Android 给控件加上阴影

这篇需求———需要动态设置控件的阴影颜色

网上搜了许多，最后定位到ShadowLayout这个控件，使用起来简单，但是只支持圆形和长方形

如果是圆角就不行了

于是再其的基础上做了修改

下面说使用方法

xml调用

<com.luoy.blackdoplanet.common.untils.ShadowLayout
    android:id="@+id/sh_shap"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    app:shadowDx="0dp"
    app:shadowDy="0dp"
    app:shadowShapeRad="26dp"
    app:shadowRadius="4dp"
    app:shadowShape="shap"
    app:shadowSide="all">

    <TextView
        android:id="@+id/tv_com"
        android:layout_width="@dimen/dp90"
        android:layout_height="@dimen/dp26"
        android:gravity="center"
        android:text="去完成"
        android:textColor="@color/white" />
</com.luoy.blackdoplanet.common.untils.ShadowLayout>

需要包含别的控件使用

在attrs中加入

<!-- ShadowLayout 阴影 -->
<declare-styleable name="ShadowLayout">
    <attr name="shadowColor" format="color"/>
    <attr name="shadowRadius" format="dimension"/>
    <attr name="shadowDx" format="dimension"/>
    <attr name="shadowDy" format="dimension"/>
    <attr name="shadowShapeRad" format="dimension"/>
    <attr name="shadowShape">
        <flag name="rectangle" value="0x0001"/>
        <flag name="oval" value="0x0010"/>
        <flag name="shap" value="0x0011"/>
    </attr>
    <attr name="shadowSide">
        <flag name="all" value="0x1111"/>
        <flag name="left" value="0x0001"/>
        <flag name="top" value="0x0010"/>
        <flag name="right" value="0x0100"/>
        <flag name="bottom" value="0x1000"/>
    </attr>
</declare-styleable>

各个属性都很简单

• app:shadowColor="#66000000" 控制阴影的颜色

• app:shadowDx="0dp" 控制阴影 x 轴的偏移量

• app:shadowDy="3dp" 控制阴影 y 轴的偏移量

• app:shadowRadius="10dp" 控制阴影的范围

• app:shadowSide="all|left|right|top|bottom" 控制阴影显示的边界，共有五个值

• shadowShape 阴影的形状

• shadowShapeRad 圆角的度数

• shadowColor必须加上透明度

• 附上代码

• package com.luoy.blackdoplanet.common.untils;
  
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.graphics.Canvas;
  import android.graphics.Color;
  import android.graphics.Paint;
  import android.graphics.RectF;
  import android.util.AttributeSet;
  import android.util.DisplayMetrics;
  import android.view.View;
  import android.widget.RelativeLayout;
  
  import com.botaoweb.blackdoplanet.R;
  
  /**
   * ShadowLayout.java
   * <p>
   * Created by lijiankun on 17/8/11.
   */
  
  public class ShadowLayout extends RelativeLayout {
  
      public static final int ALL = 0x1111;
  
      public static final int LEFT = 0x0001;
  
      public static final int TOP = 0x0010;
  
      public static final int RIGHT = 0x0100;
  
      public static final int BOTTOM = 0x1000;
  
      public static final int SHAPE_RECTANGLE = 0x0001;
  
      public static final int SHAPE_OVAL = 0x0010;
  
      public static final int SHAPE_SHAP = 0x0011;
  
  
      private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
  
      private RectF mRectF = new RectF();
  
      /**
       * 阴影的颜色
       */
      private int mShadowColor = Color.TRANSPARENT;
  
      /**
       * 阴影的大小范围
       */
      private float mShadowRadius = 0;
  
      /**
       * 阴影 x 轴的偏移量
       */
      private float mShadowDx = 0;
  
      /**
       * 阴影 y 轴的偏移量
       */
      private float mShadowDy = 0;
  
      /**
       * 阴影显示的边界
       */
      private int mShadowSide = ALL;
  
      /**
       * 圆角弧度
       */
      private float mShadowShapRad = 0;
  
      /**
       * 阴影的形状，圆形/矩形
       */
      private int mShadowShape = SHAPE_RECTANGLE;
  
      public ShadowLayout(Context context) {
          this(context, null);
      }
  
      public ShadowLayout(Context context, AttributeSet attrs) {
          this(context, attrs, 0);
      }
  
      public ShadowLayout(Context context, AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
          init(attrs);
      }
  
      @Override
      protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
          super.onMeasure(widthMeasureSpec, heightMeasureSpec);
          float effect = mShadowRadius + dip2px(5);
          float rectLeft = 0;
          float rectTop = 0;
          float rectRight = this.getMeasuredWidth();
          float rectBottom = this.getMeasuredHeight();
          int paddingLeft = 0;
          int paddingTop = 0;
          int paddingRight = 0;
          int paddingBottom = 0;
          this.getWidth();
          if ((mShadowSide & LEFT) == LEFT) {
              rectLeft = effect;
              paddingLeft = (int) effect;
          }
          if ((mShadowSide & TOP) == TOP) {
              rectTop = effect;
              paddingTop = (int) effect;
          }
          if ((mShadowSide & RIGHT) == RIGHT) {
              rectRight = this.getMeasuredWidth() - effect;
              paddingRight = (int) effect;
          }
          if ((mShadowSide & BOTTOM) == BOTTOM) {
              rectBottom = this.getMeasuredHeight() - effect;
              paddingBottom = (int) effect;
          }
          if (mShadowDy != 0.0f) {
              rectBottom = rectBottom - mShadowDy;
              paddingBottom = paddingBottom + (int) mShadowDy;
          }
          if (mShadowDx != 0.0f) {
              rectRight = rectRight - mShadowDx;
              paddingRight = paddingRight + (int) mShadowDx;
          }
          mRectF.left = rectLeft;
          mRectF.top = rectTop;
          mRectF.right = rectRight;
          mRectF.bottom = rectBottom;
          this.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
      }
  
      /**
       * 真正绘制阴影的方法
       */
      @Override
      protected void onDraw(Canvas canvas) {
          super.onDraw(canvas);
          setUpShadowPaint();
          if (mShadowShape == SHAPE_RECTANGLE) {
              canvas.drawRect(mRectF, mPaint);
          } else if (mShadowShape == SHAPE_OVAL) {
              canvas.drawCircle(mRectF.centerX(), mRectF.centerY(), Math.min(mRectF.width(), mRectF.height()) / 2, mPaint);
          }else if(mShadowShape == SHAPE_SHAP){
              canvas.drawRoundRect(mRectF, mShadowShapRad, mShadowShapRad,mPaint);//第二个参数是x半径，第三个参数是y半径
          }
      }
  
      public void setShadowColor(int shadowColor) {
          mShadowColor = shadowColor;
          requestLayout();
          postInvalidate();
      }
  
      public void setShadowRadius(float shadowRadius) {
          mShadowRadius = shadowRadius;
          requestLayout();
          postInvalidate();
      }
  
      /**
       * 读取设置的阴影的属性
       *
       * @param attrs 从其中获取设置的值
       */
      private void init(AttributeSet attrs) {
          setLayerType(View.LAYER_TYPE_SOFTWARE, null);  // 关闭硬件加速
          this.setWillNotDraw(false);                    // 调用此方法后，才会执行 onDraw(Canvas) 方法
  
          TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.ShadowLayout);
          if (typedArray != null) {
              mShadowColor = typedArray.getColor(R.styleable.ShadowLayout_shadowColor,
                      getContext().getResources().getColor(android.R.color.black));
              mShadowRadius = typedArray.getDimension(R.styleable.ShadowLayout_shadowRadius, dip2px(0));
              mShadowDx = typedArray.getDimension(R.styleable.ShadowLayout_shadowDx, dip2px(0));
              mShadowDy = typedArray.getDimension(R.styleable.ShadowLayout_shadowDy, dip2px(0));
              mShadowSide = typedArray.getInt(R.styleable.ShadowLayout_shadowSide, ALL);
              mShadowShape = typedArray.getInt(R.styleable.ShadowLayout_shadowShape, SHAPE_RECTANGLE);
              mShadowShapRad= typedArray.getDimension(R.styleable.ShadowLayout_shadowShapeRad,dip2px(0));
              typedArray.recycle();
          }
          setUpShadowPaint();
      }
  
      private void setUpShadowPaint() {
          mPaint.reset();
          mPaint.setAntiAlias(true);
          mPaint.setColor(Color.TRANSPARENT);
          mPaint.setShadowLayer(mShadowRadius, mShadowDx, mShadowDy, mShadowColor);
      }
  
      /**
       * dip2px dp 值转 px 值
       *
       * @param dpValue dp 值
       * @return px 值
       */
      private float dip2px(float dpValue) {
          DisplayMetrics dm = getContext().getResources().getDisplayMetrics();
          float scale = dm.density;
          return (dpValue * scale + 0.5F);
      }
  }
  

• demo下载https://download.csdn.net/download/qq_30711091/10596342