Android之shape与selector实现圆角

shape和selector是Android UI设计中经常用到的，比如我们要自定义一个圆角Button，点击Button有些效果的变化，就要用到shape和selector。可以这样说，shape和selector在美化控件中的作用是至关重要的。

1.Shape

简介

作用：XML中定义的几何形状

位置：res/drawable/文件的名称.xml

使用的方法：

Java代码中：R.drawable.文件的名称

XML中：android:background="@drawable/文件的名称"

属性：

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<shape>  android:shape=["rectangle" | "oval" | "line" | "ring"]  

  

其中rectagle矩形，oval椭圆，line水平直线，ring环形  

  

<shape>中子节点的常用属性：  

  

<gradient>  渐变  

  

android:startColor  起始颜色  

  

android:endColor  结束颜色               

  

android:angle  渐变角度，0从上到下，90表示从左到右，数值为45的整数倍默认为0；  

  

android:type  渐变的样式 liner线性渐变 radial环形渐变 sweep  

  

<solid >  填充  

  

android:color  填充的颜色  

  

<stroke > 描边  

  

android:width 描边的宽度  

  

android:color 描边的颜色  

  

android:dashWidth 表示'-'横线的宽度  

  

android:dashGap 表示'-'横线之间的距离  

  

<corners > 圆角  

  

android:radius  圆角的半径 值越大角越圆  

  

android:topRightRadius  右上圆角半径  

    

android:bottomLeftRadius 右下圆角角半径  

   

android:topLeftRadius 左上圆角半径  

  

android:bottomRightRadius 左下圆角半径  

2.Selector

 简介

位置：res/drawable/文件的名称.xml

使用的方法：

Java代码中：R.drawable.文件的名称

XML中：android:background="@drawable/文件的名称"

selector.xml

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<?xml version="1.0" encoding="utf-8"?>   

    <selector xmlns:android="http://schemas.android.com/apk/res/android">   

       

        <item android:state_selected="true">   

            <shape>   

                <gradient android:angle="270" android:endColor="#99BD4C"   

                    android:startColor="#A5D245" />   

                <size android:height="60dp" android:width="320dp" />   

                <corners android:radius="8dp" />   

            </shape>   

        </item>   

        <item android:state_pressed="true">   

            <shape>   

                <gradient android:angle="270" android:endColor="#99BD4C"   

                    android:startColor="#A5D245"/>   

                <size android:height="60dp" android:width="320dp" />   

                <corners android:radius="8dp" />   

            </shape>   

        </item>   

        <item>   

            <shape>   

                <gradient android:angle="270" android:endColor="#A8C3B0"   

                    android:startColor="#C6CFCE"/>   

                <size android:height="60dp" android:width="320dp" />   

                <corners android:radius="8dp" />   

            </shape>   

        </item>   

    </selector>  

list_item.xml

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<?xml version="1.0" encoding="utf-8"?>   

       <LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"   

        android:orientation="horizontal"     

        android:layout_width="fill_parent"      

        android:layout_height="wrap_content"   

        android:background="@drawable/selector"   

        >                       

        <ImageView     

            android:id="@+id/img"      

            android:layout_width="wrap_content"     

            android:layout_height="wrap_content"                

            android:layout_gravity="center_vertical"   

            android:layout_marginLeft="20dp"            

            />                              

            <TextView     

                android:text="data"     

                android:id="@+id/title"   

                android:layout_width="fill_parent"     

                android:layout_height="wrap_content"     

                android:gravity="center_vertical"      

                android:layout_marginLeft="20dp"     

                android:layout_marginTop="20dp"     

                android:textSize="14sp"                             

                android:textStyle="bold"   

                android:textColor="@color/black"                            

                >   

            </TextView>             

     </LinearLayout>  

main.xml

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<?xml version="1.0" encoding="utf-8"?>   

        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   

            android:orientation="vertical"     

            android:layout_width="fill_parent"      

            android:layout_height="wrap_content"   

            android:background="#253853"   

            >                                   

            <ListView     

              android:id="@+id/list"     

              android:layout_width="match_parent"     

              android:layout_height="match_parent"   

              android:cacheColorHint="#00000000"   

              android:divider="#2A4562"   

              android:dividerHeight="3px"   

              android:listSelector="#264365"   

              android:drawSelectorOnTop="false"    

              >   

            </ListView>     

    </LinearLayout>  

colors.xml

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<?xml version="1.0" encoding="utf-8"?>   

    <resources>   

        <color name="white">#FFFFFFFF</color>   

        <color name="transparency">#00000000</color>   

        <color name="title_bg">#1C86EE</color>   

        <color name="end_color">#A0cfef83</color>   

        <color name="black">#464646</color>   

    </resources>  

MainActivity

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package com.lingdududu.customlist;    

       

    import java.util.ArrayList;    

    import java.util.HashMap;    

       

    import xb.customlist.R;    

       

    import android.R.array;    

    import android.app.Activity;    

    import android.os.Bundle;    

    import android.widget.ArrayAdapter;    

    import android.widget.ListView;    

    import android.widget.SimpleAdapter;    

       

    public class MainActivity extends Activity {    

        ListView list;    

            

        String data[] = new String[]{    

                "China","UK","USA","Japan","German","Canada","ET","Narotu"      

        };    

            

            

         

        @Override   

        public void onCreate(Bundle savedInstanceState) {    

            super.onCreate(savedInstanceState);    

            setContentView(R.layout.main);    

                

                

            list =(ListView) findViewById(R.id.list);            

                

            SimpleAdapter adapter = new SimpleAdapter(this, getData(), R.layout.list_item,     

                    new String[]{"title","img"}, new int[]{R.id.title,R.id.img});    

                

            list.setAdapter(adapter);            

        }    

            

        private ArrayList<HashMap<String, Object>> getData() {          

            ArrayList<HashMap<String, Object>> dlist = new ArrayList<HashMap<String,Object>>();    

                

            for(int i =0;i<data.length;i++){    

                HashMap<String, Object>map = new HashMap<String, Object>();             

                map.put("title", data[i]);    

                map.put("img", R.drawable.item_left2);    

                dlist.add(map);     

            }    

            return dlist;    

        }    

    }  

效果图：