Androidは任意のViewシャドウ効果を設定

package com.sxu.shadowdrawable;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.view.ViewCompat;
import android.view.View;

public class ShadowDrawable extends Drawable {

   private Paint mShadowPaint;
   private Paint mBgPaint;
   private int mShadowRadius;
   private int mShape;
   private int mShapeRadius;
   private int mOffsetX;
   private int mOffsetY;
   private int mBgColor[];
   private RectF mRect;

   public final static int SHAPE_ROUND = 1;
   public final static int SHAPE_CIRCLE = 2;

   private ShadowDrawable(int shape, int[] bgColor, int shapeRadius, int shadowColor, int shadowRadius, int offsetX, int offsetY) {
      this.mShape = shape;
      this.mBgColor = bgColor;
      this.mShapeRadius = shapeRadius;
      this.mShadowRadius = shadowRadius;
      this.mOffsetX = offsetX;
      this.mOffsetY = offsetY;

      mShadowPaint = new Paint();
      mShadowPaint.setColor(Color.TRANSPARENT);
      mShadowPaint.setAntiAlias(true);
      mShadowPaint.setShadowLayer(shadowRadius, offsetX, offsetY, shadowColor);
      mShadowPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP));

      mBgPaint = new Paint();
      mBgPaint.setAntiAlias(true);
   }

   @Override
   public void setBounds(int left, int top, int right, int bottom) {
      super.setBounds(left, top, right, bottom);
      mRect = new RectF(left + mShadowRadius - mOffsetX, top + mShadowRadius - mOffsetY, right - mShadowRadius - mOffsetX,
            bottom - mShadowRadius - mOffsetY);
   }

   @Override
   public void draw(@NonNull Canvas canvas) {
      if (mBgColor != null) {
         if (mBgColor.length == 1) {
            mBgPaint.setColor(mBgColor[0]);
         } else {
            mBgPaint.setShader(new LinearGradient(mRect.left, mRect.height() / 2, mRect.right,
                  mRect.height() / 2, mBgColor, null, Shader.TileMode.CLAMP));
         }
      }

      if (mShape == SHAPE_ROUND) {
         canvas.drawRoundRect(mRect, mShapeRadius, mShapeRadius, mShadowPaint);
         canvas.drawRoundRect(mRect, mShapeRadius, mShapeRadius, mBgPaint);
      } else {
         canvas.drawCircle(mRect.centerX(), mRect.centerY(), Math.min(mRect.width(), mRect.height())/ 2, mShadowPaint);
         canvas.drawCircle(mRect.centerX(), mRect.centerY(), Math.min(mRect.width(), mRect.height())/ 2, mBgPaint);
      }
   }

   @Override
   public void setAlpha(int alpha) {
      mShadowPaint.setAlpha(alpha);
   }

   @Override
   public void setColorFilter(@Nullable ColorFilter colorFilter) {
      mShadowPaint.setColorFilter(colorFilter);
   }

   @Override
   public int getOpacity() {
      return PixelFormat.TRANSLUCENT;
   }

   public static void setShadowDrawable(View view, Drawable drawable) {
      view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
      ViewCompat.setBackground(view, drawable);
   }

   public static void setShadowDrawable(View view, int shapeRadius, int shadowColor, int shadowRadius, int offsetX, int offsetY) {
      ShadowDrawable drawable = new ShadowDrawable.Builder()
            .setShapeRadius(shapeRadius)
            .setShadowColor(shadowColor)
            .setShadowRadius(shadowRadius)
            .setOffsetX(offsetX)
            .setOffsetY(offsetY)
            .builder();
      view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
      ViewCompat.setBackground(view, drawable);
   }

   public static void setShadowDrawable(View view, int bgColor, int shapeRadius, int shadowColor, int shadowRadius, int offsetX, int offsetY) {
      ShadowDrawable drawable = new ShadowDrawable.Builder()
            .setBgColor(bgColor)
            .setShapeRadius(shapeRadius)
            .setShadowColor(shadowColor)
            .setShadowRadius(shadowRadius)
            .setOffsetX(offsetX)
            .setOffsetY(offsetY)
            .builder();
      view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
      ViewCompat.setBackground(view, drawable);
   }

   public static void setShadowDrawable(View view, int shape, int bgColor, int shapeRadius, int shadowColor, int shadowRadius, int offsetX, int offsetY) {
      ShadowDrawable drawable = new ShadowDrawable.Builder()
            .setShape(shape)
            .setBgColor(bgColor)
            .setShapeRadius(shapeRadius)
            .setShadowColor(shadowColor)
            .setShadowRadius(shadowRadius)
            .setOffsetX(offsetX)
            .setOffsetY(offsetY)
            .builder();
      view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
      ViewCompat.setBackground(view, drawable);
   }

   public static void setShadowDrawable(View view, int[] bgColor, int shapeRadius, int shadowColor, int shadowRadius, int offsetX, int offsetY) {
      ShadowDrawable drawable = new ShadowDrawable.Builder()
            .setBgColor(bgColor)
            .setShapeRadius(shapeRadius)
            .setShadowColor(shadowColor)
            .setShadowRadius(shadowRadius)
            .setOffsetX(offsetX)
            .setOffsetY(offsetY)
            .builder();
      view.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
      ViewCompat.setBackground(view, drawable);
   }

   public static class Builder {
      private int mShape;
      private int mShapeRadius;
      private int mShadowColor;
      private int mShadowRadius;
      private int mOffsetX = 0;
      private int mOffsetY = 0;
      private int[] mBgColor;

      public Builder() {
         mShape = ShadowDrawable.SHAPE_ROUND;
         mShapeRadius = 12;
         mShadowColor = Color.parseColor("#4d000000");
         mShadowRadius = 18;
         mOffsetX = 0;
         mOffsetY = 0;
         mBgColor = new int[1];
         mBgColor[0] = Color.TRANSPARENT;
      }

      public Builder setShape(int mShape) {
         this.mShape = mShape;
         return this;
      }

      public Builder setShapeRadius(int ShapeRadius) {
         this.mShapeRadius = ShapeRadius;
         return this;
      }

      public Builder setShadowColor(int shadowColor) {
         this.mShadowColor = shadowColor;
         return this;
      }

      public Builder setShadowRadius(int shadowRadius) {
         this.mShadowRadius = shadowRadius;
         return this;
      }

      public Builder setOffsetX(int OffsetX) {
         this.mOffsetX = OffsetX;
         return this;
      }

      public Builder setOffsetY(int OffsetY) {
         this.mOffsetY = OffsetY;
         return this;
      }

      public Builder setBgColor(int BgColor) {
         this.mBgColor[0] = BgColor;
         return this;
      }

      public Builder setBgColor(int[] BgColor) {
         this.mBgColor = BgColor;
         return this;
      }

      public ShadowDrawable builder() {
         return new ShadowDrawable(mShape, mBgColor, mShapeRadius, mShadowColor, mShadowRadius, mOffsetX, mOffsetY);
      }
   }
}

 
 
使用法

mMeditaVoiceSettingLayout.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {

        if (hasFocus) {
            mMeditaVoiceSettingLayout.setBackground(getResources().getDrawable(R.drawable.linlayout_setting_radio_yello_bg));
            mSettingAudioTv.setTextColor(getResources().getColor(R.color.focus_text_color));
            mSettingAudioImg.setImageResource(R.drawable.ic_setting_audio_white);
            ShadowDrawable.setShadowDrawable(mMeditaVoiceSettingLayout, Color.parseColor("#a69006"), FunctionUtil.dpToPx(shadowRadius_a),
                    Color.parseColor("#cca69006"), FunctionUtil.dpToPx(shadowRadius_b), 0, 0);
        } else {
            mMeditaVoiceSettingLayout.setBackground(getResources().getDrawable(R.drawable.linlayout_setting_radio_bg));
            mSettingAudioTv.setTextColor(getResources().getColor(R.color.new_text_color));
            mSettingAudioImg.setImageResource(R.drawable.ic_setting_audio);
            ShadowDrawable.setShadowDrawable(mMeditaVoiceSettingLayout, Color.parseColor("#363e55"), FunctionUtil.dpToPx(shadowRadius_a),
                    Color.parseColor("#ff363e55"), FunctionUtil.dpToPx(shadowRadius_b), 0, 0);
        }
    }
});