Android下載文件

package com.test;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.webkit.URLUtil;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Main extends Activity {
 
    private TextView mTextView01;
    private EditText mEditText01;
    private Button mButton01;
    private static final String TAG = "DOWNLOADAPK";
    private String currentFilePath = "";
    private String currentTempFilePath = "";
    private String strURL="";
    private String fileEx="";
    private String fileNa="";
   
    public void onCreate(Bundle savedInstanceState)
    {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      
      mTextView01 = (TextView)findViewById(R.id.myTextView1);
      mButton01 = (Button)findViewById(R.id.myButton1);
      mEditText01 =(EditText)findViewById(R.id.myEditText1);
  
      mButton01.setOnClickListener(new Button.OnClickListener()
      {
        public void onClick(View v)
        {
          /* 文件會下載至local端 */
          mTextView01.setText("下載中...");
          strURL = mEditText01.getText().toString();
          /*取得欲安裝程序之文件名稱*/
          fileEx = strURL.substring(strURL.lastIndexOf(".")
          +1,strURL.length()).toLowerCase();
          fileNa = strURL.substring(strURL.lastIndexOf("/")
          +1,strURL.lastIndexOf("."));
          getFile(strURL);
         }
       }
      );
     
      mEditText01.setOnClickListener(new EditText.OnClickListener()
      {

        public void onClick(View arg0){
          mEditText01.setText("");
          mTextView01.setText("遠程安裝程序(請輸入URL)");
        }
      });
    }
   
    /* 處理下載URL文件自定義函數 */
    private void getFile(final String strPath)  {
      try
      {
        if (strPath.equals(currentFilePath) )
        {
          getDataSource(strPath);
        }
        currentFilePath = strPath;
        Runnable r = new Runnable()
        {
          public void run()
          {
            try
            {
              getDataSource(strPath);
            }
            catch (Exception e)
            {
              Log.e(TAG, e.getMessage(), e);
            }
          }
        };
        new Thread(r).start();
      }
      catch(Exception e)
      {
        e.printStackTrace();
      }
    }
   
     /*取得遠程文件*/
    private void getDataSource(String strPath) throws Exception
    {
      if (!URLUtil.isNetworkUrl(strPath))
      {
        mTextView01.setText("錯誤的URL");
      }
      else
      {
        /*取得URL*/
        URL myURL = new URL(strPath);
        /*建立鏈接*/
        URLConnection conn = myURL.openConnection();
        conn.connect();
        /*InputStream 下載文件*/
        InputStream is = conn.getInputStream();
        if (is == null)
        {
          throw new RuntimeException("stream is null");
        }
        /*建立臨時文件*/
        File myTempFile = File.createTempFile(fileNa, "."+fileEx);
        /*取得站存盤案路徑*/
        currentTempFilePath = myTempFile.getAbsolutePath();
        /*將文件寫入暫存盤*/
        FileOutputStream fos = new FileOutputStream(myTempFile);
        byte buf[] = new byte[128];
        do
        {
          int numread = is.read(buf);
          if (numread <= 0)
          {
            break;
          }
          fos.write(buf, 0, numread);
        }while (true);
       
        /*打開文件進行安裝*/
        openFile(myTempFile);
        try
        {
          is.close();
        }
        catch (Exception ex)
        {
          Log.e(TAG, "error: " + ex.getMessage(), ex);
        }
      }
    }
    
    /* 在手機上打開文件的method */
    private void openFile(File f)
    {
      Intent intent = new Intent();
      intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
      intent.setAction(android.content.Intent.ACTION_VIEW);
     
      /* 調用getMIMEType()來取得MimeType */
      String type = getMIMEType(f);
      /* 設置intent的file與MimeType */
      intent.setDataAndType(Uri.fromFile(f),type);
      startActivity(intent);
    }

    /* 判斷文件MimeType的method */
    private String getMIMEType(File f)
    {
      String type="";
      String fName=f.getName();
      /* 取得擴展名 */
      String end=fName.substring(fName.lastIndexOf(".")
      +1,fName.length()).toLowerCase();
     
      /* 依擴展名的類型決定MimeType */
      if(end.equals("m4a")||end.equals("mp3")||end.equals("mid")||
      end.equals("xmf")||end.equals("ogg")||end.equals("wav"))
      {
        type = "audio";
      }
      else if(end.equals("3gp")||end.equals("mp4"))
      {
        type = "video";
      }
      else if(end.equals("jpg")||end.equals("gif")||end.equals("png")||
      end.equals("jpeg")||end.equals("bmp"))
      {
        type = "image";
      }
      else if(end.equals("apk"))
      {
        /* android.permission.INSTALL_PACKAGES */
        type = "application/vnd.android.package-archive";
      }
      else
      {
        type="*";
      }
      /*若是沒法直接打開，就跳出軟件列表給用戶選擇 */
      if(end.equals("apk"))
      {
      }
      else
      {
        type += "/*"; 
      }
      return type; 
    }

    /*自定義刪除文件方法*/
    private void delFile(String strFileName)
    {
      File myFile = new File(strFileName);
      if(myFile.exists())
      {
        myFile.delete();
      }
    }
   
    /*當Activity處於onPause狀態時,更改TextView文字狀態*/
    protected void onPause()
    {
      mTextView01 = (TextView)findViewById(R.id.myTextView1);
      mTextView01.setText("下載成功");
      super.onPause();
    }

    /*當Activity處於onResume狀態時,刪除臨時文件*/
    protected void onResume()
    { 
      /* 刪除臨時文件 */
      delFile(currentTempFilePath);
      super.onResume();
    }
}