2014-07-29 13:39:09
MainActivity.java

package com.example.sample_4_21;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.Window;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ListActivity {
    List<String> filelist = null;
    String rootPath = "/";
    String currentpath;
    String parentPath;
    ArrayAdapter<String> adapter;
    ArrayAdapter<String> maAdapter;
    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.mPath);
        init(rootPath);
    }

    void init(String path) {
        adapter = new ArrayAdapter<String>(this, R.layout.file_row,
                getFileList(path));
        setListAdapter(adapter);
        tv.setText(path);
        currentpath = path;
    }

    List<String> getFileList(String path) {
        File f = new File(path);
        File[] allfile = f.listFiles();
        filelist = new ArrayList<String>();
        parentPath = f.getParent();
        if (parentPath==null) {//如果为根目录，则f.getparent()为null
            parentPath = "/";
        }
        filelist.add("back to..." +parentPath);
        for (File file : allfile) {
            filelist.add(file.getPath());
        }
        return filelist;
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        // TODO Auto-generated method stub
        super.onListItemClick(l, v, position, id);
        if (position == 0) {
            if (currentpath == rootPath) {
                Toast.makeText(this, "为根目录", Toast.LENGTH_SHORT).show();
            } else {
                init(parentPath);
            }
        } else {
            if (new File(filelist.get(position)).isFile()) {
                Toast.makeText(this, "文件", Toast.LENGTH_SHORT).show();
            } else if (!new File(filelist.get(position)).canRead()) {
                Toast.makeText(this, "不可读", Toast.LENGTH_SHORT).show();
            } else {
                init(filelist.get(position));
            }
        }

    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        if(keyCode==KeyEvent.KEYCODE_BACK&&event.getAction()==KeyEvent.ACTION_UP){
            if(currentpath==rootPath){
                new AlertDialog.Builder(this)
                .setTitle("提示")
                .setMessage("确定退出吗")
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        MainActivity.this.finish();
                    }
                })
                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                    }
                })
                .show();
                return true;
            }else{
                init(parentPath);
                return false;
            }    
        }else{
            return false;
        }
    }
}