尝试使用以下代码将 zip 下载到 sd 卡，我得到 NullpointerException。当尝试一些审讯时，我知道实际上没有下载 zip 文件。那么，请您帮忙看看代码是否需要一些更改或 zip 有什么问题？M 只停留在这一点上。请帮助...我的代码如下...
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String from = "http://192.168.1.63/ZipFile/Text.zip" ;
String to = Environment.getExternalStorageDirectory() + "/newunzip/";
try {
((TextView) findViewById(R.id.display)).append("\n in try after function :");
downloadFile(from, to);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
((TextView) findViewById(R.id.display)).append("\n \n Exception occured :");
((TextView) findViewById(R.id.display)).append("\n \n Exception message is :"+e.getMessage());
((TextView) findViewById(R.id.display)).append("\n \n Exception is :"+e.toString());
}
}
private void downloadFile(String from, String to) throws Exception
{
((TextView) findViewById(R.id.display)).append("\n \n in function call :");
HttpURLConnection conn = (HttpURLConnection)new URL(from).openConnection();
conn.setDoInput(true);
conn.setConnectTimeout(100000); // timeout 100 secs
conn.connect();
((TextView) findViewById(R.id.display)).append("\n \n Connecting to url :"+ conn);
InputStream input = conn.getInputStream();
byte[] b = null;
input.read(b);
((TextView) findViewById(R.id.display)).append("\n \n input method :"+ b);
FileOutputStream fOut = new FileOutputStream(to);
byte[] b1 = null;
input.read(b1);
((TextView) findViewById(R.id.display)).append("\n \n output method :"+ b1);
int byteCount = 0;
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = input.read(buffer)) != -1)
{
((TextView) findViewById(R.id.display)).append("\n \n reading/writing files :");
fOut.write(buffer, 0, bytesRead);
byteCount += bytesRead;
}
fOut.flush();
((TextView) findViewById(R.id.display)).append("\n \n flush & close :");
fOut.close();
}
}