Android Gallary图片游览效果--透明的倒影，层叠的图片，渐变的颜色透明度

下面，是我参照他的博客实现的一个效果图。这个程序，在他的基础上进行了一些改良，但改良得不是很好，嘻嘻，等有空，继续研究。该实

下载路径：http://download.csdn.net/detail/heng615975867/6451947

（一）截图



（二）实现关键：

1、改写Gallery，实现图片的层叠和透明度渐变。 主要是改写getChildStaticTransformation方法

2、对图片进行加工处理，实现透明倒影。

3、对于超大图片，先进行缩小。防止图片过大，超出屏幕范围报错。

（三）代码

1、Activity类代码：GallaryBrowser.java

[java] view
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package com.myandroid.test;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.ImageSwitcher;

import android.widget.ImageView;

import android.widget.Gallery.LayoutParams;

import android.widget.ViewSwitcher.ViewFactory;

public class GallaryBrowser extends Activity {

private Integer[] imageIds = new Integer[] {

R.drawable.a, R.drawable.desert,

R.drawable.hydrangeas, R.drawable.lighthouse,

R.drawable.jellyfish, R.drawable.koala,

R.drawable.lighthouse, R.drawable.penguins,

R.drawable.tulips

};

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

final CoverFlow cf = new CoverFlow(this);

cf.setAdapter(new ImageAdapter(this, imageIds));

cf.setAnimationDuration(1500);

setContentView(cf);

}

}

2、图片处理代码，主要是实现旋转和倒影： MyImgView.java

[java] view
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///******************************************************************************//

///**************************请尊重tank的成果毕竟这也是花了笔者很多时间和心思*****//

/************************* 为了让大家容易懂tank特地详细的写了很多的解释*********************************************////

///**************************欢迎访问我的博客http://www.cnblogs.com/tankaixiong/********************************************//

///***************************里面文章将持续更新！***************************************************//

package com.myandroid.test;

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.LinearGradient;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.PixelFormat;

import android.graphics.PorterDuffXfermode;

import android.graphics.Bitmap.Config;

import android.graphics.PorterDuff.Mode;

import android.graphics.Shader.TileMode;

import android.graphics.drawable.Drawable;

public class MyImgView {

/**

* 添加倒影，原理，先翻转图片，由上到下放大透明度

*

* @param originalImage

* @return

*/

public static Bitmap createReflectedImage(Bitmap originalImage) {

// The gap we want between the reflection and the original image

final int reflectionGap = 4;

int width = originalImage.getWidth();

int height = originalImage.getHeight();

// This will not scale but will flip on the Y axis

Matrix matrix = new Matrix();

matrix.preScale(1, -1);

// Create a Bitmap with the flip matrix applied to it.

// We only want the bottom half of the image

Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,

height / 2, width, height / 2, matrix, false);

// Create a new bitmap with same width but taller to fit reflection

Bitmap bitmapWithReflection = Bitmap.createBitmap(width,

(height + height / 2), Config.ARGB_8888);

// Create a new Canvas with the bitmap that's big enough for

// the image plus gap plus reflection

Canvas canvas = new Canvas(bitmapWithReflection);

// Draw in the original image

canvas.drawBitmap(originalImage, 0, 0, null);

// Draw in the gap

Paint defaultPaint = new Paint();

canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);

// Draw in the reflection

canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

// Create a shader that is a linear gradient that covers the reflection

Paint paint = new Paint();

LinearGradient shader = new LinearGradient(0,

originalImage.getHeight(), 0, bitmapWithReflection.getHeight()

+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);

// Set the paint to use this shader (linear gradient)

paint.setShader(shader);

// Set the Transfer mode to be porter duff and destination in

paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));

// Draw a rectangle using the paint with our linear gradient

canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()

+ reflectionGap, paint);

return bitmapWithReflection;

}

//drawable 类型转化为bitmap

public static Bitmap drawableToBitmap(Drawable drawable) {

Bitmap bitmap = Bitmap

.createBitmap(

drawable.getIntrinsicWidth(),

drawable.getIntrinsicHeight(),

drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888

: Bitmap.Config.RGB_565);

Canvas canvas = new Canvas(bitmap);

// canvas.setBitmap(bitmap);

drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable

.getIntrinsicHeight());

drawable.draw(canvas);

return bitmap;

}

}

3、自定义的Gallery，继承Gallery类,重写getChildStaticTransformation方法，实现图片的重叠和透明度渐变：CoverFlow.java

[java] view
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///******************************************************************************//

///**************************请尊重tank的成果毕竟这也是花了笔者很多时间和心思*****//

/************************* 为了让大家容易懂tank特地详细的写了很多的解释*********************************************////

///**************************欢迎访问我的博客http://www.cnblogs.com/tankaixiong/********************************************//

///***************************里面文章将持续更新！***************************************************//

package com.myandroid.test;

import android.content.Context;

import android.graphics.Camera;

import android.graphics.Matrix;

import android.util.AttributeSet;

import android.util.Log;

import android.view.View;

import android.view.animation.Transformation;

import android.widget.Gallery;

import android.widget.ImageView;

//自己定义的Gallery

public class CoverFlow extends Gallery {

private Camera mCamera = new Camera();

private int mMaxRotationAngle = 50;

private int mMaxZoom = -500;

private int mCoveflowCenter;

private boolean mAlphaMode = true;

private boolean mCircleMode = false;

public CoverFlow(Context context) {

super(context);

this.setStaticTransformationsEnabled(true);

Log.e("sequence", "CoverFlow2");

}

public CoverFlow(Context context, AttributeSet attrs) {

super(context, attrs);

this.setStaticTransformationsEnabled(true);

}

public CoverFlow(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

this.setStaticTransformationsEnabled(true);

}

public int getMaxRotationAngle() {

return mMaxRotationAngle;

}

public void setMaxRotationAngle(int maxRotationAngle) {

mMaxRotationAngle = maxRotationAngle;

}

public boolean getCircleMode() {

return mCircleMode;

}

public void setCircleMode(boolean isCircle) {

mCircleMode = isCircle;

}

public boolean getAlphaMode() {

return mAlphaMode;

}

public void setAlphaMode(boolean isAlpha) {

mAlphaMode = isAlpha;

}

public int getMaxZoom() {

return mMaxZoom;

}

public void setMaxZoom(int maxZoom) {

mMaxZoom = maxZoom;

}

private int getCenterOfCoverflow() {

return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2

+ getPaddingLeft();

}

private static int getCenterOfView(View view) {

return view.getLeft() + view.getWidth() / 2;

}

//重写Garray方法 ，产生层叠和放大效果

@Override

protected boolean getChildStaticTransformation(View child, Transformation t) {

final int childCenter = getCenterOfView(child);

final int childWidth = child.getWidth();

int rotationAngle = 0;

t.clear();

t.setTransformationType(Transformation.TYPE_MATRIX);

if (childCenter == mCoveflowCenter) {

transformImageBitmap((ImageView) child, t, 0, 0);

} else {

rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);

// Log.d("test", "recanglenum:"+Math.floor ((mCoveflowCenter -

// childCenter) / childWidth));

if (Math.abs(rotationAngle) > mMaxRotationAngle) {

rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle

: mMaxRotationAngle;

}

transformImageBitmap((ImageView) child, t, rotationAngle,

(int) Math.floor((mCoveflowCenter - childCenter)/ (childWidth==0?1:childWidth)));

}

Log.e("sequence", "getChildStaticTransformation");

return true;

}

/**

* This is called during layout when the size of this view has changed. If

* you were just added to the view hierarchy, you're called with the old

* values of 0.

*

* @param w

* Current width of this view.

* @param h

* Current height of this view.

* @param oldw

* Old width of this view.

* @param oldh

* Old height of this view.

*/

protected void onSizeChanged(int w, int h, int oldw, int oldh) {

mCoveflowCenter = getCenterOfCoverflow();

super.onSizeChanged(w, h, oldw, oldh);

Log.e("sequence", "onSizeChanged");

}

/**

* Transform the Image Bitmap by the Angle passed

*

* @param imageView

* ImageView the ImageView whose bitmap we want to rotate

* @param t

* transformation

* @param rotationAngle

* the Angle by which to rotate the Bitmap

*/

private void transformImageBitmap(ImageView child, Transformation t,

int rotationAngle, int d) {

mCamera.save();

final Matrix imageMatrix = t.getMatrix();

final int imageHeight = child.getLayoutParams().height;

final int imageWidth = child.getLayoutParams().width;

final int rotation = Math.abs(rotationAngle);

mCamera.translate(0.0f, 0.0f, 100.0f);

// As the angle of the view gets less, zoom in

if (rotation <= mMaxRotationAngle) {

float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));

mCamera.translate(0.0f, 0.0f, zoomAmount);

if (mCircleMode) {

if (rotation < 40)

mCamera.translate(0.0f, 155, 0.0f);

else

mCamera.translate(0.0f, (255 - rotation * 2.5f), 0.0f);

}

if (mAlphaMode) {

((ImageView) (child)).setAlpha((int) (255 - rotation * 2.5));

}

}

mCamera.rotateY(rotationAngle);

mCamera.getMatrix(imageMatrix);

imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));

imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));

mCamera.restore();

Log.e("sequence", "transformImageBitmap");

}

}

4、图片适配器：ImageAdapter。这里，我改写了getView方法，把图片按照一定比例进行缩放，防止图片过大，超出屏幕而导致报错。

[java] view
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package com.myandroid.test;

import java.io.InputStream;

import android.content.Context;

import android.content.res.Resources;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Matrix;

import android.graphics.drawable.BitmapDrawable;

import android.view.View;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.Gallery;

import android.widget.ImageView;

public class ImageAdapter extends BaseAdapter {

private Context context;

private Integer[] images;

public ImageAdapter(Context context, Integer[] imageIds) {

this.context = context;

this.images = imageIds;

}

@Override

public int getCount() {

// TODO Auto-generated method stub

return images.length;

}

@Override

public Object getItem(int position) {

// TODO Auto-generated method stub

return position;

}

@Override

public long getItemId(int position) {

// TODO Auto-generated method stub

return position;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

ImageView imageView = new ImageView(context);

//创建BitMap对象，用于显示图片

Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),

images[position]);

Matrix matrix = new Matrix(); //矩阵，用于图片比例缩放

matrix.postScale((float)80/bitmap.getWidth(),

(float)60/bitmap.getHeight()); //设置高宽比例（三维矩阵）

//图片不能超出屏幕范围，否则报错，这里进行缩小

Bitmap newBmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),

bitmap.getHeight(), matrix, true);

imageView.setImageBitmap(MyImgView.createReflectedImage(newBmp));

imageView.setLayoutParams(new Gallery.LayoutParams(80, 60));

return imageView;

}

}