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Android实现CoverFlow效果

發(fā)布時(shí)間：2025/4/16 Android 17 豆豆

生活随笔收集整理的這篇文章主要介紹了 Android实现CoverFlow效果小編覺得挺不錯(cuò)的,現(xiàn)在分享給大家,幫大家做個(gè)參考.

先上一張效果圖：

上代碼，看了代碼什么都明白

CoverFlow從Gallery繼承過來

view source print?

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	?????* 這就是所謂的在大小的布局時(shí),這一觀點(diǎn)已經(jīng)發(fā)生了改變。如果你只是添加到視圖層次,有人叫你舊的觀念價(jià)值觀為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	?????* 把圖像位圖的角度通過

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	????????// 如視圖的角度更少,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

}

這個(gè)就是CoverFlow類，說明幾點(diǎn)：
1. 成員函數(shù)
mCamera是用來做類3D效果處理,比如z軸方向上的平移,繞y軸的旋轉(zhuǎn)等
mMaxRotationAngle是圖片繞y軸最大旋轉(zhuǎn)角度,也就是屏幕最邊上那兩張圖片的旋轉(zhuǎn)角度
mMaxZoom是圖片在z軸平移的距離,視覺上看起來就是放大縮小的效果.
其他的變量都可以無視
也就是說把這個(gè)屬性設(shè)成true的時(shí)候每次viewGroup(看Gallery的源碼就可以看到它是從ViewGroup間接繼承過來的)在重新畫它的child的時(shí)候都會(huì)促發(fā)getChildStaticTransformation這個(gè)函數(shù),所以我們只需要在這個(gè)函數(shù)里面去加上旋轉(zhuǎn)和放大的操作就可以了
其他的getter和setter函數(shù)都可以無視

ImageAdapter適配器：

view source print?

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 Context mContext;

025	????private Integer[] mImageIds = {?

026	????????????R.drawable.a1,

027	????????????R.drawable.a2,?

028	????????????R.drawable.a3,

029	????????????R.drawable.a4,?

030	????????????R.drawable.a5 };

031

032	????public ImageAdapter(Context c) {

033	????????mContext = c;

034

????}

035

036	????public int getCount() {

037	????????return mImageIds.length;

038

????}

039

040	????public Object getItem(int position) {

041	????????return position;

042

????}

043

044	????public long getItemId(int position) {

045	????????return position;

046

????}

047

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

049

050	????????ImageView i = createReflectedImages(mContext,mImageIds[position]);

051	??????????

052	????????i.setLayoutParams(new CoverFlow.LayoutParams(120, 100));

053	????????i.setScaleType(ImageView.ScaleType.CENTER_INSIDE);

054	??????????

055	????????// 設(shè)置的抗鋸齒

056	????????BitmapDrawable drawable = (BitmapDrawable) i.getDrawable();

057	????????drawable.setAntiAlias(true);

058	????????return i;

059

????}

060

061	????public float getScale(boolean focused, int offset) {

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

063

????}

064

??????

065	????public ImageView createReflectedImages(Context mContext,int imageId) {

066

067	????????Bitmap originalImage = BitmapFactory.decodeResource(mContext.getResources(), imageId);

068	??????????

069	????????final int reflectionGap = 4;

070	??????????

071	????????int width = originalImage.getWidth();

072	????????int height = originalImage.getHeight();

073

074	????????Matrix matrix = new Matrix();

075	????????matrix.preScale(1, -1);

076

077	????????Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,

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

079

080	????????Bitmap bitmapWithReflection = Bitmap.createBitmap(width,

081	????????????????(height + height / 2), Config.ARGB_8888);

082

083	????????Canvas canvas = new Canvas(bitmapWithReflection);

084

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

086

087	????????Paint deafaultPaint = new Paint();

088	????????canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint);

089

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

091

092	????????Paint paint = new Paint();

093	????????LinearGradient shader = new LinearGradient(0, originalImage

094	????????????????.getHeight(), 0, bitmapWithReflection.getHeight()

095	????????????????+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.MIRROR);

096

097	????????paint.setShader(shader);

098

099	????????paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));

100

101	????????canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()

102	????????????????+ reflectionGap, paint);

103

104	????????ImageView imageView = new ImageView(mContext);

105	????????imageView.setImageBitmap(bitmapWithReflection);

106

107	????????return imageView;

108

????}

109

??????

110

}

BitmapDrawable drawable = (BitmapDrawable) i.getDrawable();
drawable.setAntiAlias(true);
是保證圖片繞Y旋轉(zhuǎn)了以后不會(huì)出現(xiàn)鋸齒.

下面是Activity：

view source print?

01	package com.coverflow;

03	import android.app.Activity;

04	import android.graphics.Color;

05	import android.os.Bundle;

07	import com.gallery.R;

09	public class HelloAndroid extends Activity {

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

11	????@Override

12	????public void onCreate(Bundle savedInstanceState) {

13	????????super.onCreate(savedInstanceState);

15	????????CoverFlow cf = new CoverFlow(this);

16	????????// cf.setBackgroundResource(R.drawable.shape);

17	????????cf.setBackgroundColor(Color.BLACK);

18	????????cf.setAdapter(new ImageAdapter(this));

19	????????ImageAdapter imageAdapter = new ImageAdapter(this);

20	????????cf.setAdapter(imageAdapter);

21	????????// cf.setAlphaMode(false);

22	????????// cf.setCircleMode(false);

23	????????cf.setSelection(2, true);

24	????????cf.setAnimationDuration(1000);

25	????????setContentView(cf);

????}

}

參考自：
http://www.eoeandroid.com/thread-70209-1-1.html
http://www.apkbus.com/android-18441-1-1.html

轉(zhuǎn)載于:https://www.cnblogs.com/ou10209019/archive/2012/07/30/2615861.html

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