android自定义listview实现圆角
在项目中我们会经常遇到这种圆角效果,因为直角的看起来确实不那么雅观,可能大家会想到用图片实现,试想上中下要分别做三张图片,这样既会是自己的项目增大也会增加内存使用量,所以使用shape来实现不失为一种更好的实现方式。在这里先看一下shape的使用:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <!-- 渐变 --> <gradient android:startColor="#B5E7B8" android:endColor="#76D37B" android:angle="270" /> <!-- 描边 --> <stroke android:width="1dip" android:color="@color/blue" /> <!-- 实心 --> <solid android:color="#FFeaeaea" /> <!-- 圆角 --> <corners android:bottomRightRadius="4dip" android:bottomLeftRadius="4dip" android:topLeftRadius="4dip" android:topRightRadius="4dip" /> </shape>
solid:实心,就是填充的意思
android:color指定填充的颜色
gradient:渐变
android:startColor和android:endColor分别为起始和结束颜色,ndroid:angle是渐变角度,必须为45的整数倍。
另外渐变默认的模式为android:type="linear",即线性渐变,可以指定渐变为径向渐变,android:type="radial",径向渐变需要指定半径android:gradientRadius="50"。
stroke:描边
android:width="2dp" 描边的宽度,android:color 描边的颜色。
我们还可以把描边弄成虚线的形式,设置方式为:
android:dashWidth="5dp"
android:dashGap="3dp"
其中android:dashWidth表示'-'这样一个横线的宽度,android:dashGap表示之间隔开的距离。
corners:圆角
android:radius为角的弧度,值越大角越圆。
OK,下面开始自定义listview实现圆角的例子:
首先在drawable下定义只有一项的选择器app_list_corner_round.xml:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <!-- 渐变 --> <gradient android:startColor="#B5E7B8" android:endColor="#76D37B" android:angle="270" /> <!-- 描边 --> <stroke android:width="1dip" android:color="@color/blue" /> <!-- 实心 --> <solid android:color="#FFeaeaea" /> <!-- 圆角 --> <corners android:bottomRightRadius="4dip" android:bottomLeftRadius="4dip" android:topLeftRadius="4dip" android:topRightRadius="4dip" /> </shape>
如果是顶部第一项,则上面两个角为圆角,app_list_corner_round_top.xml:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <gradient android:startColor="#B5E7B8" android:endColor="#76D37B" android:angle="270" /> <stroke android:width="1dip" android:color="@color/blue" /> <solid android:color="#FFeaeaea" /> <corners android:topLeftRadius="4dip" android:topRightRadius="4dip" /> </shape>
如果是底部最后一项,则下面两个角为圆角,app_list_corner_round_bottom.xml:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <gradient android:startColor="#B5E7B8" android:endColor="#76D37B" android:angle="270" /> <stroke android:width="1dip" android:color="@color/blue" /> <solid android:color="#FFeaeaea" /> <corners android:bottomRightRadius="4dip" android:bottomLeftRadius="4dip" /> </shape>
如果是中间项,则应该不需要圆角, app_list_corner_round_center.xml:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" > <gradient android:startColor="#B5E7B8" android:endColor="#76D37B" android:angle="270" /> <stroke android:width="1dip" android:color="@color/blue" /> <solid android:color="#FFeaeaea" />
<corners android:bottomRightRadius="4dip" android:bottomLeftRadius="4dip" /> </shape>
listview的背景图片大家可以使用stroke描述,这里我使用了一张9PNG的图片,因为9PNG图片拉伸不失真。
定义好了圆角的shape接下来是自定义listview的实现:
package cn.com.karl.view; import cn.com.karl.test.R; import android.content.Context; import android.util.AttributeSet; import android.view.MotionEvent; import android.widget.AdapterView; import android.widget.ListView; /** * 圆角ListView */ public class CornerListView extends ListView { public CornerListView(Context context) { super(context); } public CornerListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } public CornerListView(Context context, AttributeSet attrs) { super(context, attrs); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: int x = (int) ev.getX(); int y = (int) ev.getY(); int itemnum = pointToPosition(x, y); if (itemnum == AdapterView.INVALID_POSITION) break; else { if (itemnum == 0) { if (itemnum == (getAdapter().getCount() - 1)) { //只有一项 setSelector(R.drawable.app_list_corner_round); } else { //第一项 setSelector(R.drawable.app_list_corner_round_top); } } else if (itemnum == (getAdapter().getCount() - 1)) //最后一项 setSelector(R.drawable.app_list_corner_round_bottom); else { //中间项 setSelector(R.drawable.app_list_corner_round_center); } } break; case MotionEvent.ACTION_UP: break; } return super.onInterceptTouchEvent(ev); } }
下面看一下列表布局文件setting。xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <include layout="@layout/head" /> <cn.com.karl.view.CornerListView android:id="@+id/setting_list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_margin="10dip" android:background="@drawable/corner_list_bg" android:cacheColorHint="#00000000" /> </LinearLayout>
自定义Listview对应的item文件 main_tab_setting_list_item.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content"> <RelativeLayout android:layout_width="fill_parent" android:layout_height="50dp" android:gravity="center_horizontal"> <TextView android:id="@+id/tv_system_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_centerVertical="true" android:layout_marginLeft="10dp" android:text="分享" android:textColor="@color/black"/> <ImageView android:id="@+id/iv_system_right" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_centerVertical="true" android:layout_marginRight="10dp" android:src="@drawable/arrow1" /> </RelativeLayout> </LinearLayout>
最后是在activity中填充适配器:
package cn.com.karl.test; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import cn.com.karl.view.CornerListView; import android.os.Bundle; import android.view.View; import android.widget.SimpleAdapter; public class SettingActivity extends BaseActivity { private CornerListView cornerListView = null; private List<Map<String, String>> listData = null; private SimpleAdapter adapter = null; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.setting); cornerListView = (CornerListView)findViewById(R.id.setting_list); setListData(); adapter = new SimpleAdapter(getApplicationContext(), listData, R.layout.main_tab_setting_list_item , new String[]{"text"}, new int[]{R.id.tv_system_title}); cornerListView.setAdapter(adapter); initHead(); btn_leftTop.setVisibility(View.INVISIBLE); tv_head.setText("设置"); } /** * 设置列表数据 */ private void setListData(){ listData = new ArrayList<Map<String,String>>(); Map<String,String> map = new HashMap<String, String>(); map.put("text", "分享"); listData.add(map); map = new HashMap<String, String>(); map.put("text", "检查新版本"); listData.add(map); map = new HashMap<String, String>(); map.put("text", "反馈意见"); listData.add(map); map = new HashMap<String, String>(); map.put("text", "关于我们"); listData.add(map); map = new HashMap<String, String>(); map.put("text", "支持我们,请点击这里的广告"); listData.add(map); } }
这样就完成了,虽然过程较繁杂,但是当做一个好的模板以后使用会方便很多,最后看一下实现效果和我们用图片实现的一样吗
【常用按钮style】
<?xml version="1.0" encoding="utf-8"?> <layer-list xmlns:android="http://schemas.android.com/apk/res/android"> <item> <shape> <gradient android:angle="270" android:endColor="#d86212" android:startColor="#f9c468" /> <stroke android:color="#ce5b18" android:width="1dp"/> <corners android:radius="5dip" /> </shape> </item> <item> <selector> <item android:state_pressed="true"> <shape> <solid android:color="#dbdbdb" /> <corners android:radius="5dip" /> </shape> </item> </selector> </item> </layer-list>