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。