android 遍历所有文件夹和子目录搜索文件

java代码：

import java.io.File;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class ShuosouwenjianActivity extends Activity  implements OnClickListener  {

    private File file;
    private String path;
    private String info;
    private String key; //关键字
    private TextView result; // 显示结果
    private EditText et; // 编辑view
    private Button search_btn; // button view  

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        result = (TextView)findViewById(R.id.TextView_Result);
        et = (EditText)findViewById(R.id.key);
        search_btn = (Button)findViewById(R.id.button_search);
       // file = new File(Environment.getExternalStorageDirectory().getPath());
        file = new File("/sdcard/");
        info = getString(R.string.info);  

        search_btn.setOnClickListener(this);
    }  

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        path = "";
        result.setText("");
        key = et.getText().toString();
        BrowserFile(file);
    }  

    public void BrowserFile(File fileold) {
        if (key.equals("")) {
            Toast.makeText(this, getString(R.string.pleaseInput), Toast.LENGTH_LONG).show();
        } else {
         search(fileold);
            if (result.getText().equals("")) {
                Toast.makeText(this, getString(R.string.notFound), Toast.LENGTH_SHORT).show();
            }
        }
    }  

 private void search(File fileold)
    {
     try{
  File[] files=fileold.listFiles();
  if(files.length>)
  {
     for(int j=;j<files.length;j++)
     {
   if(!files[j].isDirectory())
   {
   if(files[j].getName().indexOf(key)> -)
    {
    path += "\n" + files[j].getPath();
       result.setText(info+path);

          //shuju.putString(files[j].getName().toString(),files[j].getPath().toString());
    }
   }
   else{
    this.search(files[j]);
   }
     }
  }
  }
     catch(Exception e)
     {

     }
    }
}

MAIN.XML代码：

<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/widget0"
    > 

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/button_search"
    android:layout_x="253px"
    android:layout_y="5px"
    android:text="@string/toSearch"
/>
<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/key"
    android:text="821077962.db"  

/>
<TextView
    android:layout_width="fill_parent"
    android:layout_height="370px"
    android:id="@+id/TextView_Result"
    android:layout_x="0px"
    android:layout_y="60px"
/>
</AbsoluteLayout>

strings.xml代码:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World, Activity07!</string>
    <string name="app_name">文件搜索</string>
    <string name="toSearch">搜索</string>
    <string name="info">系统SDCard目录文件路径：\n</string>
    <string name="pleaseInput">请输入关键字!</string>
    <string name="notFound">SD卡中没有相关文件!!</string>
    <string name="pathError">读取路径出错!!</string>
</resources>