Bạn có thể sử dụng lớp sau cho thẻ xml:
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.os.Build;
import android.support.annotation.FloatRange;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.widget.FrameLayout;
import com.webappmate.weeassure.R;
public class ShadowLayout extends FrameLayout {
private final static float DEFAULT_SHADOW_RADIUS = 30.0F;
private final static float DEFAULT_SHADOW_DISTANCE = 15.0F;
private final static float DEFAULT_SHADOW_ANGLE = 45.0F;
private final static int DEFAULT_SHADOW_COLOR = Color.DKGRAY;
private final static int MAX_ALPHA = 255;
private final static float MAX_ANGLE = 360.0F;
private final static float MIN_RADIUS = 0.1F;
private final static float MIN_ANGLE = 0.0F;
private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG) {
{
setDither(true);
setFilterBitmap(true);
}
};
private Bitmap mBitmap;
private final Canvas mCanvas = new Canvas();
private final Rect mBounds = new Rect();
private boolean mInvalidateShadow = true;
private boolean mIsShadowed;
private int mShadowColor;
private int mShadowAlpha;
private float mShadowRadius;
private float mShadowDistance;
private float mShadowAngle;
private float mShadowDx;
private float mShadowDy;
public ShadowLayout(final Context context) {
this(context, null);
}
public ShadowLayout(final Context context, final AttributeSet attrs) {
this(context, attrs, 0);
}
public ShadowLayout(final Context context, final AttributeSet attrs, final int defStyleAttr) {
super(context, attrs, defStyleAttr);
setWillNotDraw(false);
setLayerType(LAYER_TYPE_HARDWARE, mPaint);
final TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ShadowLayout);
try {
setIsShadowed(typedArray.getBoolean(R.styleable.ShadowLayout_sl_shadowed, true));
setShadowRadius(
typedArray.getDimension(
R.styleable.ShadowLayout_sl_shadow_radius, DEFAULT_SHADOW_RADIUS
)
);
setShadowDistance(
typedArray.getDimension(
R.styleable.ShadowLayout_sl_shadow_distance, DEFAULT_SHADOW_DISTANCE
)
);
setShadowAngle(
typedArray.getInteger(
R.styleable.ShadowLayout_sl_shadow_angle, (int) DEFAULT_SHADOW_ANGLE
)
);
setShadowColor(
typedArray.getColor(
R.styleable.ShadowLayout_sl_shadow_color, DEFAULT_SHADOW_COLOR
)
);
} finally {
typedArray.recycle();
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
if (mBitmap != null) {
mBitmap.recycle();
mBitmap = null;
}
}
public boolean isShadowed() {
return mIsShadowed;
}
public void setIsShadowed(final boolean isShadowed) {
mIsShadowed = isShadowed;
postInvalidate();
}
public float getShadowDistance() {
return mShadowDistance;
}
public void setShadowDistance(final float shadowDistance) {
mShadowDistance = shadowDistance;
resetShadow();
}
public float getShadowAngle() {
return mShadowAngle;
}
@SuppressLint("SupportAnnotationUsage")
@FloatRange
public void setShadowAngle(@FloatRange(from = MIN_ANGLE, to = MAX_ANGLE) final float shadowAngle) {
mShadowAngle = Math.max(MIN_ANGLE, Math.min(shadowAngle, MAX_ANGLE));
resetShadow();
}
public float getShadowRadius() {
return mShadowRadius;
}
public void setShadowRadius(final float shadowRadius) {
mShadowRadius = Math.max(MIN_RADIUS, shadowRadius);
if (isInEditMode()) return;
mPaint.setMaskFilter(new BlurMaskFilter(mShadowRadius, BlurMaskFilter.Blur.NORMAL));
resetShadow();
}
public int getShadowColor() {
return mShadowColor;
}
public void setShadowColor(final int shadowColor) {
mShadowColor = shadowColor;
mShadowAlpha = Color.alpha(shadowColor);
resetShadow();
}
public float getShadowDx() {
return mShadowDx;
}
public float getShadowDy() {
return mShadowDy;
}
private void resetShadow() {
mShadowDx = (float) ((mShadowDistance) * Math.cos(mShadowAngle / 180.0F * Math.PI));
mShadowDy = (float) ((mShadowDistance) * Math.sin(mShadowAngle / 180.0F * Math.PI));
final int padding = (int) (mShadowDistance + mShadowRadius);
setPadding(padding, padding, padding, padding);
requestLayout();
}
private int adjustShadowAlpha(final boolean adjust) {
return Color.argb(
adjust ? MAX_ALPHA : mShadowAlpha,
Color.red(mShadowColor),
Color.green(mShadowColor),
Color.blue(mShadowColor)
);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mBounds.set(
0, 0, MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(heightMeasureSpec)
);
}
@Override
public void requestLayout() {
mInvalidateShadow = true;
super.requestLayout();
}
@Override
protected void dispatchDraw(final Canvas canvas) {
if (mIsShadowed) {
if (mInvalidateShadow) {
if (mBounds.width() != 0 && mBounds.height() != 0) {
mBitmap = Bitmap.createBitmap(
mBounds.width(), mBounds.height(), Bitmap.Config.ARGB_8888
);
mCanvas.setBitmap(mBitmap);
mInvalidateShadow = false;
super.dispatchDraw(mCanvas);
final Bitmap extractedAlpha = mBitmap.extractAlpha();
mCanvas.drawColor(0, PorterDuff.Mode.CLEAR);
mPaint.setColor(adjustShadowAlpha(false));
mCanvas.drawBitmap(extractedAlpha, mShadowDx, mShadowDy, mPaint);
extractedAlpha.recycle();
} else {
mBitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.RGB_565);
}
}
mPaint.setColor(adjustShadowAlpha(true));
if (mCanvas != null && mBitmap != null && !mBitmap.isRecycled())
canvas.drawBitmap(mBitmap, 0.0F, 0.0F, mPaint);
}
super.dispatchDraw(canvas);
}
}
sử dụng Tag trong xml như thế này:
<yourpackagename.ShadowLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
app:sl_shadow_color="#9e000000"
app:sl_shadow_radius="4dp">
<child views>
</yourpackagename.ShadowLayout>
CẬP NHẬT
đặt mã dưới đây trong attrs.xml trong tài nguyên >> giá trị
<declare-styleable name="ShadowLayout">
<attr name="sl_shadowed" format="boolean"/>
<attr name="sl_shadow_distance" format="dimension"/>
<attr name="sl_shadow_angle" format="integer"/>
<attr name="sl_shadow_radius" format="dimension"/>
<attr name="sl_shadow_color" format="color"/>
</declare-styleable>
