Android 流星效果的实现

     大晚上实在无聊，看着天空突然流星划过，心想，是不是也能在App上做出一个这个效果来 ，其实2年前当时用最简单的JavaScript实现过流星效果，于是乎今天也试着写了下，当时心想，网络上应该有相似的Demo，结果我并没有找到，真是一些下雪的例子，我下载过来看了一下，就是刷新View的操作，个人感觉这样做不妥，于是考虑使用SurfaceView实现

     SurfaceView的使用我就不介绍了，百度一大把

    直接看代码吧   理解起来也很简单  只有一个View

     

   demo下载地址   http://download.csdn.net/detail/u010192548/9546043

      

package itxwy.vacationdemo;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.WindowManager;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

/**
* 绘画View
* author True Lies
* Created by Administrator on 2016/6/11.
*/
public class MeteorView extends SurfaceView
implements
SurfaceHolder.Callback {

private SurfaceHolder mSurfaceHolder = null;
private boolean isThreadOpen = false;
private Bitmap mMeteorBmp = null;
private List<MeteorAddressModule> mMeteorAddressModuleArray = new ArrayList<MeteorAddressModule>();

private Random mRandom = new Random();
private Paint mPaint = new Paint();

public MeteorView(Context context) {
this(context, null);
}

public MeteorView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}

public MeteorView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}

private void init(Context mContext) {

WindowManager windowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics displayMetrics = new DisplayMetrics();
windowManager.getDefaultDisplay().getMetrics(displayMetrics);
App.SCREEN_WIDTH = displayMetrics.widthPixels;
App.SCREEN_HEIGHT = displayMetrics.heightPixels;

mSurfaceHolder = getHolder();
mSurfaceHolder.addCallback(this);//事件添加

}

private class DrawThread extends Thread {
private SurfaceHolder mSurfaceHolder;
public boolean isRun;
public DrawThread(SurfaceHolder holder) {
this.mSurfaceHolder = holder;
isRun = true;
for (int i = 0; i < 10; i++) {
float mX = mRandom.nextInt(App.SCREEN_WIDTH);
float mY = mRandom.nextInt(500);
MeteorAddressModule meteorAddressModule = new MeteorAddressModule();
meteorAddressModule.setmX(mX);
meteorAddressModule.setmY(mY);
mMeteorAddressModuleArray.add(meteorAddressModule);
}
}

@Override
public void run() {
Canvas mCanvas = null;
while (isRun) {

try {
synchronized (mSurfaceHolder) {
mCanvas = mSurfaceHolder.lockCanvas();
//下面三句段代码  重置画板的作用 先清除xfermode对象再设置
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
mCanvas.drawPaint(mPaint);
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
for (int i = 0; i < mMeteorAddressModuleArray.size(); i++) {
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.mipmap.meteor);
MeteorAddressModule meteorAddressModule = mMeteorAddressModuleArray.get(i);
meteorAddressModule.setmX(meteorAddressModule.getmX()-5);
meteorAddressModule.setmY(meteorAddressModule.getmY()+5);
System.out.println(meteorAddressModule.getmX()+"x");
System.out.println(meteorAddressModule.getmY()+"y");
mCanvas.drawBitmap(bitmap, meteorAddressModule.getmX(), meteorAddressModule.getmY(), mPaint);
if(meteorAddressModule.getmX()<0||meteorAddressModule.getmY()>App.SCREEN_HEIGHT){
if(!bitmap.isRecycled()){
bitmap.recycle();
}
mMeteorAddressModuleArray.remove(meteorAddressModule);
}
}
if(mMeteorAddressModuleArray.size()<=0){
isRun = false;
}
}

} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
} finally {
if(mCanvas!=null){
mSurfaceHolder.unlockCanvasAndPost(mCanvas);
}
}

}
}
}

//绘画事件
@Override
public void surfaceCreated(SurfaceHolder holder) {//surface创建的时候
DrawThread  mDrawThread = new DrawThread(mSurfaceHolder);
mDrawThread.start();

isThreadOpen = true;
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {//surfaceView改变的时候

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {//surfaceView销毁的时候
isThreadOpen = false;
}