ImageView陰影和圖層效果

import android.app.Activity;<br />import android.content.Context;<br />import android.graphics.Bitmap;<br />import android.graphics.BitmapFactory;<br />import android.graphics.Canvas;<br />import android.graphics.Color;<br />import android.graphics.Paint;<br />import android.graphics.PorterDuff;<br />import android.graphics.PorterDuff.Mode;<br />import android.graphics.PorterDuffXfermode;<br />import android.graphics.Rect;<br />import android.graphics.RectF;<br />import android.graphics.drawable.Drawable;<br />import android.os.Bundle;<br />import android.view.View;</p><p>public class MyCanvasActivity extends Activity {<br /> /** Called when the activity is first created. */<br /> @Override<br /> public void onCreate(Bundle savedInstanceState) {<br /> super.onCreate(savedInstanceState);<br /> setContentView(new ImageEffect(this));<br /> }</p><p> class ImageEffect extends View{<br /> Paint paint;<br /> public ImageEffect(Context context){<br /> super(context);<br /> paint= new Paint(); //初始化畫筆，為後面陰影製作效果使用。<br /> paint.setAntiAlias(true);//去除鋸齒。<br /> paint.setShadowLayer(5f, 5.0f, 5.0f, Color.BLACK); //設定陰影層，這是關鍵。<br /> paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));</p><p> }<br /> public void onDraw(Canvas canvas){<br /> super.onDraw(canvas);<br /> int posX = 20;<br /> int posY = 50;<br /> int PicWidth,PicHeight;</p><p> Drawable drawable = getResources().getDrawable(R.drawable.pic);<br /> Drawable dbe = getResources().getDrawable(R.drawable.pic).mutate();//如果不調用mutate方法，則原圖也會被改變，因為調用的資源是同一個，所有對象是共用狀態的。<br /> Drawable drawTest = getResources().getDrawable(R.drawable.pic);<br /> Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pic);<br /> PicWidth = drawable.getIntrinsicWidth();<br /> PicHeight = drawable.getIntrinsicHeight();</p><p> drawTest.setBounds(posX, (2 * posY) + PicHeight, posX + PicWidth, (2 * posY) + 2 * PicHeight );<br /> drawable.setBounds(posX,posY,posX+PicWidth,posY+PicHeight);<br /> dbe.setBounds(0, 0, PicWidth, PicHeight);</p><p> canvas.drawColor(Color.WHITE);//設定畫布顏色<br /> canvas.save(Canvas.MATRIX_SAVE_FLAG);<br /> dbe.setColorFilter(0x7f000000,PorterDuff.Mode.SRC_IN);<br /> canvas.translate(posX + (int)(0.9 * PicWidth/2), posY + PicHeight/2);//映像平移為了剛好在原圖後形成影子效果。<br /> canvas.skew(-0.9F, 0.0F);//映像傾斜效果。<br /> canvas.scale(1.0f, 0.5f);//映像（其實是畫布）縮放，Y方向縮小為1/2。<br /> dbe.draw(canvas);//此處為畫原映像影子，比原圖先畫，則會在下層。<br /> drawable.clearColorFilter();<br /> canvas.restore();</p><p> canvas.save(Canvas.MATRIX_SAVE_FLAG);<br /> drawable.draw(canvas);//此處為畫原映像，由於canvas有層次效果，因此會蓋在影子之上。<br /> canvas.restore();</p><p> //預設無效果原圖<br /> canvas.save(Canvas.MATRIX_SAVE_FLAG);<br /> drawTest.draw(canvas);<br /> canvas.restore();</p><p> //圖片陰影製作效果<br /> Rect rect = new Rect(2*posX + PicWidth + 3, 2*posY + PicHeight + 3, 2*posX + 2*PicWidth - 2, 2*posY + 2*PicHeight - 2);<br /> //由於圖片的實際尺寸比顯示出來的映像要大一些，因此需要適當更改下大小，以達到較好的效果</p><p> RectF rectF = new RectF(rect);<br /> canvas.drawRoundRect(rectF, 10f, 10f, paint);//在原有矩形基礎上，畫成圓角矩形，同時帶有陰影層。<br /> canvas.drawBitmap(bmp, 2*posX + PicWidth, 2*posY + PicHeight, null);//畫上原圖。<br /> canvas.restore();<br /> }<br /> }<br />}