android 文件下载到SDCARD

操作SDcard 需要权限

//写入数据权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
//创建和删除文件权限
 <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> 

 主界面

package com.example.loaddown;

import java.io.File;

import util.DownUtil;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;

public class Activity08 extends Activity {
	
	EditText t1 ;
	EditText t2 ;
	Spinner sp ;
	Button b1 ;
	String name = null ;
	ArrayAdapter ad = null ;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity08);
        
        t1 = (EditText) findViewById(R.id.t1);
        t2 = (EditText) findViewById(R.id.t2);
        
        b1 = (Button) findViewById(R.id.b1);
        b1.setText("下载");
        
        sp = (Spinner) findViewById(R.id.spin);
        ad = ArrayAdapter.createFromResource(this, R.array.spin, android.R.layout.simple_spinner_item);
        ad.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        sp.setPrompt("文件格式");
        sp.setAdapter(ad);
        sp.setOnItemSelectedListener(new OnItemSelectedListener() {

			@Override
			public void onItemSelected(AdapterView<?> arg0, View arg1,
					int arg2, long arg3) {
				name = ad.getItem(arg2).toString();
				System.out.println(name);
			}

			@Override
			public void onNothingSelected(AdapterView<?> arg0) {
			}
		}) ;
        
        
        b1.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				
			String loadpath = t1.getText().toString();
			String fileName = t2.getText().toString();
			DownUtil down = new DownUtil();
			File file = new File(Environment.getExternalStorageDirectory()+"/"+fileName+name);
			Intent intent = new Intent() ;
			if(file.exists()){
				intent.putExtra("message", "文件已经存在");
			}
			else{
			down.loadTxt(fileName+name, loadpath);
			intent.putExtra("message", "下载完成");
			}
			
			intent.setClass(Activity08.this, OverActivity.class);
			Activity08.this.startActivity(intent);
			
			}
		});
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_activity08, menu);
        return true;
    }
}

 

结果界面：

package com.example.loaddown;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;


public class OverActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.over);
		TextView text = (TextView) findViewById(R.id.text1);
		Intent intent = getIntent();
		String msg = intent.getStringExtra("message");
		text.setText(msg);
		
	}

	
	
}

  

 

工具类：

package util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.os.Environment;

public class DownUtil {
	private URL url = null ;
	private HttpURLConnection con = null ; 
	String filePath ;

	
	public File down(String fileName,String loadPath){
		
			filePath = Environment.getExternalStorageDirectory()+"/";
			System.out.println(filePath);
			File file = new File(filePath+fileName);
		try {
			url = new URL(loadPath);
			con = (HttpURLConnection) url.openConnection() ;
			InputStream in = con.getInputStream() ;
			BufferedInputStream bfin = new BufferedInputStream(in);
			BufferedOutputStream bfout = new BufferedOutputStream(new FileOutputStream(file));
			int k = 0;
			byte b[] = new byte[4*1024];
			while((k=bfin.read(b))!=-1){
				bfout.write(b);
			}
			
			bfout.flush();
			bfout.close();
			
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return file;
		
	}
	
	
	public File loadTxt(String fileName,String loadPath){
		
		filePath = Environment.getExternalStorageDirectory()+"/";
		System.out.println(filePath);
		File file = new File(filePath+fileName);
		try {
			url = new URL(loadPath);
			con = (HttpURLConnection) url.openConnection() ;
			InputStream in = con.getInputStream() ;
			
			BufferedReader reader = new BufferedReader(new InputStreamReader(in));
			BufferedWriter writer = new BufferedWriter(new FileWriter(file));
			String s = null ;
			while ((s= reader.readLine())!=null){
				writer.write(s);
			}			
			writer.flush();
			writer.close();
			
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return file;

	}
	
	
}