coverflow android：如何从coverflow中的url获取图像
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【中文标题】coverflow android：如何从coverflow中的url获取图像【英文标题】：coverflow android :how to get images from a url in the coverflow 【发布时间】：2012-07-26 21:14:14 【问题描述】：嗨，我目前正在测试 android coverflow 我试图从 url 获取图像并将其显示在封面流中 我已成功下载图像但无法放入位图。 这是我尝试过的代码...
package com.example.coverflow;
import java.io.FileInputStream;
import android.app.Activity;
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.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.ImageView.ScaleType;
import com.example.coverflow.CoverAdapterView.OnItemClickListener;
public class CoverFlowExample extends Activity
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
CoverFlow coverFlow;
coverFlow = new CoverFlow(this);
coverFlow.setAdapter(new ImageAdapter(this));
ImageAdapter coverImageAdapter = new ImageAdapter(this);
coverImageAdapter.createReflectedImages();
coverFlow.setAdapter(coverImageAdapter);
coverFlow.setSpacing(-15);
coverFlow.setSelection(8, true);
setContentView(coverFlow);
coverFlow.setOnItemClickListener(new OnItemClickListener()
@Override
public void onItemClick(CoverAdapterView<?> parent, View view,
int position, long id)
// TODO Auto-generated method stub
Log.v("possition ", " this position :"+position );
Toast.makeText(getApplicationContext(), "position "+position, Toast.LENGTH_SHORT).show();
);
// Use this if you want to use XML layout file
// setContentView(R.layout.main);
// coverFlow = (CoverFlow) findViewById(R.id.coverflow);
public class ImageAdapter extends BaseAdapter
int mGalleryItemBackground;
private Context mContext;
private FileInputStream fis;
//public Integer[] mImageIds ;
private Integer[] mImageIds =1,2,3,4,5;
/*private Integer[] mImageIds = R.drawable.kas***_kas***,
R.drawable.killers_day_and_age, R.drawable.garbage_bleed_like_me,
R.drawable.death_cub_for_cutie_the_photo_album,
R.drawable.kas***_kas***, R.drawable.kas***_kas***,
R.drawable.killers_day_and_age,
R.drawable.garbage_bleed_like_me,
R.drawable.massive_attack_collected,
R.drawable.kas***_kas***, R.drawable.kas***_kas***,
R.drawable.kas***_kas***
;*/
public int getCount2()
for(int i=0;i<5;i++)
ImageView imageView = new ImageView(mContext);
URL url;
try
url = new URL("http://www.psdgraphics.com/file/retro-tv-icon.jpg");
Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bmp);
imageView.setId(i);
//mImageIds[i]=i;
catch (MalformedURLException e)
// TODO Auto-generated catch block
e.printStackTrace();
catch (IOException e)
// TODO Auto-generated catch block
e.printStackTrace();
return mImageIds.length;
private ImageView[] mImages;
public ImageAdapter(Context c)
mContext = c;
mImages = new ImageView[getCount2()];
public boolean createReflectedImages()
// The gap we want between the reflection and the original image
final int reflectionGap = 4;
int index = 0;
for (final int imageId : mImageIds)
// Bitmap originalImage = BitmapFactory.decodeResource(
// getResources(), imageId);
URL url;
Bitmap originalImage= null;
try
url = new URL("http://image10.bizrate-images.com/resize?sq=60&uid=2216744464");
originalImage = BitmapFactory.decodeStream(url.openConnection().getInputStream());
catch (MalformedURLException e)
// TODO Auto-generated catch block
e.printStackTrace();
catch (IOException e)
// TODO Auto-generated catch block
e.printStackTrace();
int width = originalImage.getWidth();
int height = originalImage.getHeight();
Log.v("width:",""+width+","+height);
// This will not scale but will flip on the Y axis
Matrix matrix = new Matrix();
matrix.preScale(1, -1);
Log.v("errer her", "aftr originalImage");
// Create a Bitmap with the flip matrix applied to it.
// We only want the bottom half of the image
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
height / 2, width, height / 2, matrix, false);
// Create a new bitmap with same width but taller to fit
// reflection
Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);
// Create a new Canvas with the bitmap that's big enough for
// the image plus gap plus reflection
Canvas canvas = new Canvas(bitmapWithReflection);
// Draw in the original image
canvas.drawBitmap(originalImage, 0, 0, null);
// Draw in the gap
Paint deafaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap,
deafaultPaint);
// Draw in the reflection
canvas.drawBitmap(reflectionImage, 0, height + reflectionGap,
null);
Log.v("errer her", "aftr reflectionImage");
// Create a shader that is a linear gradient that covers the
// reflection
Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0,
originalImage.getHeight(), 0,
bitmapWithReflection.getHeight() + reflectionGap,
0x70ffffff, 0x00ffffff, TileMode.CLAMP);
// Set the paint to use this shader (linear gradient)
paint.setShader(shader);
// Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
// Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width,
bitmapWithReflection.getHeight() + reflectionGap, paint);
Log.v("errer her", "aftr drawrect");
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection);
imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180));
imageView.setScaleType(ScaleType.MATRIX);
mImages[index++] = imageView;
return true;
public int getCount()
// Log.v("getCoutn(int count)", "" + mImageIds.length);
return mImageIds.length;
public Object getItem(int position)
// Log.v("getItem(int position)", "" + position);
return position;
public long getItemId(int position)
// Log.v("getItemID(int position)", "" + position);
return position;
public View getView(int position, View convertView, ViewGroup parent)
// Use this code if you want to load from resources
// ImageView i = new ImageView(mContext);
// i.setImageResource(mImageIds[position]);
// i.setLayoutParams(new CoverFlow.LayoutParams(130, 130));
// i.setScaleType(ImageView.ScaleType.MATRIX);
// return i;
// Log.v("getview int position mImages", ""+position);
ImageView imageView = new ImageView(mContext);
URL url;
try
url = new URL("http://image10.bizrate-images.com/resize?sq=60&uid=2216744464");
Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
imageView.setImageBitmap(bmp);
imageView.setId(position);
catch (MalformedURLException e)
// TODO Auto-generated catch block
e.printStackTrace();
catch (IOException e)
// TODO Auto-generated catch block
e.printStackTrace();
return imageView;
//return mImages[position];
/**
* Returns the size (0.0f to 1.0f) of the views depending on the
* 'offset' to the center.
*/
public float getScale(boolean focused, int offset)
/* Formula: 1 / (2 ^ offset) */
Log.v("getScale float ", " " + focused + " " + offset);
return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
// View v=getView(position, convertView, parent);
【问题讨论】：
【参考方案1】：1.创建ImageAdater.java
package com.sample.Adapters;
import java.util.ArrayList;
import android.app.Activity;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.ImageView;
public class ImageAdapter extends BaseAdapter
int mGalleryItemBackground;
private Activity mContext;
ArrayList<byte[]> imgarray ;
public ImageAdapter(Activity c,ArrayList<byte[]> array)
mContext = c;
this.imgarray = array ;
public int getCount()
return imgarray.size();
public Object getItem(int position)
return position;
public long getItemId(int position)
return position;
public View getView( final int position, View convertView, ViewGroup parent)
ImageView i = new ImageView(mContext);
i.setImageBitmap(BitmapFactory.decodeByteArray(imgarray.get(position), 0, imgarray.get(position).length));
i.setLayoutParams(new com.sample.custom.CoverFlow.LayoutParams(LayoutParams.WRAP_CONTENT-20, LayoutParams.WRAP_CONTENT-20));
i.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
BitmapDrawable drawable = (BitmapDrawable) i.getDrawable();
drawable.setAntiAlias(true);
return i;
public float getScale(boolean focused, int offset)
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset)));
2.图片下载方法
public static byte[] getLogoImage(String url)
try
URL imageUrl = new URL(url);
URLConnection ucon = imageUrl.openConnection();
InputStream is = ucon.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(500);
int current = 0;
while ((current = bis.read()) != -1)
baf.append((byte) current);
return baf.toByteArray();
catch (Exception e)
Log.d("ImageManager", "Error: " + e.toString());
return null;
3.声明一个ArrayList<byte[]> arraylistgallery = new ArrayList<byte[]>();
这里我假设总来的图像将是 10
for(int i=0 ; i<10 ; i++)
arraylistgallery.add(i,getLogoImage("http://www.psdgraphics.com/file/retro-tv-icon.jpg"));
在AsyncTask中下载图片并保存在arraylistgallery ArrayList
并且这样通过
coverFlow.setVisibility(View.VISIBLE);
coverFlow.setAdapter(new ImageAdapter(this,arraylistgallery));
coverFlow.setSpacing(5);
coverFlow.setSelection(arraylistgallery.size()-1, true);
coverFlow.setAnimationDuration(1000);
【讨论】：
你不应该解码getView中的图像，或者做一次然后缓存它。
有什么建议吗？但在我的项目中运行良好......请给我建议
你可能会得到一个内存不足的错误，而且它可能在一个大的项目列表上看起来很滞后
不知道该放什么...我创建了 ImageAdapter 类，还在 Coverflow_displayerActivity.java 中创建了 downloadimages 方法
谢谢@parag ..你节省了一天。【参考方案2】：
使用下面的代码。
coverFlow = new CoverFlow(this);
ImageAdapter coverImageAdapter = new ImageAdapter(this);
coverFlow.setAdapter(coverImageAdapter);
coverFlow.setSpacing(0);
coverFlow.setSelection(0, true);
coverFlow.setLayoutParams(params);
coverFlow.setOnItemClickListener(this);
coverFlow.setOnItemSelectedListener(new OnItemSelectedListener()
@Override
public void onItemSelected(CoverAdapterView<?> parent, View view, int position, long id)
// TODO Auto-generated method stub
@Override
public void onNothingSelected(CoverAdapterView<?> parent)
// TODO Auto-generated method stub
);
ImageAdapter.java
public class ImageAdapter extends BaseAdapter
public ImageLoader imageLoader;
public ImageAdapter(Context c)
Constants.ctx = c;
imageLoader = new ImageLoader(Constants.ctx.getApplicationContext());
public int getCount()
return Constants.mIsFeaturedTrueImage.size();
public Object getItem(int position)
return position;
public long getItemId(int position)
return position;
public View getView(int position, View convertView, ViewGroup parent)
System.gc();
ImageView i = new ImageView(Constants.ctx);
if (Constants.mIsFeaturedTrueImage.get(position).equals("null") || Constants.mIsFeaturedTrueImage.get(position).equals(""))
System.out.println("Hello if");
i.setImageResource(R.drawable.icon);
else
System.out.println("Hello else if");
imageLoader.DisplayImage(Constants.mIsFeaturedTrueImage.get(position), i);
i.setLayoutParams(new CoverFlow.LayoutParams(
mConstant.mImageWidth + 28, mConstant.mImageHeight + 28));
i.setScaleType(ImageView.ScaleType.MATRIX);
return i;
/**
* Returns the size (0.0f to 1.0f) of the views depending on the
* 'offset' to the center.
*/
public float getScale(boolean focused, int offset)
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
并使用 imageLoader 类从 URL 加载图像，并且 Constants.mIsFeaturedTrueImage.get(position) 是图像 URL 的数组列表。
【讨论】：
看起来他可能遇到了 OOM 异常，他需要重新采样到 bitmaps..google://resample bitmap getView【参考方案3】：我写了一个demo来实现这个问题，我结合了图库流程和通用图片加载，你可以试试，谢谢！ 你可以从这个网站下载演示： https://github.com/Jonguo/galleryflow
【讨论】：
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