Android编程简单实现雷达扫描效果

本文实例讲述了android编程简单实现雷达扫描效果。分享给大家供大家参考，具体如下：

在eoe看到有一篇关于雷达扫描的文章，然后看了下，很简单，但是觉得还有很多可以优化的地方，下面贴出来

package com.example.wave;
import android.content.context;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.matrix;
import android.graphics.paint;
import android.graphics.paint.style;
import android.graphics.shader;
import android.graphics.sweepgradient;
import android.util.attributeset;
import android.widget.framelayout;
public class radarview extends framelayout {
 private int viewsize = 500;
 private paint mpaintline;
 private paint mpaintsector;
 private boolean isstart = false;
 private scanthread mthread;
 private int start = 0;
 private final int paintwidth = 10;
 public radarview(context context) {
  super(context);
  init();
 }
 public radarview(context context, attributeset attrs) {
  super(context, attrs);
  init();
 }
 private void init() {
  initpaint();
  mthread = new scanthread();
  setbackgroundcolor(color.transparent);
 }
 private void initpaint() {
  mpaintline = new paint();
  mpaintline.setstrokewidth(paintwidth);
  mpaintline.setantialias(true);
  mpaintline.setstyle(style.stroke);
  mpaintline.setcolor(0xffff0000);
  mpaintsector = new paint();
  mpaintsector.setcolor(0x9d00ff00);
  mpaintsector.setantialias(true);
 }
 public void setviewsize(int size) {
  this.viewsize = size;
  mshader = new sweepgradient(viewsize >> 1, viewsize >> 1, color.transparent, color.green);
  setmeasureddimension(viewsize, viewsize);
 }
 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  setmeasureddimension(viewsize, viewsize);
 }
 public void start() {
  mthread.start();
  isstart = true;
 }
 public void stop() {
  if (isstart) {
   thread.interrupted();
   isstart = false;
  }
 }
 private shader mshader = new sweepgradient(viewsize >> 1, viewsize >> 1, color.transparent, color.green);
 private matrix matrix = new matrix();
 @override
 protected void ondraw(canvas canvas) {
  super.ondraw(canvas);
  int halfradasize = viewsize >> 1;
  canvas.drawcircle(halfradasize, halfradasize, halfradasize >> 1, mpaintline);
  canvas.drawcircle(halfradasize, halfradasize, halfradasize - (paintwidth >> 1), mpaintline);
  canvas.drawline(halfradasize, 0, halfradasize, viewsize, mpaintline);
  canvas.drawline(0, halfradasize, viewsize, halfradasize, mpaintline);
  mpaintsector.setshader(mshader);
  canvas.concat(matrix);
  canvas.drawcircle(halfradasize, halfradasize, halfradasize - paintwidth, mpaintsector);
 }
 protected class scanthread extends thread {
  int halfradasize = viewsize >> 1;
  @override
  public void run() {
   while (isstart) {
    start = start + 2;
    matrix.reset();
    matrix.postrotate(start, halfradasize, halfradasize);
    postinvalidate();
    try {
     thread.sleep(10);
    } catch (interruptedexception e) {
     e.printstacktrace();
    }
   }
  }
 }
}

希望本文所述对大家android程序设计有所帮助。