Android之SD卡文件浏览器

介绍：SD卡文件浏览器主要实现了对文件通过listview进行展示，功能比较简单，代码也有相应的注释，就不多说了

XML布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <!-- 显示当前路径的文本 -->

    <TextView
        android:id="@+id/path"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:gravity="center_horizontal"
        android:text="123" />
    <!-- 当前路径下文件列表的listview -->

    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/path"
        android:divider="#000"
        android:dividerHeight="1px" >
    </ListView>
    <!-- 返回上一级目录的button -->

    <Button
        android:id="@+id/parent"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:background="@drawable/buttonbg"
        android:text="返回上一级" >
    </Button>

</RelativeLayout>

Java代码

package com.example;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
	private TextView path;
	private ListView listView;
	private Button back;
	File currentParent; // 记录当前的父文件夹
	File[] currentFiles; // 记录当前路径下所有文件夹的文件数组

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		this.requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题栏

		this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//去掉信息栏
		
		setContentView(R.layout.activity_main);
		path = (TextView) findViewById(R.id.path);
		listView = (ListView) findViewById(R.id.list);
		// 获取系统的sd卡目录
		File root = new File("/mnt/sdcard");

		File dir = Environment.getExternalStorageDirectory();
		final String r = dir.getAbsolutePath(); // 根目录路径

		// 如果sd卡存在
		if (root.exists()) {
			currentParent = root;
			currentFiles = root.listFiles();
			// 使用当前目录下的全部文件、文件夹来填充listview
			inflateListView(currentFiles);
		}

		// 为listview的列表项的单击事件绑定监听器
		listView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> parent, View view,
					int position, long id) {
				// 用户点击了文件，立即返回，不做任何处理
				if (currentFiles[position].isFile()) {
					return;
				}
				// 获取用户点击的文件夹下的所有文件
				File[] tmp = currentFiles[position].listFiles();
				if (tmp == null || tmp.length == 0) {
					Toast.makeText(getApplicationContext(),
							"当前路径不可访问or该路径下没有文件", 5).show();

				} else {
					// 获取用户点击的列表项对应的文件夹，设为当前的父文件夹
					currentParent = currentFiles[position];
					// 保存当前父文件夹内的全部文件和文件夹
					currentFiles = tmp;
					// 再次更新listview
					inflateListView(currentFiles);
				}

			}
		});

		// 获取上一级目录的button
		back = (Button) findViewById(R.id.parent);
		back.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {
				try {

					if (!currentParent.getCanonicalPath().equals("/mnt/sdcard")) {
						// 获取上一级目录
						if (currentParent.getCanonicalPath().equals(r)) {
							Toast.makeText(getApplicationContext(), "已经是根目录", 5)
									.show();
						} else {
							currentParent = currentParent.getParentFile();
							// 列出当前目录下所有文件
							currentFiles = currentParent.listFiles();
							// 再次更新ListView
							inflateListView(currentFiles);
						}

					}

				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		});

	}

	protected void inflateListView(File[] files) {
		// 创建一个list集合，list集合的元素是Map
		List<Map<String, Object>> listItems = new ArrayList<Map<String, Object>>();
		for (int i = 0; i < files.length; i++) {
			Map<String, Object> listItem = new HashMap<String, Object>();
			// 如果当前的file是文件夹，使用folder图标，否则使用file图标
			if (files[i].isDirectory()) {
				listItem.put("icon", R.drawable.folder);
			} else {
				listItem.put("icon", R.drawable.file);
			}
			listItem.put("filename", files[i].getName());
			// 添加list项
			listItems.add(listItem);
		}

		// 创建一个SimpleAdapter
		SimpleAdapter simpleAdapter = new SimpleAdapter(this, listItems,
				R.layout.line, new String[] { "icon", "filename" }, new int[] {
						R.id.icon, R.id.file_name });
		// 为listview设置adapter
		listView.setAdapter(simpleAdapter);
		try {
			path.setText("当前路径为：" + currentParent.getCanonicalPath());
		} catch (Exception e) {
			e.printStackTrace();
		}

	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// // Inflate the menu; this adds items to the action bar if it is
		// present.
		 getMenuInflater().inflate(R.menu.main, menu);
		 return true;
		
	}

	
	// 再按一次退出
	long waitTime = 2000;
	long touchTime = 0;

	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if (event.getAction() == KeyEvent.ACTION_DOWN
				&& KeyEvent.KEYCODE_BACK == keyCode) {
			long currentTime = System.currentTimeMillis();
			if ((currentTime - touchTime) >= waitTime) {
				Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();
				touchTime = currentTime;
			} else {
				finish();
			}
			return true;
		}
		return super.onKeyDown(keyCode, event);
	}

}

效果图