从网址保存图像

Question

我想用一个按钮在我的代码中的URL保存图像我已经创建目标文件夹，但我已经尝试过各种代码来保存图片，但不工作：

public class B_X extends Activity { 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.bx); 

     Button buttonSetWallpaper = (Button)findViewById(R.id.bSetWall); 
     buttonSetWallpaper.setOnClickListener(new Button.OnClickListener(){ 

      @Override 
      public void onClick(View arg0) { 
       // TODO Auto-generated method stub 
       File folder = new File(Environment.getExternalStorageDirectory() + "/PerfectAss/"); 
       boolean success = false; 
       if (!folder.exists()) { 
        success = folder.mkdirs(); 
       } 

       if (!success) { 
      } else { 
      } 

       Toast.makeText(getApplicationContext(), "The image has been saved", Toast.LENGTH_LONG).show(); 
        URL url = new URL ("http://bitsparrow.altervista.org/wp-content/uploads/2013/04/5.jpg"); 
        InputStream input = url.openStream(); 
        try { 

         File storagePath = Environment.getExternalStorageDirectory(); 
         OutputStream output = new FileOutputStream (storagePath + "/myImage.png"); 
         try { 
          byte[] buffer = new byte[1500]; 
          int bytesRead = 0; 
          while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) { 
          output.write(buffer, 0, bytesRead); 
          } 
          } finally { 
           output.close(); 
           } 
           } finally { 
           input.close(); 
           } 

请帮我解决这段代码。

Answer 1

使用这样的简单：它保存文件在"sdcard/dhaval_files/"。只需替换您的文件夹名称并在Android清单文件中授予write_external_storage权限。

public void file_download(String uRl) { 
     File direct = new File(Environment.getExternalStorageDirectory() 
       + "/dhaval_files"); 

     if (!direct.exists()) { 
      direct.mkdirs(); 
     } 

     DownloadManager mgr = (DownloadManager) this.getSystemService(Context.DOWNLOAD_SERVICE); 

     Uri downloadUri = Uri.parse(uRl); 
     DownloadManager.Request request = new DownloadManager.Request(
       downloadUri); 

     request.setAllowedNetworkTypes(
       DownloadManager.Request.NETWORK_WIFI 
         | DownloadManager.Request.NETWORK_MOBILE) 
       .setAllowedOverRoaming(false).setTitle("Demo") 
       .setDescription("Something useful. No, really.") 
       .setDestinationInExternalPublicDir("/dhaval_files", "test.jpg"); 

     mgr.enqueue(request); 

    } 

Answer 2

有你有权限进入你的清单文件

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 

并尝试这个代码

或者那就试试这个代码，它会工作

URL url = new URL ("file://some/path/anImage.png"); 
InputStream input = url.openStream(); 

try { 
    //The sdcard directory e.g. '/sdcard' can be used directly, or 
    //more safely abstracted with getExternalStorageDirectory() 
    File storagePath = Environment.getExternalStorageDirectory(); 
    OutputStream output = new FileOutputStream (storagePath + "/myImage.png"); 

    try { 
     byte[] buffer = new byte[aReasonableSize]; 
     int bytesRead = 0; 

     while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) { 
      output.write(buffer, 0, bytesRead); 
     } 
    } finally { output.close(); } 
} finally { input.close(); }