Android开发教程:倒影效果的ImagView
Android开发教程:倒影效果的ImagView
效果图如下:
代码如下:
- package lab.sodino.reflection;
- 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.graphics.drawable.BitmapDrawable;
- import android.util.AttributeSet;
- import android.widget.ImageView;
- public class ReflectionImage extends ImageView {
- // 是否为Reflection模式
- private boolean mReflectionMode = true;
- public ReflectionImage(Context context) {
- super(context);
- }
- public ReflectionImage(Context context, AttributeSet attrs) {
- super(context, attrs);
- measure(0, 0);
- // 取得原始图片的bitmap并重画
- Bitmap originalImage = ((BitmapDrawable) this.getDrawable()).getBitmap();
- DoReflection(originalImage);
- }
- public ReflectionImage(Context context, AttributeSet attrs, int defStyle) {
- super(context, attrs, defStyle);
- Bitmap originalImage = ((BitmapDrawable) this.getDrawable()).getBitmap();
- DoReflection(originalImage);
- }
- public void setReflectionMode(boolean isRef) {
- mReflectionMode = isRef;
- }
- public boolean getReflectionMode() {
- return mReflectionMode;
- }
- // 偷懒了,只重写了setImageResource,和构造函数里面干了同样的事情
- @Override
- public void setImageResource(int resId) {
- Bitmap originalImage = BitmapFactory.decodeResource(getResources(), resId);
- DoReflection(originalImage);
- // super.setImageResource(resId);
- }
- private void DoReflection(Bitmap originalImage) {
- // 原始图片和反射图片中间的间距
- final int reflectionGap = 4;
- int width = originalImage.getWidth();
- int height = originalImage.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, -0.75f);
- // reflectionImage就是下面透明的那部分,可以设置它的高度为原始的3/4,这样效果会更好些
- Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, 0, width, height * 3 / 4, matrix, false);
- // 创建一个新的bitmap,高度为原来的两倍
- Bitmap bitmap4Reflection = Bitmap.createBitmap(width, (height + height * 3 / 4), Config.ARGB_8888);
- // 其宽*高 = width * (height + height * 3 / 4)
- Canvas canvasRef = new Canvas(bitmap4Reflection);
- // 先画原始的图片
- canvasRef.drawBitmap(originalImage, 0, 0, null);
- // 画间距
- Paint deafaultPaint = new Paint();
- // defaultPaint不能为null,否则会有空指针异常。
- canvasRef.drawRect(0, height, width, height + reflectionGap, deafaultPaint);
- // 画被反转以后的图片
- canvasRef.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
- // 创建一个渐变的蒙版放在下面被反转的图片上面
- Paint paint = new Paint();
- LinearGradient shader = new LinearGradient(200, originalImage.getHeight(), 10, bitmap4Reflection.getHeight()
- + reflectionGap, 0x80ffffff, 0x00ffffff, TileMode.CLAMP);
- paint.setShader(shader);
- // Set the Transfer mode to be porter duff and destination in
- paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
- // 将蒙板画上
- canvasRef.drawRect(0, height, width, bitmap4Reflection.getHeight() + reflectionGap, paint);
- // 调用ImageView中的setImageBitmap
- this.setImageBitmap(bitmap4Reflection);
- }
- }
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