置popupwindow从底部弹出
        popupwindow.showatlocation(view, gravity.bottom, 0, 0)
        val save = view.findviewbyid<textview>(r.id.save)
        val cancel = view.findviewbyid<textview>(r.id.cancel)
        val dpdate = view.findviewbyid<datepicker>(r.id.dp_date);
        // 设置默认日期
        if (userinfo != null) {
            if (userinfo.birthday == "") {
                dpdate.init(1970, 0, 1, null);
            } else {
                year?.let {
                    (month)?.let { it1 ->
                        day?.let { it2 ->
                            dpdate.init(
                                it.toint(),
                                (it1.toint()) - 1,
                                it2.toint(),
                                null
                            )
                        }
                    }
                };
            }
        }
        save.setonclicklistener {
            if (popupwindow.isshowing) {
                year = dpdate.getyear().tostring()
                month = ((dpdate.getmonth() + 1).tostring())
                day = dpdate.getdayofmonth().tostring()
                val birthstr = "${year}-${month}-${day}"
                // 此处可以处理选择好的日期
                popupwindow.dismiss()
            }
        }
        cancel.setonclicklistener {
            if (popupwindow.isshowing) {
                popupwindow.dismiss()
            }
        }
    }
}