需要加入开源组件的jar包

package com.itheima.download2;import java.io.File;import android.app.Activity;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.EditText;import android.widget.TextView;import android.widget.Toast;import com.lidroid.xutils.HttpUtils;import com.lidroid.xutils.exception.HttpException;import com.lidroid.xutils.http.HttpHandler;import com.lidroid.xutils.http.ResponseInfo;import com.lidroid.xutils.http.callback.RequestCallBack;public class MainActivity extends Activity {	private EditText et_path;	private TextView tv_info;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		et_path = (EditText) findViewById(R.id.et_path);		tv_info = (TextView) findViewById(R.id.tv_info);	}	public void download(View view){		String path = et_path.getText().toString().trim();		if(TextUtils.isEmpty(path)){			Toast.makeText(this, "请输入下载的路径", 0).show();			return;		}else{			HttpUtils http = new HttpUtils();			HttpHandler handler = http.download(path,					"/sdcard/xxx.zip",				    true, // 如果目标文件存在，接着未完成的部分继续下载。服务器不支持RANGE时将从新下载。				    true, // 如果从请求返回信息中获取到文件名，下载完成后自动重命名。				    new RequestCallBack
    
     () {				        @Override				        public void onStart() {				        	tv_info.setText("conn...");				        }				        @Override				        public void onLoading(long total, long current, boolean isUploading) {				        	tv_info.setText(current + "/" + total);				        }				        @Override				        public void onSuccess(ResponseInfo
     
       responseInfo) {				        	tv_info.setText("downloaded:" + responseInfo.result.getPath());				        }				        @Override				        public void onFailure(HttpException error, String msg) {				        	tv_info.setText(msg);				        }				});		}	}}