android中使用下拉列表、图像按钮时的常见问题

北京信息职业技术学院|范美英Android中使用下拉列表、图像按钮时的常见问题问题描述1如何实现点击图像按钮时显示类似左右图所示的效果？Android中使用下拉列表、图像按钮时的常见问题|问题描述问题解决方案1思路介绍：在Java中为图片按钮增加触摸监听的函数来实现图片切换。具体地，当图片按下时，修改按钮的背景图片，当抬起时再修改为正常的图片显示，代码如左。Android中使用下拉列表、图像按钮时的常见问题|问题解决方案ImageButton

btn

=

(ImageButton)findViewById(R.id.imageButton1);

btn.setOnTouchListener(new

View.OnTouchListener(){

public

boolean

onTouch(View

v,

MotionEvent

event)

{

if(event.getAction()

==

MotionEvent.ACTION_DOWN){

//重新设置按下时的背景图片

((ImageButton)v).setImageDrawable(getResources().getDrawable(R.drawable.android_btn_pressed));

}else

if(event.getAction()

==

MotionEvent.ACTION_UP){

//再修改为抬起时的正常图片

((ImageButton)v).setImageDrawable(getResources().getDrawable(R.drawable.android_btn));

}

return

false;

}

});

问题解决方案2给按钮配置XML文件来实现图片按钮的背景切换步骤1：在layout或drawable文件夹下添加一个image_btn_press.xml文件，代码如左步骤2：在main.xml中设置图片按钮的属性，将上面的xml文件添加到图片按钮的background属性中，使用格式为：android:background="@layout/image_btn_press"Android中使用下拉列表、图像按钮时的常见问题|问题解决方案<?xml

version="1.0"

encoding="utf-8"?>

<selector

xmlns:android="/apk/res/android">

<item

android:state_pressed="false"

android:drawable="@drawable/android_btn"

/>

<item

android:state_focused="true"

android:drawable="@drawable/android_btn"

/>

<item

android:state_pressed="true"

android:drawable="@drawable/android_btn_pressed"

/>

</selector>

问题描述2如左图所示，如何实现下拉列表的联动？比如：当第1个下拉列表中选择北京时，第2个列表的数据自动设置为北京的各区县；当第2个下拉列表中选择东城区时，第3个列表的数据自动设置为东城区的各个子区；Android中使用下拉列表、图像按钮时的常见问题|问题描述问题解决方案1//预设省级选项值privateString[]province=newString[]{"北京","上海","天津","广东"};//,"重庆","黑龙江","江苏","山东","浙江","香港","澳门"};//预设地级选项值

privateString[][]city=newString[][]{

{"东城区","西城区","崇文区","宣武区","朝阳区","海淀区","丰台区","石景山区","门头沟区","房山区","通州区","顺义区","大兴区","昌平区","平谷区","怀柔区","密云县","延庆县"},{"长宁区","静安区","普陀区","闸北区","虹口区"},

{"和平区","河东区","河西区","南开区","河北区","红桥区","塘沽区","汉沽区","大港区","东丽区"},{"广州","深圳","韶关","珠海","汕头","佛山","湛江","肇庆","江门","茂名","惠州","梅州","汕尾","河源","阳江","清远","东莞","中山","潮州","揭阳","云浮"}Android中使用下拉列表、图像按钮时的常见问题|问题解决方案问题解决方案1 };//预设县级选项值

privateString[][][]county=newString[][][]{{//北京

{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"}},{//上海

{"无"},{"无"},{"无"},{"无"},{"无"}},{//天津

{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"},{"无"}},Android中使用下拉列表、图像按钮时的常见问题|问题解决方案问题解决方案1{//广东{"海珠区","荔湾区","越秀区","白云区","萝岗区","天河区","黄埔区","花都区","从化市","增城市","番禺区",沙区"},//广州

{"宝安区","福田区","龙岗区","罗湖区","南山区","盐田区"},//深圳{"武江区","浈江区","曲江区","乐昌市","南雄市","始兴县","仁化县","翁源县","新丰县","乳源县"}//韶关}};Android中使用下拉列表、图像按钮时的常见问题|问题解决方案问题解决方案1Android中使用下拉列表、图像按钮时的常见问题|问题解决方案逐级设置问题解决方案1Android中使用下拉列表、图像按钮时的常见问题|问题解决方案逐级