图片左右滚动控件（带倒影）——重写Gallery

今天在网上找了些资料，做了一个图片左右滚动的Demo，类似幻灯片播放，同时，图片带倒影效果，运行效果如下图：




实现方式是重写Gallery，使用自定义的Gallery来实现这一效果，工程一共三个文件，一个Activity，一个自定义的Gallery，还有就是一个适配器ImageAdapter，直接上代码：

ScrollGallery.java

[java] view
plaincopy

public class ScrollGallery extends Gallery {

private Camera mCamera = new Camera();

//左右图片倾斜的角度

private int mMaxRotationAngle = 60;

//背景区域大小

private int mMaxZoom = -380;

private int mCoveflowCenter;



public ScrollGallery(Context context) {

super(context);

this.setStaticTransformationsEnabled(true);

}



public ScrollGallery(Context context, AttributeSet attrs) {

super(context, attrs);

this.setStaticTransformationsEnabled(true);

}



public ScrollGallery(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 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;

}



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);

} else {

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

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

rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle

: mMaxRotationAngle;

}

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

}

return true;

}



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

mCoveflowCenter = getCenterOfCoverflow();

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

}



private void transformImageBitmap(ImageView child, Transformation t,

int rotationAngle) {

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);

// 在Z轴上正向移动

// 在Y轴上移动，上下移动；X轴上左右移动。

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

if (rotation < mMaxRotationAngle) {

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

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

}

// 在Y轴上旋转，竖向向里翻转。

// 在X轴上旋转，则横向向里翻转。

mCamera.rotateY(rotationAngle);

mCamera.getMatrix(imageMatrix);

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

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

mCamera.restore();

}

}

ImageAdapter.java

[java] view
plaincopy

public class ImageAdapter extends BaseAdapter {

//倒影的缩放比例

private static final int REFLECTION = 5;



int mGalleryItemBackground;

private Context mContext;

private int[] mImageIds;

private ImageView[] mImages;



public ImageAdapter(Context c, int[] ImageIds) {

mContext = c;

mImageIds = ImageIds;

mImages = new ImageView[mImageIds.length];

}



public boolean createReflectedImages() {

final int reflectionGap = 5;

int index = 0;

for (int imageId : mImageIds) {

Bitmap originalImage = BitmapFactory.decodeResource(

mContext.getResources(), imageId);

int width = originalImage.getWidth();

int height = originalImage.getHeight();

Matrix matrix = new Matrix();

matrix.preScale(1, -1);

Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,

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

Bitmap bitmapWithReflection = Bitmap.createBitmap(width,

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

Canvas canvas = new Canvas(bitmapWithReflection);

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

Paint deafaultPaint = new Paint();

canvas.drawRect(0, height, width, height + reflectionGap,

deafaultPaint);

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

Paint paint = new Paint();

LinearGradient shader = new LinearGradient(0,

originalImage.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);

ImageView imageView = new ImageView(mContext);

imageView.setImageBitmap(bitmapWithReflection);

imageView.setLayoutParams(new ScrollGallery.LayoutParams(180, 240));

mImages[index++] = imageView;

}

return true;

}



public int getCount() {

return mImageIds.length;

}



public Object getItem(int position) {

return position;

}



public long getItemId(int position) {

return position;

}



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

return mImages[position];

}



public float getScale(boolean focused, int offset) {

return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));

}

}

ScrollImageActivity.java

[java] view
plaincopy

public class ScrollImageActivity extends Activity {

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



private ScrollGallery galleryFlow = null;



int images[] = {R.drawable.a,R.drawable.b,R.drawable.c,R.drawable.d,R.drawable.f};



@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

requestWindowFeature(Window.FEATURE_NO_TITLE);

setContentView(R.layout.main);

galleryFlow = (ScrollGallery) this.findViewById(R.id.gf_images);

ImageAdapter adapter = new ImageAdapter(this, images);

adapter.createReflectedImages();

galleryFlow.setAdapter(adapter);

galleryFlow.setSelection(1);

}

}

main.xml

[html] view
plaincopy

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" >



<com.ryan.scrollimage.ScrollGallery

android:id="@+id/gf_images"

android:layout_width="fill_parent"

android:layout_height="0dip"

android:layout_weight="1" />



</LinearLayout>

来源：/article/1650634.html