GridView顯示網絡圖片

 

   今天在GridView中顯示網絡圖片,忙活了半天.才搞定.其中最大的原因就是,不明白連接百度的ＵＲＬ不能下載圖片，我一直以爲我的代碼有問題，後來重新到別的網站上找個連接地址，即解決了此問題．對於這個百度，我無語了（＾ｏ＾）．

 

這個是ActivityMain.java的代碼:

import java.io.IOException; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.GridView; import android.widget.ImageView; public class ActivityMain extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); setTitle("用圖片填充GridView"); GridView gridview = (GridView) findViewById(R.id.grid_view); gridview.setAdapter(new ImageAdapter(this)); } public class ImageAdapter extends BaseAdapter { private Context mContext; public ImageAdapter(Context c) { mContext = c; } public int getCount() { return myImageURL.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } /** * 即使在網速不好的時候也能加載圖片. * 擴展:因爲聯網比較慢,爲了用戶的友好,可以使用線程Handle,進度條 * @param c * @param url * @return */ public synchronized Bitmap getBitMap(Context c, String url) { URL myFileUrl = null; Bitmap bitmap = null; try { myFileUrl = new URL(url); } catch (MalformedURLException e) { bitmap = BitmapFactory.decodeResource(c.getResources(), R.drawable.defaultimage); //當網絡連接異常後,給個默認圖片 return bitmap; } try { //打開網絡連接 HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection(); conn.setDoInput(true); conn.connect(); InputStream is = conn.getInputStream(); //把得到的內容轉換成流 int length = (int) conn.getContentLength(); //獲取文件的長度 if (length != -1) { byte[] imgData = new byte[length]; byte[] temp = new byte[512]; int readLen = 0; int destPos = 0; while ((readLen = is.read(temp)) > 0) { System.arraycopy(temp, 0, imgData, destPos, readLen); destPos += readLen; } bitmap = BitmapFactory.decodeByteArray(imgData, 0, imgData.length); } } catch (IOException e) { bitmap = BitmapFactory.decodeResource(c.getResources(), R.drawable.defaultimage); return bitmap; } return bitmap; } public View getView(int position, View convertView, ViewGroup parent) { /* ImageView */ ImageView imageView = new ImageView(this.mContext); try { //在網絡條件好的情況下使用已註釋的方法 /*URL aryURI = new URL(myImageURL[position]); 打開連接 URLConnection conn = aryURI.openConnection(); conn.connect(); 轉變爲 InputStream InputStream is = conn.getInputStream(); 將InputStream轉變爲Bitmap */ Bitmap bm = getBitMap(mContext, myImageURL[position]); if (bm == null) { bm=BitmapFactory.decodeResource(mContext.getResources(), R.drawable.defaultimage); Log.i("BitmapPicture", "picture is null!!"); } /* 關閉InputStream */ //is.close(); /* 添加圖片 */ imageView.setImageBitmap(bm); } catch (Exception e) { e.printStackTrace(); } // 填充ImageView imageView.setLayoutParams(new GridView.LayoutParams(150, 133)); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); imageView.setPadding(4, 2, 2, 2); return imageView; } // references to our images //地址自己去選擇,可以嘗試多個網站的,我試過百度的圖片,不知爲啥不可以? private String[] myImageURL = { "http://pic3.nipic.com/20090520/2595280_225552071_2.jpg", "http://pic9.nipic.com/20100831/4164977_115736793120_2.jpg", "http://pic9.nipic.com/20100831/4164977_115736793120_3.jpg", "http://pic9.nipic.com/20100831/4164977_115736793120_4.jpg", "http://pic9.nipic.com/20100831/4164977_115736793120_5.jpg", "http://pic9.nipic.com/20100831/4164977_115736793120_6.jpg" }; } }

 

 

這裏是main.xml 的代碼(可能有抄襲的嫌疑,不是我首創): 

 

 

 <?xml version="1.0" encoding="utf-8"?> <AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <GridView android:id="@+id/grid_view" android:layout_width="fill_parent" android:layout_height="wrap_content" android:numColumns="3" android:verticalSpacing="5dp" android:horizontalSpacing="5dp" android:columnWidth="20dp" android:stretchMode="columnWidth" android:gravity="center" /> </AbsoluteLayout>

 

 

GridView裏的內容不再解釋,相信會android的coby看懂.

 

好了, 到這裏也許就要結束了.哦,忘了一句很重要的代碼.在android要求聯網的時候,必須在AndroidManifest.xml這個配置文件裏

加上這麼一句: <uses-permission android:name="android.permission.INTERNET" />

它必須和application節點同級.

 

好了,現在就來看看效果吧!

 

嘻嘻..... 效果不咋地.前兩張是網站地址正確.後面的是網址無效.給的默認圖片.