class BlankFragment : Fragment() {
    var ctx:Context? = null
    var mPosition:Int = 0
    var mInageId:Int = 0
    var mDesc:String = ""
    var title:String = ""

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        ctx = activity
        if (arguments != null) {
            mPosition = arguments!!.getInt("position", 0)
            mInageId = arguments!!.getInt("image_id", 0)
            mDesc = arguments!!.getString("desc")
            title = arguments!!.getString("title")
        }
        val view = inflater.inflate(R.layout.item, container, false)

        val pic:ImageView = view.findViewById(R.id.imageView)
        val desc:TextView = view.findViewById(R.id.textView)

        pic.setImageResource(mInageId)
        desc.text = mDesc
        return view
    }

    companion object {
        fun newInstance(position:Int, image_id:Int, desc:String, title:String) : BlankFragment {
            val fragment = BlankFragment()
            val bundle = Bundle()
            bundle.putInt("position", position)
            bundle.putInt("image_id", image_id)
            bundle.putString("desc", desc)
            bundle.putString("title", title)
            fragment.arguments = bundle
            return fragment
        }
    }
}

alert("对话框内容", "对话框标题") {
    positiveButton("确认") {
        //点按确认后执行的操作
    }
    negativeButton("取消") {
        //点按取消后执行的操作
    }
}.show()

class ImagePagerAdapter(val context: Context, val itemList:MutableList<itemInfo>) : PagerAdapter() {
    val views = mutableListOf<ImageView>()
    init {
        for (item in itemList) {
            val view = ImageView(context)
            //view.layoutParams = ActionBar.LayoutParams(ActionBar.LayoutParams.MATCH_PARENT, ActionBar.LayoutParams.WRAP_CONTENT)
            view.layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)

            view.setImageResource(item.pic)
            view.scaleType = ImageView.ScaleType.FIT_CENTER
            views.add(view)
        }
    }
    override fun isViewFromObject(p0: View, p1: Any): Boolean = (p0 === p1)

    override fun getCount(): Int = views.size

    override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
        container.removeView(views[position])
    }

    override fun instantiateItem(container: ViewGroup, position: Int): Any {
        container.addView(views[position])
        return views[position]
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return itemList[position].desc
    }//与PagerTabStrip或配合使用

}

class MainActivity : AppCompatActivity(), ViewPager.OnPageChangeListener {
    override fun onPageScrollStateChanged(p0: Int) {
    }

    override fun onPageScrolled(p0: Int, p1: Float, p2: Int) {

    }


    override fun onPageSelected(p0: Int) {
        Toast.makeText(this, p0.toString(), Toast.LENGTH_SHORT).show()
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //supportActionBar?.hide()
        var vp:ViewPager = findViewById(R.id.vp)
        val pics = arrayOf(R.mipmap.basic, R.mipmap.close, R.mipmap.debug, R.mipmap.edit)
        val list:MutableList<itemInfo> = mutableListOf()
        for (i in pics.indices) {
            list.add(itemInfo((i+1).toString(), pics[i]))
        }
        vp.adapter = ImagePagerAdapter(this, list)
        vp.currentItem = 0
        vp.addOnPageChangeListener(this)

        var title: PagerTabStrip = findViewById(R.id.title)

        title.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20f)
        title.setTextColor(Color.RED)
    }
}

btn.setOnClickListener ((View v) -> {
    toast("click")
})
btn.setOnclickListener {
    toast("click")
}
btn.setOnLongClickListener {
    toast("Long Click")
    true//lambdda的返回值，不写return
}
{a:Int, b:String -> String 
    (a +  b.toDouble()).toString()
}

{a:Int, b:String, c:Long/*输入参数列表*/ -> String/*返回值类型*/
    /*lambda body*/
    var temp:Double = a + b.toDouble()
    if (c == 0L) {
        "error"
    } else {
        (temp.toDouble() + c).toString()
    }//返回值(不要写return)
}

fun mathodName(/*para list*/) : String/*return value type*/ {
    /*
        function body
    */
}

fun TextView.println(str:CharSequence) {
    append("\n${str}")
}
fun TextView.print(str:CharSequence) {
    append(str)
}//这个东西是扩展函数，后面说
fun func(str:String = "哈哈哈",i:Int, j:Double) {//str的默认参数"哈哈哈"
    val text:TextView = findViewById(R.id.text)
    text.print("$str")
    text.println("$i")
    text.println("$j")
}

var integer:Int//一般用法var/val + 标识符 + : + 类型名，var表示变量
val integer1:Int = 0//val表示常量，相当于java中的final，c++中的const
var str = "this is a string"
//没有":String"，此时只要保证编译器可以知道变量的类型，则编译器可以完成类型推断
var flt:Float = 5f//f表示数据为float类型
var tobar:Toolbar? = findViewById<Toolbar>(R.id.toolbar)
/*
类型名后+'?'表示该变量为可空变量，kotlin为了防止java中NullPointerException，
默认所有的变量都是不可空（不能为null的），如果要让变量为空，需要+'?'，
此时，编译器会强制程序员对所有可空变量进行非空判断
*/

class Animal (type:String = "动物", name:String) {
    //没有@JvmOverloads修饰，可以省略constructor
    //等价以下写法
//class Animal constructor(type:String = "动物", name:String) {
    var Type:String = ""
    var Name:String = ""
    var Age:Int = 0
    var Sex:String = ""
    init {
        Type = type
        Name = name
    }
    constructor(type:String = "动物", name:String, age:Int, sex:String) : this(type, name){
        Age = age
        Sex = sex
    }

}

button.setOnClickListener {
    if (flag) {
        text.text = "I love you, at the first sight of you."
    } else {
        text.text = "I love three things in this world.Sun, moon and you. " +
                "Sun for morning, moon for night, and you forever."
    }
}