Android Gallery控件使用方法详解

我们今天给大家讲的就是Gallery控件，这个控件在android当中是非常重要的，我们今天就给大家介绍一下3D的Gallery控件是怎么样来实现的。下面我们就来直接看看代码吧。

1.扩展Gallery：

public class GalleryFlow extends Gallery {private Camera mCamera = new Camera();//相机类private int mMaxRotationAngle = 60;//最大转动角度private int mMaxZoom = -300;////最大缩放值private int mCoveflowCenter;//半径值public GalleryFlow(Context context) {super(context);//支持转换 ,执行getChildStaticTransformation方法this.setStaticTransformationsEnabled(true);}public GalleryFlow(Context context, AttributeSet attrs) {super(context, attrs);this.setStaticTransformationsEnabled(true);}public GalleryFlow(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) {System.out.println("view left :"+view.getLeft());System.out.println("view width :"+view.getWidth());return view.getLeft() + view.getWidth() / 2;}//控制gallery中每个图片的旋转(重写的gallery中方法)protected boolean getChildStaticTransformation(View child, Transformation t) { //取得当前子view的半径值final int childCenter = getCenterOfView(child);System.out.println("childCenter："+childCenter);final int childWidth = child.getWidth();//旋转角度int rotationAngle = 0;//重置转换状态t.clear();//设置转换类型t.setTransformationType(Transformation.TYPE_MATRIX);//如果图片位于中心位置不需要进行旋转if (childCenter == mCoveflowCenter) {transformImageBitmap((ImageView) child, t, 0);} else {//根据图片在gallery中的位置来计算图片的旋转角度rotationAngle = (int) (((float) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle);System.out.println("rotationAngle:" +rotationAngle);//如果旋转角度绝对值大于最大旋转角度返回（-mMaxRotationAngle或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) {//对效果进行保存mCamera.save();final Matrix imageMatrix = t.getMatrix();//图片高度final int imageHeight = child.getLayoutParams().height;//图片宽度final int imageWidth = child.getLayoutParams().width;//返回旋转角度的绝对值final int rotation = Math.abs(rotationAngle);// 在Z轴上正向移动camera的视角，实际效果为放大图片。// 如果在Y轴上移动，则图片上下移动；X轴上对应图片左右移动。mCamera.translate(0.0f, 0.0f, 100.0f);// As the angle of the view gets less, zoom inif (rotation < mMaxRotationAngle) {float zoomAmount = (float) (mMaxZoom + (rotation * 1.5));mCamera.translate(0.0f, 0.0f, zoomAmount);}// 在Y轴上旋转，对应图片竖向向里翻转。// 如果在X轴上旋转，则对应图片横向向里翻转。mCamera.rotateY(rotationAngle);mCamera.getMatrix(imageMatrix);imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));mCamera.restore();}}

2.填充图片容器(BaseAdapter):

public class ImageAdapter extends BaseAdapter {int mGalleryItemBackground;private Context mContext;private Integer[] mImageIds;private ImageView[] mImages;public ImageAdapter(Context c, Integer[] ImageIds) {mContext = c;mImageIds = ImageIds;mImages = new ImageView[mImageIds.length];}/*** 创建倒影效果* @return*/public boolean createReflectedImages() {//倒影图和原图之间的距离final int reflectionGap = 4;int index = 0;for (int imageId : mImageIds) {//返回原图解码之后的bitmap对象Bitmap originalImage = BitmapFactory.decodeResource(mContext.getResources(), imageId);int width = originalImage.getWidth();int height = originalImage.getHeight();//创建矩阵对象Matrix matrix = new Matrix();//指定一个角度以0,0为坐标进行旋转// matrix.setRotate(30);//指定矩阵(x轴不变，y轴相反)matrix.preScale(1, -1);//将矩阵应用到该原图之中，返回一个宽度不变，高度为原图1/2的倒影位图Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,height/2, width, height/2, matrix, false);//创建一个宽度不变，高度为原图+倒影图高度的位图Bitmap bitmapWithReflection = Bitmap.createBitmap(width,(height + height / 2), Config.ARGB_8888);//将上面创建的位图初始化到画布Canvas canvas = new Canvas(bitmapWithReflection);canvas.drawBitmap(originalImage, 0, 0, null);Paint deafaultPaint = new Paint(); deafaultPaint.setAntiAlias(false);// canvas.drawRect(0, height, width, height + reflectionGap,deafaultPaint);canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);Paint paint = new Paint();paint.setAntiAlias(false);/*** 参数一:为渐变起初点坐标x位置，* 参数二:为y轴位置，* 参数三和四:分辨对应渐变终点，* 最后参数为平铺方式，* 这里设置为镜像Gradient是基于Shader类，所以我们通过Paint的setShader方法来设置这个渐变*/LinearGradient shader = new LinearGradient(0,originalImage.getHeight(), 0,bitmapWithReflection.getHeight() + reflectionGap,0x70ffffff, 0x00ffffff, TileMode.MIRROR);//设置阴影paint.setShader(shader);paint.setXfermode(new PorterDuffXfermode(android.graphics.PorterDuff.Mode.DST_IN));//用已经定义好的画笔构建一个矩形阴影渐变效果canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()+ reflectionGap, paint);//创建一个ImageView用来显示已经画好的bitmapWithReflectionImageView imageView = new ImageView(mContext);imageView.setImageBitmap(bitmapWithReflection);//设置imageView大小 ，也就是最终显示的图片大小imageView.setLayoutParams(new GalleryFlow.LayoutParams(300, 400));//imageView.setScaleType(ScaleType.MATRIX);mImages[index++] = imageView;}return true;}@SuppressWarnings("unused")private Resources getResources() {return null;}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)));}}

3.创建Activity:

public class Gallery3DActivity extends Activity {public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.layout_gallery);Integer[] images = { R.drawable.img0001, R.drawable.img0030,R.drawable.img0100, R.drawable.img0130, R.drawable.img0200,R.drawable.img0230, R.drawable.img0330,R.drawable.img0354 };ImageAdapter adapter = new ImageAdapter(this, images);adapter.createReflectedImages();//创建倒影效果GalleryFlow galleryFlow = (GalleryFlow) this.findViewById(R.id.Gallery01);galleryFlow.setFadingEdgeLength(0);galleryFlow.setSpacing(-100); //图片之间的间距galleryFlow.setAdapter(adapter);galleryFlow.setOnItemClickListener(new OnItemClickListener() {public void onItemClick(AdapterView<?> parent, View view,int position, long id) {Toast.makeText(getApplicationContext(), String.valueOf(position), Toast.LENGTH_SHORT).show();}});galleryFlow.setSelection(4);}}

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