一段c语言编写的代码

代码说明：

package com.example.net_ftp;   import java.io.IOException;   //import com.example.net_ftp.ContinueFTP.DownloadStatus;   import android.os.Bundle; import android.os.Environment; import android.os.Handler; import android.os.Looper; import android.os.Message; import android.app.Activity; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.TextView;   public class MainActivity extends Activity {           private Button connectbut  = null;     private Button uploadbut = null;     private Button downloadbut = null;     private Button disconnectbut = null;     private TextView connecttext = null;     private TextView uploadtext =