本文实例讲述了Android实现带有边框的ListView和item的方法。分享给大家供大家参考，具体如下：
想为ListView和item四周添加边框有两种方法：
1.贴一张带有边框效果的背景图
2.自定义Draw的方法
第一种方法较第二种方法更耗系统资源，但是用法简单，只需要一张图设置为相应控件的背景即可，而第二种灵活性好些。
这次是实现带有边框的ListView和item，为此写个简单Demo 学习学习
先看下Demo运行效果吧
下面是主要代码，主要是用到Canvas.drawLine(...)代码简单，我就不啰嗦了
BorderListView.Java
package com.borderlistview.manymore13; import android.content.Context; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.DashPathEffect; import android.graphics.Paint; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.widget.ListView; public class BorderListView extends ListView{ public BorderListView(Context context) { super(context); } public BorderListView(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onDraw(Canvas canvas) { float width = getWidth(); float height= getHeight(); int lineWidth = 10; // 线宽十个像素 int grayColor = Color.GRAY; Paint mLinePaint = new Paint(); mLinePaint.setColor(grayColor); mLinePaint.setStyle(Paint.Style.STROKE); mLinePaint.setAntiAlias(true); mLinePaint.setStrokeWidth(lineWidth); // 画四周的边框 注意下面的 lineWidth/2 不加的话四周的线可能不一样粗 canvas.drawLine(0f, 0+lineWidth/2, width, 0+lineWidth/2, mLinePaint); canvas.drawLine(width-lineWidth/2, 0, width-lineWidth/2, height, mLinePaint); canvas.drawLine(width-lineWidth/2, height-lineWidth/2, 0, height-lineWidth/2, mLinePaint); canvas.drawLine(0+lineWidth/2, height, 0+lineWidth/2, 0,mLinePaint); super.onDraw(canvas); } }
ListViewItem.java ListView的item 添加虚线和红线
package com.borderlistview.manymore13; import com.manymore13.MyListview.R; import android.content.Context; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.DashPathEffect; import android.graphics.Paint; import android.view.LayoutInflater; import android.view.View; import android.widget.FrameLayout; import android.widget.RelativeLayout; import android.widget.TextView; public class ListViewItem extends RelativeLayout{ private View viewHolder; private TextView tvEventName; private Context c; private FrameLayout leftFrame; public ListViewItem(Context context) { super(context); LayoutInflater flater = LayoutInflater.from(context); viewHolder = flater.inflate(R.layout.item, this); getViewAndSetClick(); c = context; } private void getViewAndSetClick() { tvEventName = (TextView)viewHolder.findViewById(R.id.eventName); leftFrame = (FrameLayout)viewHolder.findViewById(R.id.frame); } public void setEventName(String name) { tvEventName.setText(name); } public void updateView() { this.postInvalidate(); } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); Resources res = getResources(); int grayColor = Color.GRAY; int redColor = res.getColor(R.color.red); int leftFramepos = leftFrame.getRight(); Paint mLinePaint = new Paint(); mLinePaint.setColor(redColor); mLinePaint.setStyle(Paint.Style.STROKE); mLinePaint.setStrokeWidth(2); //画两条直线 canvas.drawLine(leftFramepos+20, 0f, leftFramepos+20, getHeight(), mLinePaint); canvas.drawLine(leftFramepos+25, 0f, leftFramepos+25, getHeight(), mLinePaint); // 画虚线 mLinePaint.setColor(grayColor); DashPathEffect effect = new DashPathEffect(new float[] { 5,5, 5, 5, 5}, 3); mLinePaint.setAntiAlias(true); mLinePaint.setPathEffect(effect); canvas.drawLine(0, getHeight(), getWidth(), getHeight(), mLinePaint); } }
MyBaseAdaper.java
package com.borderlistview.manymore13; import java.util.List; import android.content.Context; import android.os.Handler; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.WindowManager; import android.widget.BaseAdapter; import android.widget.ImageView; public class MyBaseAdaper extends BaseAdapter{ private List<String> list; private Context c; MyBaseAdaper(Context c, List<String> list) { this.list = list; this.c = c; } @Override public int getCount() { // TODO Auto-generated method stub return list.size(); } @Override public Object getItem(int i) { // TODO Auto-generated method stub return list.get(i); } @Override public long getItemId(int i) { // TODO Auto-generated method stub return i; } @Override public View getView(int i, View view, ViewGroup viewgroup) { ListViewItem itemView = null ; if(view == null){ itemView = new ListViewItem(c); }else{ itemView = (ListViewItem)view; } itemView.setEventName(list.get(i)); return itemView; } }
另外，在写本次Demo的时候报了错误，有错就改 Caused by: java.lang.NoSuchMethodException:BorderListView(Context,AttributeSet)
在 BorderListView类中加一个构造函数 搞定
public BorderListView(Context context, AttributeSet attrs) { super(context, attrs); }
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