学步园

1.已知图片网址，获得图像资源：

public Bitmap getBmp(URL imgUrl){<br /> URL url=new URL(imgUrl);<br /> URLConnection conn=url.openConnection();<br /> conn.connect();<br /> Bitmap bm=BitmapFactory.decodeStream(conn.getInputStream());<br /> return bm;<br /> }

android 图片编辑时需要从外界（sdcard ,res/.png...,xml）读取图片到画布，其中从sdcard读取图片到画布的过程如下： 
public void drawBitMapFromSDcard(String dir) {<br /> if(dir ==null || dir.equals("")){<br /> return ;<br /> }<br /> bitMap = BitmapFactory.decodeFile(dir);<br /> int width = bitMap.getWidth();<br /> int height = bitMap.getHeight();
如果图片像素太大超过手机屏幕大小可以按照手机屏比例进行缩放 

if (width > 320 && height > 480) {<br /> int newWidth = 320;<br /> int newHeight = 480;<br /> float scaleWidth = ((float) newWidth) / width;<br /> float scaleHeight = ((float) newHeight) / height;<br /> float minScale = Math.min(scaleWidth, scaleHeight);<br /> matrix = new Matrix();<br /> matrix.postScale(minScale, minScale);<br /> bitMap = Bitmap.createBitmap(bitMap, 0, 0, width, height,<br /> matrix, true);<br /> }
显示图片到手机屏幕 
mCanvas.drawBitmap(bitMap, 0, 0, mPaint);<br /> invalidate();<br />

（二）图片剪切 
在android 画布上对图像进行剪切时，首先选中一块区域，得到所选区域的像素点，然后放到到要粘贴的位置。剪切代码如下 
public int[] getClipRectangePix(RectF rectf, Bitmap bitmap) {<br /> int width = (int) rectf.width();<br /> int height = (int) rectf.height();<br /> int[] clipRectangePix = new int[(width * height)];// ????<br /> int x = (int) rectf.left;<br /> int y = (int) rectf.top;<br /> bitmap.getPixels(clipRectangePix, 0, width, x, y, width, height);<br /> // Log.v("pix Color:",""+ clipRectangePix[0] );<br /> return clipRectangePix;<br /> }

2.播放网络音乐

a.通过MediaPlayer的setDataSource()对MP3文件进行“缓冲流”的播放，此方法没有对音乐文件进行保存，适用于在线试听，具体使用方法是：

MediaPlayer mp=new MediaPlayer();<br /> try{<br /> mp.setDataSource(XXX.this,Uri.parse("musicURL"));<br /> mp.prepare();<br /> mp.start();<br /> }catch(Exception e){<br /> } 

b.将在线音乐下载下来才能试听，具体方法：

MediaPlayer mp=new MediaPlayer();<br /> final Runnable r = new Runnable() {<br /> public void run() {<br /> try {<br /> setDataSource("http://XXX/XXX/XXX.mp3");<br /> mp.prepare();<br /> mp.start();<br /> } catch (Exception e) {<br /> }<br /> }<br /> };<br /> new Thread(r).start();<br /> /**<br /> *musicurl为音乐网址或者是本地绝对地址<br /> **/<br /> public void setDataSource(String musicurl) throws Exception {<br /> if (!URLUtil.isNetworkUrl(musicurl)) {<br /> mp.setDataSource(musicurl);<br /> } else {<br /> try {<br /> URL url = new URL(musicurl);<br /> URLConnection conn = url.openConnection();<br /> conn.connect();<br /> InputStream is = conn.getInputStream();<br /> if(is==null){<br /> throw new RuntimeException("stream is null");<br /> }<br /> String extentions=musicurl.substring(musicurl.lastIndexOf(".")+1);//取扩展名<br /> if(extentions==""){<br /> extentions="dat";<br /> }<br /> File mp3file = File.createTempFile("yk3372", "."+extentions);<br /> String path = mp3file.getAbsolutePath();//存放本地的具体地址<br /> FileOutputStream fos = new FileOutputStream(path);<br /> byte buf[] = new byte[128];<br /> do {<br /> int numread = is.read(buf);<br /> if (numread <= 0) {<br /> break;<br /> }<br /> fos.write(buf, 0, numread);<br /> } while (true);<br /> mp.setDataSource(path);<br /> try {<br /> is.close();<br /> } catch (Exception e) {<br /> }<br /> } catch (Exception e) {<br /> // TODO Auto-generated catch block<br /> e.printStackTrace();<br /> }