ImageSwitcher 图片切换器

<?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="match_parent"

    android:gravity="center_horizontal">

    <!-- 定义一个GridView组件 -->

    <GridView

        android:id="@+id/grid01"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:horizontalSpacing="2dp"

        android:verticalSpacing="2dp"

        android:numColumns="4"

        android:gravity="center"/>

    <!-- 定义一个ImageSwitcher组件 -->

    <ImageSwitcher android:id="@+id/switcher"

        android:layout_width="300dp"

        android:layout_height="300dp"

        android:layout_gravity="center_horizontal"

        android:inAnimation="@android:anim/fade_in"

        android:outAnimation="@android:anim/fade_out"/>

</LinearLayout>

主界面

package com.example.viewswitcher

import android.app.Activity

import android.os.Bundle

import android.view.View

import android.view.ViewGroup.LayoutParams

import android.widget.*

import android.widget.ViewSwitcher.ViewFactory

import android.widget.AdapterView.OnItemClickListener

import android.widget.AdapterView.OnItemSelectedListener

class MainActivity : Activity()

{

    internal var imageIds = intArrayOf(R.drawable.bomb5, R.drawable.bomb6,

        R.drawable.bomb7, R.drawable.bomb8, R.drawable.bomb9,

        R.drawable.bomb10, R.drawable.bomb11, R.drawable.bomb12,

        R.drawable.bomb13, R.drawable.bomb14, R.drawable.bomb15,

        R.drawable.bomb16)

    override fun onCreate(savedInstanceState: Bundle?)

    {

        super.onCreate(savedInstanceState)

        setContentView(R.layout.activity_main)

        // 创建一个List对象，List对象的元素是Map

        val listItems = ArrayList<Map<String, Any>>()

        for (i in imageIds.indices)

        {

            val listItem = HashMap<String, Any>()

            listItem["image"] = imageIds[i]

            listItems.add(listItem)

        }

        // 获取显示图片的ImageSwitcher

        val switcher = findViewById<ImageSwitcher>(R.id.switcher)

        // 为ImageSwitcher设置图片切换的动画效果

        // 使用Lambda表达式创建ViewFactory，表达式是makeView方法()的方法体

        switcher.setFactory    {

            // 创建ImageView对象

            val imageView = ImageView(this@MainActivity)

            imageView.scaleType = ImageView.ScaleType.FIT_CENTER

            imageView.layoutParams = FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT,

                LayoutParams.WRAP_CONTENT)

            // 返回ImageView对象

            imageView

        }

        // 创建一个SimpleAdapter

        val simpleAdapter = SimpleAdapter(this, listItems, R.layout.cell,

            arrayOf("image"), intArrayOf(R.id.image1)) // 使用/layout/cell.xml文件作为界面布局

        val grid = findViewById<GridView>(R.id.grid01)

        // 为GridView设置Adapter

        grid.adapter = simpleAdapter

        // 添加列表项被选中的监听器

        grid.onItemSelectedListener = object : OnItemSelectedListener

        {

            override fun onItemSelected(parent: AdapterView<*>, view: View, position: Int, id: Long)

            {

                // 显示当前被选中的图片

                switcher.setImageResource(imageIds[position])

            }

            override fun onNothingSelected(parent: AdapterView<*>)

            {

            }

        }

        // 添加列表项被单击的监听器

        grid.setOnItemClickListener {parent, view, position, id ->

            // 显示被单击的图片

            switcher.setImageResource(imageIds[position])

        }

    }

}

主程序