Android实现带有边框的ListView和item Android实现带有边框的ListView和item的方法

时间:2021-03-22 manymore13 人气:0

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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);
}

希望本文所述对大家Android程序设计有所帮助。

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