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. * 女神面部掃描 */public class ShaderView3 extends View {  /**   * 繪制掃描圈的筆   */  private Paint mSweepPaint;  /**   * 繪制女神bitmap的筆   */  private Paint mBitmapPaint;  /**   * 這個自定義View的寬度，就是你在xml布局里面設置的寬度（目前不支持）   */  private int mWidth;  /**   * 女神圖片   */  private Bitmap mBitmap;  /**   * 雷達掃描旋轉角度   */  private int degrees = 0;  /**   * 用于控制掃描圈的矩陣   */  Matrix mSweepMatrix = new Matrix();  /**   * 用于控制女神Bitmap的矩陣   */  Matrix mBitmapMatrix = new Matrix();  /**   * 著色器---生成掃描圈   */  private SweepGradient mSweepGradient;  /**   * 圖片著色器   */  private BitmapShader mBitmapShader;  private float mScale;  public ShaderView3(Context context) {    super(context);    init();  }  public ShaderView3(Context context, @Nullable AttributeSet attrs) {    super(context, attrs);    init();  }  /**   * 屬性動畫，必須有setXxx方法，才可以針對這個屬性實現(xiàn)動畫   *   * @param degrees   */  public void setDegrees(int degrees) {    this.degrees = degrees;    postInvalidate();//在主線程里執(zhí)行OnDraw  }  private void init() {//    1.準備好畫筆    mSweepPaint = new Paint();    mBitmapPaint = new Paint();//    2.圖片著色器    mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ccc);    mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);//    3.將圖片著色器設置給畫筆    mBitmapPaint.setShader(mBitmapShader);  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);//    獲取這個自定義view的寬高，注意在onMeasure里獲取，在構造函數(shù)里得到的是0    mWidth = getMeasuredWidth();//    根據(jù)你所設置的view的尺寸和bitmap的尺寸計算一個縮放比例，否則的話，得到的圖片是一個局部，而不是一整張圖片    mScale = (float) mWidth / (float) mBitmap.getWidth();//    4.梯度掃描著色器    mSweepGradient = new SweepGradient(mWidth / 2, mWidth / 2, new int[]{Color.argb(200, 200, 0, 0), Color.argb(10, 30, 0, 0)}, null);//    5.將梯度掃描著色器設置給另外一支畫筆    mSweepPaint.setShader(mSweepGradient);  }  @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);//    迫不得已的時候，才在onDraw方法寫代碼，能提前準備的要在之前去準備，//    不要寫在onDraw里面，因為onDraw會不停地刷新繪制，寫的代碼越多，越影響效率//    將圖片縮放至你指定的自定義View的寬高    mBitmapMatrix.setScale(mScale, mScale);    mBitmapShader.setLocalMatrix(mBitmapMatrix);//   設置掃描圈旋轉角度    mSweepMatrix.setRotate(degrees, mWidth / 2, mWidth / 2);    mSweepGradient.setLocalMatrix(mSweepMatrix);//    5. 使用設置好圖片著色器的畫筆，畫圓，先畫出下層的女神圖片，在畫出上層的掃描圖片    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>