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。
