代码如下所示
/**
* <pre>
* @author yangchong
* blog : https://github.com/yangchong211
* time : 2018/7/20
* desc : 自定义阴影
* revise:
* </pre>
*/
public class ShadowLayout extends FrameLayout {
/**
* 阴影颜色
*/
private int mShadowColor;
/**
* 阴影的扩散范围(也可以理解为扩散程度)
*/
private float mShadowLimit;
/**
* 阴影的圆角大小
*/
private float mCornerRadius;
/**
* x轴的偏移量
*/
private float mDx;
/**
* y轴的偏移量
*/
private float mDy;
/**
* 左边是否显示阴影
*/
private boolean leftShow;
/**
* 右边是否显示阴影
*/
private boolean rightShow;
/**
* 上边是否显示阴影
*/
private boolean topShow;
/**
* 下面是否显示阴影
*/
private boolean bottomShow;
private boolean mInvalidateShadowOnSizeChanged = true;
private boolean mForceInvalidateShadow = false;
public ShadowLayout(Context context) {
super(context);
initView(context, null);
}
public ShadowLayout(Context context, AttributeSet attrs) {
super(context, attrs);
initView(context, attrs);
}
public ShadowLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initView(context, attrs);
}
@Override
protected int getSuggestedMinimumWidth() {
return 0;
}
@Override
protected int getSuggestedMinimumHeight() {
return 0;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (w > 0 && h > 0 && (getBackground() == null || mInvalidateShadowOnSizeChanged
|| mForceInvalidateShadow)) {
mForceInvalidateShadow = false;
setBackgroundCompat(w, h);
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
if (mForceInvalidateShadow) {
mForceInvalidateShadow = false;
setBackgroundCompat(right - left, bottom - top);
}
}
public void setInvalidateShadowOnSizeChanged(boolean invalidateShadowOnSizeChanged) {
mInvalidateShadowOnSizeChanged = invalidateShadowOnSizeChanged;
}
public void invalidateShadow() {
mForceInvalidateShadow = true;
requestLayout();
invalidate();
}
private void initView(Context context, AttributeSet attrs) {
initAttributes(context, attrs);
int xPadding = (int) (mShadowLimit + Math.abs(mDx));
int yPadding = (int) (mShadowLimit + Math.abs(mDy));
int left;
int right;
int top;
int bottom;
if (leftShow) {
left = xPadding;
} else {
left = 0;
}
if (topShow) {
top = yPadding;
} else {
top = 0;
}
if (rightShow) {
right = xPadding;
} else {
right = 0;
}
if (bottomShow) {
bottom = yPadding;
} else {
bottom = 0;
}
setPadding(left, top, right, bottom);
}
@SuppressWarnings("deprecation")
private void setBackgroundCompat(int w, int h) {
Bitmap bitmap = createShadowBitmap(w, h, mCornerRadius, mShadowLimit, mDx,
mDy, mShadowColor, Color.TRANSPARENT);
BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap);
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.JELLY_BEAN) {
setBackgroundDrawable(drawable);
} else {
setBackground(drawable);
}
}
private void initAttributes(Context context, AttributeSet attrs) {
TypedArray attr = getTypedArray(context, attrs, R.styleable.ShadowLayout);
if (attr == null) {
return;
}
try {
//默认是显示
leftShow = attr.getBoolean(R.styleable.ShadowLayout_yc_leftShow, true);
rightShow = attr.getBoolean(R.styleable.ShadowLayout_yc_rightShow, true);
bottomShow = attr.getBoolean(R.styleable.ShadowLayout_yc_bottomShow, true);
topShow = attr.getBoolean(R.styleable.ShadowLayout_yc_topShow, true);
mCornerRadius = attr.getDimension(R.styleable.ShadowLayout_yc_cornerRadius, 0);
mShadowLimit = attr.getDimension(R.styleable.ShadowLayout_yc_shadowLimit, 0);
mDx = attr.getDimension(R.styleable.ShadowLayout_yc_dx, 0);
mDy = attr.getDimension(R.styleable.ShadowLayout_yc_dy, 0);
mShadowColor = attr.getColor(R.styleable.ShadowLayout_yc_shadowColor,
getResources().getColor(R.color.default_shadow_color));
} finally {
attr.recycle();
}
}
private TypedArray getTypedArray(Context context, AttributeSet attributeSet, int[] attr) {
return context.obtainStyledAttributes(attributeSet, attr, 0, 0);
}
private Bitmap createShadowBitmap(int shadowWidth, int shadowHeight, float cornerRadius,
float shadowRadius, float dx, float dy,
int shadowColor, int fillColor) {
//根据宽高创建bitmap背景
Bitmap output = Bitmap.createBitmap(shadowWidth, shadowHeight, Bitmap.Config.ARGB_8888);
//用画板canvas进行绘制
Canvas canvas = new Canvas(output);
RectF shadowRect = new RectF(shadowRadius, shadowRadius,
shadowWidth - shadowRadius, shadowHeight - shadowRadius);
if (dy > 0) {
shadowRect.top += dy;
shadowRect.bottom -= dy;
} else if (dy < 0) {
shadowRect.top += Math.abs(dy);
shadowRect.bottom -= Math.abs(dy);
}
if (dx > 0) {
shadowRect.left += dx;
shadowRect.right -= dx;
} else if (dx < 0) {
shadowRect.left += Math.abs(dx);
shadowRect.right -= Math.abs(dx);
}
Paint shadowPaint = new Paint();
shadowPaint.setAntiAlias(true);
shadowPaint.setColor(fillColor);
shadowPaint.setStyle(Paint.Style.FILL);
if (!isInEditMode()) {
shadowPaint.setShadowLayer(shadowRadius, dx, dy, shadowColor);
}
canvas.drawRoundRect(shadowRect, cornerRadius, cornerRadius, shadowPaint);
return output;
}
}
