ImageView倒影效果

ImageView倒影效果的两种方法

第一种：
写个图片的工具类，在Activity中用java代码调用ImageView组件的setImageBitmap(Bitmap bitmap)方法。
下面是图片工具类：

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.Drawable;

public class ImageUtils {

	/** 
	  * 从SDCard上读取图片 
	  * @param pathName 
	  * @return */
	public static Bitmap getBitmapFromSDCard(String pathName) {
		return BitmapFactory.decodeFile(pathName);
	}

	/** 
	  * 缩放图片 
	  * @param bitmap 
	  * @param width 
	  * @param height 
	  * @return */
	public static Bitmap zoomBitmap(Bitmap bitmap, int width, int height) {
		int w = bitmap.getWidth();
		int h = bitmap.getHeight();
		Matrix matrix = new Matrix();
		matrix.postScale((float) width / w, (float) height / h);
		return Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
	}

	/** 
	  * 将Drawable转化为Bitmap 
	  * @param drawable 
	  * @return 
	  */
	public static Bitmap drawableToBitmap(Drawable drawable) {
		int width = drawable.getIntrinsicWidth();
		int height = drawable.getIntrinsicHeight();
		Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
				.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
				: Bitmap.Config.RGB_565);
		Canvas canvas = new Canvas(bitmap);
		drawable.setBounds(0, 0, width, height);
		drawable.draw(canvas);
		return bitmap;
	}

	/** 
	  * 获得圆角图片 
	  * @param bitmap 
	  * @param roundPx 
	  * @return 
	  */
	public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
		Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
				.getHeight(), Config.ARGB_8888);
		Canvas canvas = new Canvas(output);
		final Paint paint = new Paint();
		final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
		final RectF rectF = new RectF(rect);
		canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
		paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
		canvas.drawBitmap(bitmap, rect, rect, paint);
		return output;
	}

	/** 
	  * 获得带倒影的图片 
	  * @param bitmap 
	  * @return 
	  */
	public static Bitmap getReflectionImageWithOrigin(Bitmap bitmap) {
		
		// 原始图片和反射图片中间的间距
		final int reflectionGap = 0;
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		
		// 反转  
		Matrix matrix = new Matrix();
		
		// 第一个参数为1表示x方向上以原比例为准保持不变，正数表示方向不变。   
        // 第二个参数为-1表示y方向上以原比例为准保持不变，负数表示方向取反。
		matrix.preScale(1, -1);
		Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,
				width, height / 2, matrix, false);
		Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
				(height + height / 2), Config.ARGB_8888);
		Canvas canvas = new Canvas(bitmapWithReflection);
		canvas.drawBitmap(bitmap, 0, 0, null);
		Paint defaultPaint = new Paint();
		canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);
		canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
				bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
				0x00ffffff, TileMode.CLAMP);
		paint.setShader(shader);
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
				+ reflectionGap, paint);
		return bitmapWithReflection;
	}
}

在Activity中这样调用，先获取XML文件中定义的Imageview对象

image = (ImageView) findViewById(R.id.movie);

然后将获取到的Imageview对象转化为Bitmap类型

Bitmap imageBit = ((BitmapDrawable) image.getDrawable()).getBitmap();

接着调用图片工具类中的方法，返回一个Bitmap对象，将这个Bitmap对象放置在ImageView中

Bitmap m = ImageUtils.getReflectionImageWithOrigin(imageBit);
image.setImageBitmap(m);

第二种
继承ImageView类

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class ReflectImageView extends ImageView {

	private Bitmap originalBitmap;

	public ReflectImageView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

	public ReflectImageView(Context context) {
		this(context, null, 0);
	}

	public ReflectImageView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		DoReflection(((BitmapDrawable) getDrawable()).getBitmap());
	}

	@Override
	public void setImageBitmap(Bitmap bm) {
		DoReflection(bm);

	}

	/** 显示倒影效果的setImageBitmap函数 */
	public void setImageBitmap(Bitmap bm, boolean isFlected) {
		if (isFlected) {
			super.setImageBitmap(bm);
		}
	}

	@Override
	public void setImageResource(int resId) {

		originalBitmap = BitmapFactory.decodeResource(getResources(), resId);
		DoReflection(originalBitmap);
	}

	private void DoReflection(Bitmap bitmap) {
		final int reflectionGap = 0;
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		Matrix matrix = new Matrix();
		matrix.preScale(1, -1);
		Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,
				width, height / 2, matrix, false);
		Bitmap bitmap4Reflection = Bitmap.createBitmap(width,
				(height + height / 2), Config.ARGB_8888);
		Canvas canvasRef = new Canvas(bitmap4Reflection);
		Paint deafaultPaint = new Paint();
		deafaultPaint.setAntiAlias(true);
		canvasRef.drawBitmap(bitmap, 0, 0, null);
		canvasRef.drawRect(0, height, width, height + reflectionGap,
				deafaultPaint);
		canvasRef.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
				bitmap4Reflection.getHeight() + reflectionGap, 0x70ffffff,
				0x00ffffff, TileMode.CLAMP);
		paint.setShader(shader);
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		canvasRef.drawRect(0, height, width, bitmap4Reflection.getHeight()
				+ reflectionGap, paint);
		this.setImageBitmap(bitmap4Reflection, true);
	}

}

然后在xml文件里面配置

<com.hello.ReflectImageView
        android:id="@+id/imageView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@+drawable/button1" />

其中

com.hello.ReflectImageView

是继承类的完整包名