Android实现CoverFlow效果
16lz
2021-12-04
Android实现CoverFlow效果
先上一张效果图:
CoverFlow从Gallery继承过来
001 | package com.coverflow; |
002 |
003 | import android.content.Context; |
004 | import android.graphics.Camera; |
005 | import android.graphics.Matrix; |
006 | import android.util.AttributeSet; |
007 | import android.view.View; |
008 | import android.view.animation.Transformation; |
009 | import android.widget.Gallery; |
010 | import android.widget.ImageView; |
011 |
012 | public class CoverFlow extends Gallery { |
013 |
014 | private Camera mCamera = new Camera(); |
015 | private int mMaxRotationAngle = 50 ; |
016 | private int mMaxZoom = - 380 ; |
017 | private int mCoveflowCenter; |
018 | private boolean mAlphaMode = true ; |
019 | private boolean mCircleMode = false ; |
020 |
021 | public CoverFlow(Context context) { |
022 | super (context); |
023 | this .setStaticTransformationsEnabled( true ); |
024 | } |
025 |
026 | public CoverFlow(Context context, AttributeSet attrs) { |
027 | super (context, attrs); |
028 | this .setStaticTransformationsEnabled( true ); |
029 | } |
030 |
031 | public CoverFlow(Context context, AttributeSet attrs, int defStyle) { |
032 | super (context, attrs, defStyle); |
033 | this .setStaticTransformationsEnabled( true ); |
034 | } |
035 |
036 | public int getMaxRotationAngle() { |
037 | return mMaxRotationAngle; |
038 | } |
039 |
040 | public void setMaxRotationAngle( int maxRotationAngle) { |
041 | mMaxRotationAngle = maxRotationAngle; |
042 | } |
043 |
044 | public boolean getCircleMode() { |
045 | return mCircleMode; |
046 | } |
047 |
048 | public void setCircleMode( boolean isCircle) { |
049 | mCircleMode = isCircle; |
050 | } |
051 |
052 | public boolean getAlphaMode() { |
053 | return mAlphaMode; |
054 | } |
055 |
056 | public void setAlphaMode( boolean isAlpha) { |
057 | mAlphaMode = isAlpha; |
058 | } |
059 |
060 | public int getMaxZoom() { |
061 | return mMaxZoom; |
062 | } |
063 |
064 | public void setMaxZoom( int maxZoom) { |
065 | mMaxZoom = maxZoom; |
066 | } |
067 |
068 | private int getCenterOfCoverflow() { |
069 | return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2 |
070 | + getPaddingLeft(); |
071 | } |
072 |
073 | private static int getCenterOfView(View view) { |
074 | return view.getLeft() + view.getWidth() / 2 ; |
075 | } |
076 |
077 | protected boolean getChildStaticTransformation(View child, Transformation t) { |
078 | final int childCenter = getCenterOfView(child); |
079 | final int childWidth = child.getWidth(); |
080 | int rotationAngle = 0 ; |
081 | t.clear(); |
082 | t.setTransformationType(Transformation.TYPE_MATRIX); |
083 | if (childCenter == mCoveflowCenter) { |
084 | transformImageBitmap((ImageView) child, t, 0 ); |
085 | } else { |
086 | rotationAngle = ( int ) ((( float ) (mCoveflowCenter - childCenter) / childWidth) * mMaxRotationAngle); |
087 | if (Math.abs(rotationAngle) > mMaxRotationAngle) { |
088 | rotationAngle = (rotationAngle < 0 ) ? -mMaxRotationAngle |
089 | : mMaxRotationAngle; |
090 | } |
091 | transformImageBitmap((ImageView) child, t, rotationAngle); |
092 | } |
093 | return true ; |
094 | } |
095 |
096 | /** |
097 | * 这就是所谓的在大小的布局时,这一观点已经发生了改变。如果 你只是添加到视图层次,有人叫你旧的观念 价值观为0。 |
098 | * |
099 | * @param w |
100 | * Current width of this view. |
101 | * @param h |
102 | * Current height of this view. |
103 | * @param oldw |
104 | * Old width of this view. |
105 | * @param oldh |
106 | * Old height of this view. |
107 | */ |
108 | protected void onSizeChanged( int w, int h, int oldw, int oldh) { |
109 | mCoveflowCenter = getCenterOfCoverflow(); |
110 | super .onSizeChanged(w, h, oldw, oldh); |
111 | } |
112 |
113 | /** |
114 | * 把图像位图的角度通过 |
115 | * |
116 | * @param imageView |
117 | * ImageView the ImageView whose bitmap we want to rotate |
118 | * @param t |
119 | * transformation |
120 | * @param rotationAngle |
121 | * the Angle by which to rotate the Bitmap |
122 | */ |
123 | private void transformImageBitmap(ImageView child, Transformation t, |
124 | int rotationAngle) { |
125 | mCamera.save(); |
126 | final Matrix imageMatrix = t.getMatrix(); |
127 | final int imageHeight = child.getLayoutParams().height; |
128 | final int imageWidth = child.getLayoutParams().width; |
129 | final int rotation = Math.abs(rotationAngle); |
130 | mCamera.translate( 0 .0f, 0 .0f, 100 .0f); |
131 |
132 | // 如视图的角度更少,放大 |
133 | if (rotation <= mMaxRotationAngle) { |
134 | float zoomAmount = ( float ) (mMaxZoom + (rotation * 1.5 )); |
135 | mCamera.translate( 0 .0f, 0 .0f, zoomAmount); |
136 | if (mCircleMode) { |
137 | if (rotation < 40 ) |
138 | mCamera.translate( 0 .0f, 155 , 0 .0f); |
139 | else |
140 | mCamera.translate( 0 .0f, ( 255 - rotation * 2 .5f), 0 .0f); |
141 | } |
142 | if (mAlphaMode) { |
143 | ((ImageView) (child)).setAlpha(( int ) ( 255 - rotation * 2.5 )); |
144 | } |
145 | } |
146 | mCamera.rotateY(rotationAngle); |
147 | mCamera.getMatrix(imageMatrix); |
148 | imageMatrix.preTranslate(-(imageWidth / 2 ), -(imageHeight / 2 )); |
149 | imageMatrix.postTranslate((imageWidth / 2 ), (imageHeight / 2 )); |
150 | mCamera.restore(); |
151 | } |
152 | } |
这个就是CoverFlow类,说明几点:
1. 成员函数
mCamera是用来做类3D效果处理,比如z轴方向上的平移,绕y轴的旋转等
mMaxRotationAngle是图片绕y轴最大旋转角度,也就是屏幕最边上那两张图片的旋转角度
mMaxZoom是图片在z轴平移的距离,视觉上看起来就是放大缩小的效果.
其他的变量都可以无视
也就是说把这个属性设成true的时候每次viewGroup(看Gallery的源码就可以看到它是从ViewGroup间接继承过来的)在重新画它的child的时候都会促发getChildStaticTransformation这个函数,所以我们只需要在这个函数里面去加上旋转和放大的操作就可以了
其他的getter和setter函数都可以无视
ImageAdapter适配器:
001 | package com.coverflow; |
002 |
003 | import android.content.Context; |
004 | import android.graphics.Bitmap; |
005 | import android.graphics.BitmapFactory; |
006 | import android.graphics.Canvas; |
007 | import android.graphics.LinearGradient; |
008 | import android.graphics.Matrix; |
009 | import android.graphics.Paint; |
010 | import android.graphics.PorterDuffXfermode; |
011 | import android.graphics.Bitmap.Config; |
012 | import android.graphics.PorterDuff.Mode; |
013 | import android.graphics.Shader.TileMode; |
014 | import android.graphics.drawable.BitmapDrawable; |
015 | import android.view.View; |
016 | import android.view.ViewGroup; |
017 | import android.widget.BaseAdapter; |
018 | import android.widget.ImageView; |
019 |
020 | import com.gallery.R; |
021 |
022 | public class ImageAdapter extends BaseAdapter { |
023 | int mGalleryItemBackground; |
024 | private |
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