Android Shader 응용 개발 레이더 스캐닝 효과

package com.example.apple.shaderdemo;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.graphics.SweepGradient;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;

/**
 * Created by apple on 2017/5/23.
 *       
 */

public class ShaderView3 extends View {

  /**
   *        
   */
  private Paint mSweepPaint;
  /**
   *     bitmap  
   */
  private Paint mBitmapPaint;
  /**
   *      View   ，    xml         （     ）
   */
  private int mWidth;
  /**
   *     
   */
  private Bitmap mBitmap;
  /**
   *         
   */
  private int degrees = 0;
  /**
   *           
   */
  Matrix mSweepMatrix = new Matrix();
  /**
   *       Bitmap   
   */
  Matrix mBitmapMatrix = new Matrix();
  /**
   *    ---     
   */
  private SweepGradient mSweepGradient;
  /**
   *      
   */
  private BitmapShader mBitmapShader;
  private float mScale;

  public ShaderView3(Context context) {
    super(context);
    init();
  }

  public ShaderView3(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  /**
   *     ，   setXxx  ，             
   *
   * @param degrees
   */
  public void setDegrees(int degrees) {
    this.degrees = degrees;
    postInvalidate();//       OnDraw
  }

  private void init() {
//    1.     
    mSweepPaint = new Paint();
    mBitmapPaint = new Paint();
//    2.     
    mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ccc);
    mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
//    3.           
    mBitmapPaint.setShader(mBitmapShader);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//           view   ，   onMeasure   ，          0
    mWidth = getMeasuredWidth();
//           view    bitmap           ，    ，          ，        
    mScale = (float) mWidth / (float) mBitmap.getWidth();
//    4.       
    mSweepGradient = new SweepGradient(mWidth / 2, mWidth / 2, new int[]{Color.argb(200, 200, 0, 0), Color.argb(10, 30, 0, 0)}, null);
//    5.                 
    mSweepPaint.setShader(mSweepGradient);


  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
//           ，  onDraw     ，             ，
//        onDraw  ，  onDraw        ，      ，     


//                 View   
    mBitmapMatrix.setScale(mScale, mScale);
    mBitmapShader.setLocalMatrix(mBitmapMatrix);

//            
    mSweepMatrix.setRotate(degrees, mWidth / 2, mWidth / 2);
    mSweepGradient.setLocalMatrix(mSweepMatrix);

//    5.              ，  ，          ，          
    canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mBitmapPaint);
    canvas.drawCircle(mWidth / 2, mWidth / 2, mWidth / 2, mSweepPaint);


  }
}

package com.example.apple.shaderdemo;

import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.animation.LinearInterpolator;

public class MainActivity extends AppCompatActivity {

  private ShaderView3 mShaderView;
  int degrees = 0;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mShaderView = (ShaderView3) findViewById(R.id.sv);

    mShaderView.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        ObjectAnimator degrees = ObjectAnimator.ofInt(mShaderView, "degrees", 0, 360);
        degrees.setInterpolator(new LinearInterpolator());
        degrees.setDuration(10000);
        degrees.setRepeatCount(ValueAnimator.INFINITE);
        degrees.start();
        /* new Thread(new Runnable() {
          @Override
          public void run() {
            while (degrees <= 360) {
              degrees += 1;
              mShaderView.setDegrees(degrees);

              try {
                Thread.sleep(30);
              } catch (InterruptedException e) {
                e.printStackTrace();
              }
            }


          }
        }).start();

        degrees = 0;
        mShaderView.setDegrees(degrees);*/


      }
    });
  }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context="com.example.apple.shaderdemo.MainActivity">

  <com.example.apple.shaderdemo.ShaderView3
    android:id="@+id/sv"
    android:layout_width="300dp"
    android:layout_height="300dp"
    />

</LinearLayout>