最简单的Android 遍历SD卡的方法

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);  
                }  
            }  
        }  
    }  
      
}