最简单的SD卡文件遍历Android程序

package com.wenhao.test.sddemo;

import java.io.File;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainDemo extends Activity {
  /** Called when the activity is first created. */
  
  private Button button = null;
  private File path;
  
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
      
    button = (Button)findViewById(R.id.mybutton);
    
    //检测SD卡是否存在
    if (Environment.getExternalStorageState().equals(
        Environment.MEDIA_MOUNTED)) {
      path = Environment.getExternalStorageDirectory();
    }else{
      Toast.makeText(this, "没有SD卡", Toast.LENGTH_LONG).show();
      finish();
    }
    
    button.setOnClickListener(new OnClickListener() {
      
      @Override
      public void onClick(View v) {
        // TODO Auto-generated method stub                
        getAllFiles(path);
      }
    });
    
  }
  
  // 遍历接收一个文件路径，然后把文件子目录中的所有文件遍历并输出来 
  private void getAllFiles(File root){ 
    File files[] = root.listFiles(); 
    if(files != null){ 
      for (File f : files){ 
        if(f.isDirectory()){ 
          getAllFiles(f); 
        }else{ 
          System.out.println(f); 
        } 
      } 
    } 
  } 
   
}