从网上获取图片

  

 

效果展示

输入图片地址，点击button

布局EditText，button，ImageView

给button加监听器实现代码：

String path = imagePathText.getText().toString();
                     NetTool NTU=new NetTool();
                     String imagePath = NTU.getImagePath(getBaseContext(), path);
                     imageView.setImageBitmap(BitmapFactory.decodeFile(imagePath));

 解                  释：

•  path  图片路径
•  NetTool  从网络获取图片的工具类
•  NetTool 主要的3个方法

• public class NetTool {
        static String TAG="step";
        public static InputStream getRequest(String path) throws Exception {
              URL url = new URL(path);
              HttpURLConnection conn = (HttpURLConnection) url.openConnection();
              conn.setRequestMethod("GET");
              conn.setConnectTimeout(5000); // 5秒
              if (conn.getResponseCode() == 200) {
                    return conn.getInputStream();
              }
              return null;
  
  
        }
  
  
        public static byte[] readInputStream(InputStream inStream) throws Exception {
              ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
              byte[] buffer = new byte[4096];
              int len = 0;
              while ((len = inStream.read(buffer)) != -1) {
                    outSteam.write(buffer, 0, len);
              }
              outSteam.close();
              inStream.close();
              return outSteam.toByteArray();
        }
  
  
        // 获取网络图片，如果缓存里面有就从缓存里面获取
        public static String getImagePath(Context context, String url) {
              if (url == null)
                    return "";
              String imagePath = "";
              String fileName = "";
  
  
              // 获取url中图片的文件名与后缀
              if (url != null && url.length() != 0) {
                    fileName = url.substring(url.lastIndexOf("/") + 1);
              }
  
  
              // 图片在手机本地的存放路径,注意：fileName为空的情况
              imagePath = context.getCacheDir() + "/" + fileName;
              Log.i(TAG, "imagePath = " + imagePath);
              File file = new File(context.getCacheDir(), fileName);// 保存文件,
              if (!file.exists()) {
                    Log.i(TAG, "file 不存在 ");
                    try {
                          byte[] data = readInputStream(getRequest(url));
                          Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
                                      data.length);
  
  
                          bitmap.compress(CompressFormat.JPEG, 100, new FileOutputStream(
                                      file));
  
  
                          imagePath = file.getAbsolutePath();
                          Log.i(TAG, "imagePath : file.getAbsolutePath() = " + imagePath);
  
  
                    } catch (Exception e) {
                          Log.e(TAG, e.toString());
                    }
              }
              return imagePath;
        } 
  }