异步上传文件

package com.example.asyncuploadfile;

import java.io.File;
import java.io.FileNotFoundException;

import org.apache.http.Header;

import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText et_path;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et_path = (EditText)findViewById(R.id.et_path);
    }

    public void upload(View view){
        String file_path = et_path.getText().toString().trim();
        
        AsyncHttpClient client = new AsyncHttpClient();
        String url = "http://202.96.2.149/android/upload.php";
        
        File file = new File(file_path);
        RequestParams params = new RequestParams();
        params.put("username", "zhangsan");
        params.put("password", "123456");
        try {
            params.put("myfile", file);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return;
        }
        client.post(url, params, new AsyncHttpResponseHandler(){

            @Override
            public void onSuccess(int statusCode, Header[] headers,
                    byte[] responseBody) {
                // TODO Auto-generated method stub
                String result = new String(responseBody);
                Toast.makeText(MainActivity.this, result, 0).show();
                
            }

            @Override
            public void onFailure(int statusCode, Header[] headers,
                    byte[] responseBody, Throwable error) {
                // TODO Auto-generated method stub
                Toast.makeText(MainActivity.this, "请求失败!", 0).show();
                
            }
            
        });
    }

}