文件选择器
今天给大家分享下文件选择器的作用 ， 具体就是获取用户在在SD卡选中的文件/文件夹路径 ，类似于C#中OpenFileDialog控件(对C#的一站式开发还是念念不忘)。功能实现起来比较简单，主要是帮助大家节省开发时间。
网上流传较广的一个成品如下 <[Android实例] 文件选择器>， 本文也是根据上面的成品修改而成，使其更易理解，效率更高。 除此之外，主要特色有：
1、我们监听了用户按下Back键的事件，使其返回上一层目录；
2、针对不同的文件类型(文件vs文件夹 ， 目标文件vs其他文件)做了特殊处理。
知识点一、 File 类的使用
文件选择器的主要功能是：浏览文件\文件夹、文件类型等；都是通过Java File类来实现的。
知识点二、调用方法说明
使用了startActivityForResult()发起调用以及onActivityResult()方法接受回调后的信息。
截图如下：
其他的也没什么好说了，大家看看代码注释吧~~ so easy - - 。
FileChooserActivity.java 实现文件选择的类 。
public class CopyOfFileChooserActivity extends Activity {
private String mSdcardRootPath ; //sdcard 根路径
private String mLastFilePath ; //当前显示的路径
private ArrayList mFileLists ;
private FileChooserAdapter mAdatper ;
//配置适配器
private void setGridViewAdapter(String filePath) {
updateFileItems(filePath);
mAdatper = new FileChooserAdapter(this , mFileLists);
mGridView.setAdapter(mAdatper);
}
//根据路径更新数据，并且通知Adatper数据改变
private void updateFileItems(String filePath) {
mLastFilePath = filePath ;
mTvPath.setText(mLastFilePath);
if(mFileLists == null)
mFileLists = new ArrayList() ;
if(!mFileLists.isEmpty())
mFileLists.clear() ;
File[] files = folderScan(filePath);
if(files == null)
return ;
for (int i = 0; i < files.length; i++) {
if(files[i].isHidden()) // 不显示隐藏文件
continue ;
String fileAbsolutePath = files[i].getAbsolutePath() ;
String fileName = files[i].getName();
boolean isDirectory = false ;
if (files[i].isDirectory()){
isDirectory = true ;
}
FileInfo fileInfo = new FileInfo(fileAbsolutePath , fileName , isDirectory) ;
//添加至列表
mFileLists.add(fileInfo);
}
//When first enter , the object of mAdatper don't initialized
if(mAdatper != null)
mAdatper.notifyDataSetChanged(); //重新刷新
}
//获得当前路径的所有文件
private File[] folderScan(String path) {
File file = new File(path);
File[] files = file.listFiles();
return files;
}
private AdapterView.OnItemClickListener mItemClickListener = new OnItemClickListener() {
public void onItemClick(AdapterView adapterView, View view, int position,
long id) {
FileInfo fileInfo = (FileInfo)(((FileChooserAdapter)adapterView.getAdapter()).getItem(position));
if(fileInfo.isDirectory()) //点击项为文件夹, 显示该文件夹下所有文件
updateFileItems(fileInfo.getFilePath()) ;
else if(fileInfo.isPPTFile()){ //是ppt文件 ， 则将该路径通知给调用者
Intent intent = new Intent();
intent.putExtra(EXTRA_FILE_CHOOSER, fileInfo.getFilePath());
setResult(RESULT_OK , intent);
finish();
}
else { //其他文件.....
toast(getText(R.string.open_file_error_format));
}
}
};
public boolean onKeyDown(int keyCode , KeyEvent event){
if(event.getAction() == KeyEvent.ACTION_DOWN && event.getKeyCode()
== KeyEvent.KEYCODE_BACK){
backProcess();
return true ;
}
return super.onKeyDown(keyCode, event);
}
//返回上一层目录的操作
public void backProcess(){
//判断当前路径是不是sdcard路径 ， 如果不是，则返回到上一层。
if (!mLastFilePath.equals(mSdcardRootPath)) {
File thisFile = new File(mLastFilePath);
String parentFilePath = thisFile.getParent();
updateFileItems(parentFilePath);
}
else { //是sdcard路径 ，直接结束
setResult(RESULT_CANCELED);
finish();
}
}
}
界面依旧很丑陋，�� ，大家可以根据需要在此基础上添加功能，下面选择目录也基本上同理。
目录选择器
chooserdialog.xml
package hkp.dirchooser;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.view.Gravity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class DirChooserDialog extends Dialog implements android.view.View.OnClickListener{
private ListView list;
ArrayAdapter Adapter;
ArrayList arr=new ArrayList();
Context context;
private String path;
private TextView title;
private EditText et;
private Button home,back,ok;
private LinearLayout titleView;
private int type = 1;
private String[] fileType = null;
public final static int TypeOpen = 1;
public final static int TypeSave = 2;
/**
* @param context
* @param type 值为1表示创建打开目录类型的对话框，2为创建保存文件到目录类型的对话框
* @param fileType 要过滤的文件类型,null表示只选择目录
* @param resultPath 点OK按钮返回的结果，目录或者目录+文件名
*/
public DirChooserDialog(Context context,int type,String[]fileType,String resultPath) {
super(context);
// TODO Auto-generated constructor stub
this.context = context;
this.type = type;
this.fileType = fileType;
this.path = resultPath;
}
/* (non-Javadoc)
* @see android.app.Dialog#dismiss()
*/
@Override
public void dismiss() {
// TODO Auto-generated method stub
super.dismiss();
}
/* (non-Javadoc)
* @see android.app.Dialog#onCreate(android.os.Bundle)
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.chooserdialog);
path = getRootDir();
arr = (ArrayList) getDirs(path);
Adapter = new ArrayAdapter(context,android.R.layout.simple_list_item_1, arr);
list = (ListView)findViewById(R.id.list_dir);
list.setAdapter(Adapter);
list.setOnItemClickListener(lvLis);
home = (Button) findViewById(R.id.btn_home);
home.setOnClickListener(this);
back = (Button) findViewById(R.id.btn_back);
back.setOnClickListener(this);
ok = (Button) findViewById(R.id.btn_ok);
ok.setOnClickListener(this);
titleView = (LinearLayout) findViewById(R.id.dir_layout);
if(type == TypeOpen){
title = new TextView(context);
titleView.addView(title);
title.setText(path);
}else if(type == TypeSave){
et = new EditText(context);
et.setWidth(240);
et.setHeight(70);
et.setGravity(Gravity.CENTER);
et.setPadding(0, 2, 0, 0);
titleView.addView(et);
et.setText("wfFileName");
}
// title = (TextView) findViewById(R.id.dir_str);
// title.setText(path);
}
//动态更新ListView
Runnable add=new Runnable(){
@Override
public void run() {
// TODO Auto-generated method stub
arr.clear();
//System.out.println("Runnable path:"+path);
//必须得用这种方法为arr赋值才能更新
List temp = getDirs(path);
for(int i = 0;i < temp.size();i++)
arr.add(temp.get(i));
Adapter.notifyDataSetChanged();
}
};
private OnItemClickListener lvLis=new OnItemClickListener(){
@Override
public void onItemClick(AdapterView arg0, View arg1, int arg2,
long arg3) {
String temp = (String) arg0.getItemAtPosition(arg2);
//System.out.println("OnItemClick path1:"+path);
if(temp.equals(".."))
path = getSubDir(path);
else if(path.equals("/"))
path = path+temp;
else
path = path+"/"+temp;
//System.out.println("OnItemClick path2"+path);
if(type == TypeOpen)
title.setText(path);
Handler handler=new Handler();
handler.post(add);
}
};
private List getDirs(String ipath){
List file = new ArrayList();
//System.out.println("GetDirs path:"+ipath);
File[] myFile = new File(ipath).listFiles();
if(myFile == null){
file.add("..");
}else
for(File f: myFile){
//过滤目录
if(f.isDirectory()){
String tempf = f.toString();
int pos = tempf.lastIndexOf("/");
String subTemp = tempf.substring(pos+1, tempf.length());
// String subTemp = tempf.substring(path.length(),tempf.length());
file.add(subTemp);
//System.out.println("files in dir:"+subTemp);
}
//过滤知道类型的文件
if(f.isFile() && fileType != null){
for(int i = 0;i< fileType.length;i++){
int typeStrLen = fileType[i].length();
String fileName = f.getPath().substring(f.getPath().length()- typeStrLen);
if (fileName.toLowerCase().equals(fileType[i])) {
file.add(f.toString().substring(path.length()+1,f.toString().length()));
}
}
}
}
if(file.size()==0)
file.add("..");
// System.out.println("file[0]:"+file.get(0)+" File size:"+file.size());
return file;
}
/* (non-Javadoc)
* @see android.view.View.OnClickListener#onClick(android.view.View)
*/
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if(v.getId() == home.getId()){
path = getRootDir();
if(type == TypeOpen)
title.setText(path);
Handler handler=new Handler();
handler.post(add);
}else if(v.getId() == back.getId()){
path = getSubDir(path);
if(type == TypeOpen)
title.setText(path);
Handler handler=new Handler();
handler.post(add);
}else if(v.getId() == ok.getId()){
dismiss();
if(type == TypeSave)
path = path+"/"+et.getEditableText().toString()+".wf";
Toast.makeText(context, path, Toast.LENGTH_SHORT).show();
}
}
private String getSDPath(){
File sdDir = null;
boolean sdCardExist = Environment.getExternalStorageState()
.equals(android.os.Environment.MEDIA_MOUNTED); //判断sd卡是否存在
if(sdCardExist)
{
sdDir = Environment.getExternalStorageDirectory();//获取根目录
}
if(sdDir == null){
//Toast.makeText(context, "No SDCard inside!",Toast.LENGTH_SHORT).show();
return null;
}
return sdDir.toString();
}
private String getRootDir(){
String root = "/";
path = getSDPath();
if (path == null)
path="/";
return root;
}
private String getSubDir(String path){
String subpath = null;
int pos = path.lastIndexOf("/");
if(pos == path.length()){
path = path.substring(0,path.length()-1);
pos = path.lastIndexOf("/");
}
subpath = path.substring(0,pos);
if(pos == 0)
subpath = path;
return subpath;
}
}
package hkp.dirchooser;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn = (Button) findViewById(R.id.btn_open);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String path = null;
String [] fileType = {"dst"};//要过滤的文件类型列表
DirChooserDialog dlg = new DirChooserDialog(MainActivity.this,2,fileType,path);
dlg.setTitle("Choose dst file dir");
dlg.show();
}
});
}
}