Android動(dòng)畫(huà)之雷達(dá)掃描效果

更新時(shí)間：2016年08月08日 10:34:53 作者：IAM四十二

雷達(dá)掃描效果在我們?nèi)粘?huì)經(jīng)?？吹剑热缭谛吕宋⒉┥嫌幸粋€(gè)雷達(dá)功能，感覺(jué)類(lèi)似于微信附近的人。只是多了一個(gè)類(lèi)似于雷達(dá)掃描效果的動(dòng)畫(huà)，某些知名安全軟件也有這樣的雷達(dá)效果，因此今天在這里小編帶著大家學(xué)習(xí)一下。

我們首先看一下效果圖，有個(gè)整體的印象

好了，為了便于理解，這里就按照動(dòng)畫(huà)所見(jiàn)內(nèi)容依次展開(kāi)來(lái)說(shuō)

準(zhǔn)備

這里決定采用canvas（畫(huà)布）和paint（畫(huà)筆）實(shí)現(xiàn)了這個(gè)簡(jiǎn)單動(dòng)畫(huà)控件。

由圖片可以看到有兩條交叉的十字線、幾個(gè)圓圈和一些白點(diǎn)，那么首先定義一下所需的畫(huà)筆，畫(huà)布及一些數(shù)據(jù)

  setBackgroundColor(Color.TRANSPARENT);

  //寬度=5，抗鋸齒，描邊效果的白色畫(huà)筆
  mPaintLine = new Paint();
  mPaintLine.setStrokeWidth(5);
  mPaintLine.setAntiAlias(true);
  mPaintLine.setStyle(Style.STROKE);
  mPaintLine.setColor(Color.WHITE);

  //寬度=5，抗鋸齒，描邊效果的淺綠色畫(huà)筆
  mPaintCircle = new Paint();
  mPaintCircle.setStrokeWidth(5);
  mPaintCircle.setAntiAlias(true);
  mPaintCircle.setStyle(Style.FILL);
  mPaintCircle.setColor(0x99000000);

  //暗綠色的畫(huà)筆
  mPaintSector = new Paint();
  mPaintSector.setColor(0x9D00ff00);
  mPaintSector.setAntiAlias(true);
  //定義一個(gè)暗綠色的梯度渲染
  mShader = new SweepGradient(viewSize / 2, viewSize / 2,
 Color.TRANSPARENT, Color.GREEN);
  mPaintSector.setShader(mShader);

  //白色實(shí)心畫(huà)筆
  mPaintPoint=new Paint();
  mPaintPoint.setColor(Color.WHITE);
  mPaintPoint.setStyle(Style.FILL);

  //隨機(jī)生成一些數(shù)組點(diǎn)，模擬雷達(dá)掃描結(jié)果
  point_x = UtilTools.Getrandomarray(15, 300);
  point_y = UtilTools.Getrandomarray(15, 300);

這里說(shuō)一下這個(gè)SweepGradient

SweepGradient的構(gòu)造函數(shù)：

public SweepGradient(float cx, float cy, int[] colors, float[] positions)

public SweepGradient(float cx, float cy, int color0, int color1)

其中cx,cy 指定圓心, color1,color0 或 colors 指定漸變的顏色，對(duì)于使用多于兩種顏色時(shí)，還可以通過(guò)positions 指定每種顏色的相對(duì)位置，positions 設(shè)為NULL時(shí)表示顏色均勻分布。

繪制基本圖形

  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintCircle);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 255, mPaintLine);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 125, mPaintLine);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintLine);
  //繪制兩條十字線
  canvas.drawLine(viewSize / 2, 0, viewSize / 2, viewSize, mPaintLine);
  canvas.drawLine(0, viewSize / 2, viewSize, viewSize / 2, mPaintLine);

這樣就繪制除了整個(gè)UI,接下來(lái)加上動(dòng)畫(huà)，就可以實(shí)現(xiàn)整體的效果。

動(dòng)畫(huà)實(shí)現(xiàn)

這里實(shí)現(xiàn)動(dòng)畫(huà)的時(shí)候，用到了Matrix這個(gè)東西，也就是矩陣。上學(xué)的時(shí)候，線性代數(shù)老師講各種線性變換時(shí)，腦子里在想，這玩意是干嘛使得，現(xiàn)在總算是遇上了，現(xiàn)在看起來(lái)也是云里霧里?？偟膩?lái)說(shuō)就是可以使用Matrix實(shí)現(xiàn)強(qiáng)大的圖形動(dòng)畫(huà)，包括位移、旋轉(zhuǎn)、縮放及透明變化等效果，matrix有著一系列的setTranslate,setRotate,setScale等方法。很方便的實(shí)現(xiàn)圖形各種變換，主要還是需要理解各種變換。

動(dòng)畫(huà)實(shí)現(xiàn)線程

 protected class ScanThread extends Thread {

  private RadarView view;

  public ScanThread(RadarView view) {
   // TODO Auto-generated constructor stub
   this.view = view;
  }

  @Override
  public void run() {
   // TODO Auto-generated method stub
   while (threadRunning) {
    if (isstart) {
     view.post(new Runnable() {
      public void run() {
       start = start + 1;
       matrix = new Matrix();
       //設(shè)定旋轉(zhuǎn)角度,制定進(jìn)行轉(zhuǎn)轉(zhuǎn)操作的圓心
//       matrix.postRotate(start, viewSize / 2, viewSize / 2);
//       matrix.setRotate(start,viewSize/2,viewSize/2);
       matrix.preRotate(direction*start,viewSize/2,viewSize/2);
       view.invalidate();

      }
     });
     try {
      Thread.sleep(5);
     } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }
   }
  }
 }

首先，這里在一個(gè)獨(dú)立線程中不斷的對(duì)start做累加，作為旋轉(zhuǎn)角度。然后將其和matrix關(guān)聯(lián)。這里嘗試使用了matrix的三個(gè)方法，暫時(shí)沒(méi)有發(fā)現(xiàn)區(qū)別。

動(dòng)畫(huà)繪制

接下來(lái)在onDraw方法中不斷繪制圖形即可

  //根據(jù)matrix中設(shè)定角度，不斷繪制shader,呈現(xiàn)出一種扇形掃描效果
  canvas.concat(matrix);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintSector);

最終實(shí)現(xiàn)

好了，最終整體的代碼如下：

public class RadarView extends FrameLayout {

 private Context mContext;
 private int viewSize = 800;
 private Paint mPaintLine;
 private Paint mPaintCircle;
 private Paint mPaintSector;
 public boolean isstart = false;
 private ScanThread mThread;
 private Paint mPaintPoint;
 //旋轉(zhuǎn)效果起始角度
 private int start = 0;

 private int[] point_x;
 private int[] point_y;

 private Shader mShader;

 private Matrix matrix;

 public final static int CLOCK_WISE=1;
 public final static int ANTI_CLOCK_WISE=-1;

 @IntDef({ CLOCK_WISE, ANTI_CLOCK_WISE })
 public @interface RADAR_DIRECTION {

 }
 //默認(rèn)為順時(shí)針呢
 private final static int DEFAULT_DIERCTION=CLOCK_WISE;

 //設(shè)定雷達(dá)掃描方向
 private int direction=DEFAULT_DIERCTION;

 private boolean threadRunning = true;

 public RadarView(Context context, AttributeSet attrs) {
  super(context, attrs);
  // TODO Auto-generated constructor stub
  mContext = context;
  initPaint();
 }

 public RadarView(Context context) {
  super(context);
  // TODO Auto-generated constructor stub
  mContext = context;
  initPaint();

 }

 private void initPaint() {
  // TODO Auto-generated method stub
  setBackgroundColor(Color.TRANSPARENT);

  //寬度=5，抗鋸齒，描邊效果的白色畫(huà)筆
  mPaintLine = new Paint();
  mPaintLine.setStrokeWidth(5);
  mPaintLine.setAntiAlias(true);
  mPaintLine.setStyle(Style.STROKE);
  mPaintLine.setColor(Color.WHITE);

  //寬度=5，抗鋸齒，描邊效果的淺綠色畫(huà)筆
  mPaintCircle = new Paint();
  mPaintCircle.setStrokeWidth(5);
  mPaintCircle.setAntiAlias(true);
  mPaintCircle.setStyle(Style.FILL);
  mPaintCircle.setColor(0x99000000);

  //暗綠色的畫(huà)筆
  mPaintSector = new Paint();
  mPaintSector.setColor(0x9D00ff00);
  mPaintSector.setAntiAlias(true);
  mShader = new SweepGradient(viewSize / 2, viewSize / 2, Color.TRANSPARENT, Color.GREEN);
  mPaintSector.setShader(mShader);

  //白色實(shí)心畫(huà)筆
  mPaintPoint=new Paint();
  mPaintPoint.setColor(Color.WHITE);
  mPaintPoint.setStyle(Style.FILL);

  //隨機(jī)生成的點(diǎn)，模擬雷達(dá)掃描結(jié)果
  point_x = UtilTools.Getrandomarray(15, 300);
  point_y = UtilTools.Getrandomarray(15, 300);

 }

 public void setViewSize(int size) {
  this.viewSize = size;
  setMeasuredDimension(viewSize, viewSize);
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  // TODO Auto-generated method stub
  setMeasuredDimension(viewSize, viewSize);
 }

 public void start() {
  mThread = new ScanThread(this);
  mThread.setName("radar");
  mThread.start();
  threadRunning = true;
  isstart = true;
 }

 public void stop() {
  if (isstart) {
   threadRunning = false;
   isstart = false;
  }
 }

 @Override
 protected void onDraw(Canvas canvas) {
  // TODO Auto-generated method stub
  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintCircle);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 255, mPaintLine);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 125, mPaintLine);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintLine);
  //繪制兩條十字線
  canvas.drawLine(viewSize / 2, 0, viewSize / 2, viewSize, mPaintLine);
  canvas.drawLine(0, viewSize / 2, viewSize, viewSize / 2, mPaintLine);


  //這里在雷達(dá)掃描過(guò)制定圓周度數(shù)后，將隨機(jī)繪制一些白點(diǎn)，模擬搜索結(jié)果
  if (start > 100) {
   for (int i = 0; i < 2; i++) {
    canvas.drawCircle(viewSize / 2 + point_x[i], viewSize / 2 + point_y[i], 10, mPaintPoint);
   }
  }
  if (start > 200) {
   for (int i = 2; i < 5; i++) {
    canvas.drawCircle(viewSize / 2 + point_x[i], viewSize / 2 + point_y[i], 10, mPaintPoint);
   }
  }
  if (start > 300) {
   for (int i = 5; i < 9; i++) {
    canvas.drawCircle(viewSize / 2 + point_x[i], viewSize / 2 + point_y[i], 10, mPaintPoint);
   }
  }
  if (start > 500) {
   for (int i = 9; i < 11; i++) {
    canvas.drawCircle(viewSize / 2 + point_x[i], viewSize / 2 + point_y[i], 10, mPaintPoint);
   }
  }
  if (start > 800) {
   for (int i = 11; i < point_x.length; i++) {
    canvas.drawCircle(viewSize / 2 + point_x[i], viewSize / 2 + point_y[i], 10, mPaintPoint);
   }
  }

  //根據(jù)matrix中設(shè)定角度，不斷繪制shader,呈現(xiàn)出一種扇形掃描效果
  canvas.concat(matrix);
  canvas.drawCircle(viewSize / 2, viewSize / 2, 350, mPaintSector);
  super.onDraw(canvas);
 }

 public void setDirection(@RADAR_DIRECTION int direction) {
  if (direction != CLOCK_WISE && direction != ANTI_CLOCK_WISE) {
   throw new IllegalArgumentException("Use @RADAR_DIRECTION constants only!");
  }
  this.direction = direction;
 }

 protected class ScanThread extends Thread {

  private RadarView view;

  public ScanThread(RadarView view) {
   // TODO Auto-generated constructor stub
   this.view = view;
  }

  @Override
  public void run() {
   // TODO Auto-generated method stub
   while (threadRunning) {
    if (isstart) {
     view.post(new Runnable() {
      public void run() {
       start = start + 1;
       matrix = new Matrix();
       //設(shè)定旋轉(zhuǎn)角度,制定進(jìn)行轉(zhuǎn)轉(zhuǎn)操作的圓心
//       matrix.postRotate(start, viewSize / 2, viewSize / 2);
//       matrix.setRotate(start,viewSize/2,viewSize/2);
       matrix.preRotate(direction*start,viewSize/2,viewSize/2);
       view.invalidate();

      }
     });
     try {
      Thread.sleep(5);
     } catch (InterruptedException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
     }
    }
   }
  }
 }
}

說(shuō)明

多余的部分就不再解釋?zhuān)a里已經(jīng)注釋的很清楚。這個(gè)RadarView的使用也是很簡(jiǎn)單，需要停止時(shí)，調(diào)用其stop方法即可。

@Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  RadarView radarView = (RadarView) findViewById(R.id.radar);
  //設(shè)置雷達(dá)掃描方向
  radarView.setDirection(RadarView.ANTI_CLOCK_WISE);
  radarView.start();
 }

這里雷達(dá)ViewSize設(shè)置為800，所以在布局文件中設(shè)定大小時(shí)將不起作用，正常使用時(shí)，需根據(jù)實(shí)際需求調(diào)整viewsize大小和幾個(gè)Circle的半徑，從而達(dá)到更有好的UI展示效果。

總結(jié)

以上就是Android中雷達(dá)掃描效果實(shí)現(xiàn)的全部?jī)?nèi)容，希望本文對(duì)大家Android開(kāi)發(fā)有所幫助。

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