弹出对话框输入框

需求：

屏幕中间弹出一个对话框，动画效果从中间伸展放大，背景变暗，消失向中间缩小，背景变亮

private void showAddStudentDialog() {
    View addStudentView = LayoutInflater.from(this).inflate(R.layout.add_student_dialog, null);
    final PopupWindow popupWindow = new PopupWindow(addStudentView, DensityHelp.dip2px(this, 306), DensityHelp.dip2px(this, 280));
    popupWindow.setOutsideTouchable(true);
    popupWindow.setFocusable(true);
    popupWindow.setBackgroundDrawable(new BitmapDrawable());
    popupWindow.setAnimationStyle(R.style.add_student_dialog);
    popupWindow.showAtLocation(addStudentView, Gravity.CENTER, 0, 0);
    setWindowBgColor(0.5f);
    ImageView close = (ImageView) addStudentView.findViewById(R.id.close);
    close.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            popupWindow.dismiss();
        }
    });
    popupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() {
        @Override
        public void onDismiss() {
            setWindowBgColor(1f);
        }
    });
}

private void setWindowBgColor(float alpha) {
    WindowManager.LayoutParams params = getWindow().getAttributes();
    params.alpha = alpha;
    getWindow().setAttributes(params);
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="306dp"
    android:layout_height="280dp"
    android:background="@color/white"
    android:orientation="vertical">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="52dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="新增学员"
            android:textColor="@color/c333333"
            android:textSize="16sp" />

        <ImageView
            android:id="@+id/close"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_alignParentRight="true"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:src="@drawable/btn_close_gray" />
    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="0.5dp"
        android:background="@color/cF2F2F2" />

    <EditText
        android:id="@+id/userName"
        android:layout_width="match_parent"
        android:layout_height="44dp"
        android:layout_marginLeft="15dp"
        android:layout_marginRight="15dp"
        android:layout_marginTop="15dp"
        android:background="@drawable/usual_student_bg"
        android:ellipsize="end"
        android:hint="学员姓名"
        android:paddingLeft="12dp"
        android:paddingRight="12dp"
        android:singleLine="true"
        android:textColor="@color/c333333"
        android:textColorHint="@color/c999999"
        android:textSize="14sp"
        tools:text="姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名" />

    <EditText
        android:id="@+id/phone"
        android:layout_width="match_parent"
        android:layout_height="44dp"
        android:layout_marginLeft="15dp"
        android:layout_marginRight="15dp"
        android:layout_marginTop="10dp"
        android:background="@drawable/usual_student_bg"
        android:ellipsize="end"
        android:hint="手机号"
        android:paddingLeft="12dp"
        android:paddingRight="12dp"
        android:singleLine="true"
        android:textColor="@color/c333333"
        android:textColorHint="@color/c999999"
        android:textSize="14sp"
        tools:text="姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名姓名" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="20dp"
        android:text="请确定后填写，提交后将不能修改"
        android:textColor="@color/c999999"
        android:textSize="14sp" />

    <Button
        android:id="@+id/submit"
        android:layout_width="match_parent"
        android:layout_height="44dp"
        android:layout_marginBottom="20dp"
        android:layout_marginLeft="15dp"
        android:layout_marginRight="15dp"
        android:layout_marginTop="10dp"
        android:background="@color/ce62233"
        android:text="确认提交"
        android:textColor="@color/white"
        android:textSize="16sp" />
</LinearLayout>

<style name="add_student_dialog">
    <item name="android:windowEnterAnimation">@anim/add_student_dialog_in</item>
    <item name="android:windowExitAnimation">@anim/add_student_dialog_out</item>
</style>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <scale
        android:duration="100"
        android:fromXScale="0"
        android:fromYScale="0"
        android:pivotX="50%"
        android:pivotY="50%"
        android:toXScale="1"
        android:toYScale="1" />
</set>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <scale
        android:duration="100"
        android:fromXScale="1"
        android:fromYScale="1"
        android:pivotX="50%"
        android:pivotY="50%"
        android:toXScale="0"
        android:toYScale="0" />
</set>