android 实现倒影

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首先，文章中出现的Gallery 已经不再适用，替代方法请看我的另一篇文章http://blog.csdn.net/xiangzhihong8/article/details/51120460

不过对于文章中说的倒影的原理是可以借鉴的。

1.图片的显示以及切换主要是自定义了一个Gallery

下面是代码myGallery.java：

[java] view
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import android.content.Context;
import android.graphics.Camera;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Transformation;
import android.widget.Gallery;
import android.widget.ImageView;
@SuppressWarnings("deprecation")
public class myGallery extends Gallery {
private Camera mCamera = new Camera();
private int mMaxRotationAngle = 60; //图片偏转角度 60
private int mMaxZoom = -120;
private int mCoveflowCenter;
public myGallery(Context context) {
super(context);
this.setStaticTransformationsEnabled(true);
}
public myGallery(Context context, AttributeSet attrs) {
super(context, attrs);
this.setStaticTransformationsEnabled(true);
}
public myGallery(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;
}
/** 获得Gallery中心到边界的距离*/
private int getCenterOfCoverflow() {
return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2 + getPaddingLeft();
}
/** 获得View中心位置到边界的距离 */
private static int getCenterOfView(View view) {
return view.getLeft() + view.getWidth() / 2;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mCoveflowCenter = getCenterOfCoverflow();
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected boolean getChildStaticTransformation(View child, Transformation trans) {
final int childCenter = getCenterOfView(child);
final int childWidth = child.getWidth();
int rotationAngle = 0;
trans.clear();
trans.setTransformationType(Transformation.TYPE_BOTH); // alpha和 matrix都变换
if (childCenter == mCoveflowCenter) { //正中间的childView
transformImageBitmap((ImageView) child, trans, 0);
} else { //两侧的childView
rotationAngle = (int) ( ( (float) (mCoveflowCenter - childCenter) / childWidth ) * mMaxRotationAngle );
if (Math.abs(rotationAngle) > mMaxRotationAngle) {
rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle;
}
transformImageBitmap((ImageView) child, trans, rotationAngle);
}
return true;
}
private void transformImageBitmap(ImageView child, Transformation trans, int rotationAngle) {
mCamera.save();
final Matrix imageMatrix = trans.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, 200.0f);
// 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);
}
mCamera.rotateY(rotationAngle); //rotationAngle 为正，沿y轴向内旋转；为负，沿y轴向外旋转
mCamera.getMatrix(imageMatrix);
imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));
mCamera.restore();
}
}

2.接下来就是要为图片添加倒影了，用过PhotoShop的都知道添加倒影就是将原有图片倒置，设置渐变式的显示，再将其放在原图片下面就行了，这里的方法也是一样

在为Gallery添加图片的同时，为每个图片添加倒影，需要在Adapter中做

下面就是相关代码 ImageAdapter.java：

[java] view
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import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.content.Context;
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.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
public class ImageAdapter extends BaseAdapter {
private ImageView[] mImages; // 存储每个图片的ImageView
private Context mContext;
public List<Map<String, Object>> list;
public Integer[] imgs = { R.drawable.img1, R.drawable.img2,
R.drawable.img3, R.drawable.img4, R.drawable.img5 };
public String[] titles = { "孙燕姿", "就是要唱歌", "微笑", "大海", "漂亮"};
public ImageAdapter(Context c) {
this.mContext = c;
list = new ArrayList<Map<String, Object>>();
for (int i = 0; i < imgs.length; i++) {
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("image", imgs[i]);
list.add(map);
}
mImages = new ImageView[list.size()];
}
/**
* 创建倒影效果
*/
@SuppressWarnings("deprecation")
public boolean createReflectedImages() {
final int reflectionGap = 4;//原图与倒影之间的间隙
int index = 0;
for (Map<String, Object> map : list) {
Integer id = (Integer) map.get("image");
Bitmap originalImage = BitmapFactory.decodeResource(
mContext.getResources(), id); // 获得图片资源
// 获得图片的长宽
int width = originalImage.getWidth();
int height = originalImage.getHeight();
Matrix matrix = new Matrix();
matrix.preScale(1, -1); // 实现图片的反转
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
height / 2, width, height / 2, matrix, false); // 创建反转后的图片Bitmap对象，图片高是原图的一半
Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888); // 创建标准的Bitmap对象，宽和原图一致，高是原图的1.5倍
Canvas canvas = new Canvas(bitmapWithReflection);
canvas.drawBitmap(originalImage, 0, 0, null); // 创建画布对象，将原图画于画布，起点是原点位置
Paint paint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, paint);
canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null); // 将反转后的图片画到画布中
paint = new Paint();
LinearGradient shader = new LinearGradient(0,
originalImage.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap,
0x70ffffff, 0x00ffffff, TileMode.MIRROR);// 创建线性渐变LinearGradient对象
paint.setShader(shader); // 绘制
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));//倒影遮罩效果
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint); // 画布画出反转图片大小区域，然后把渐变效果加到其中，就出现了图片的倒影效果
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection); // 设置带倒影的Bitmap
//设置ImageView的大小，可以根据图片大小设置
// imageView.setLayoutParams(newmyGallery.LayoutParams(width,height));
imageView.setLayoutParams(new myGallery.LayoutParams(250, 500));//设置ImageView的大小，可根据需要设置固定宽高
imageView.setScaleType(ScaleType.FIT_CENTER);//将图片按比例缩放
mImages[index++] = imageView;
}
return true;
}
@Override
public int getCount() {
return imgs.length;
}
@Override
public Object getItem(int position) {
return mImages[position];
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
return mImages[position]; // 获得Gallery中对应位置的ImageView
}
public float getScale(boolean focused, int offset) {
return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
}
}

3.然后在主Activity中进行配置Main.java：

[java] view
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import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;
public class Main extends Activity {
private TextView tvTitle;
private myGallery gallery;
private ImageAdapter adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initRes();
}
private void initRes(){
tvTitle = (TextView) findViewById(R.id.tvTitle);
gallery = (myGallery) findViewById(R.id.mygallery); // 获取自定义的myGallery控件
adapter = new ImageAdapter(this);
adapter.createReflectedImages(); // 创建倒影效果
gallery.setAdapter(adapter);
gallery.setOnItemSelectedListener(new OnItemSelectedListener() { // 设置选择事件监听
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
tvTitle.setText(adapter.titles[position]);
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
gallery.setOnItemClickListener(new OnItemClickListener() { // 设置点击事件监听
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(Main.this, "img " + (position+1) + " selected", Toast.LENGTH_SHORT).show();
}
});
}
}