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 。
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public class copyoffilechooseractivity extends activity { private string msdcardrootpath ; //sdcard 根路径 private string mlastfilepath ; //当前显示的路径 private arraylist<fileinfo> 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<fileinfo>() ; 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，囧 ，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
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<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <linearlayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="40dip"> <button android:layout_width="40dip" android:layout_height="40dip" android:text="home" android:id="@+id/btn_home" android:layout_gravity="left" android:layout_weight="1" /> <linearlayout android:layout_width="140dip" android:layout_height="35dip" android:id="@+id/dir_layout" android:gravity="center" android:layout_weight="1"> </linearlayout> <!-- <textview android:layout_width="140dip" android:layout_height="35dip" android:id="@+id/dir_str" android:gravity="center" android:layout_weight="1" /> --> <button android:layout_width="40dip" android:layout_height="40dip" android:text="back" android:id="@+id/btn_back" android:layout_gravity="right" android:layout_weight="1" /> </linearlayout> <listview android:layout_width="fill_parent" android:layout_height="300dip" android:id="@+id/list_dir" /> <button android:layout_width="fill_parent" android:layout_height="wrap_content" android:id="@+id/btn_ok" android:text="ok"/> </linearlayout> |
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package hkp.dirchooser;
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import java.io.file;
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import java.util.arraylist;
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import java.util.list;
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import android.app.dialog;
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import android.content.context;
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import android.os.bundle;
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import android.os.environment;
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import android.os.handler;
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import android.view.gravity;
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import android.view.view;
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import android.widget.adapterview;
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import android.widget.adapterview.onitemclicklistener;
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import android.widget.arrayadapter;
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import android.widget.button;
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import android.widget.edittext;
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import android.widget.linearlayout;
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import android.widget.listview;
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import android.widget.textview;
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import android.widget.toast;
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public class dirchooserdialog extends dialog implements android.view.view.onclicklistener{
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private listview list;
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arrayadapter<string> adapter;
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arraylist<string> arr=new arraylist<string>();
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context context;
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private string path;
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private textview title;
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private edittext et;
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private button home,back,ok;
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private linearlayout titleview;
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private int type = 1;
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private string[] filetype = null;
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public final static int typeopen = 1;
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public final static int typesave = 2;
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/**
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* @param context
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* @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
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* @param filetype 要过滤的文件类型,null表示只选择目录
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* @param resultpath 点ok按钮返回的结果，目录或者目录+文件名
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*/
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public dirchooserdialog(context context,int type,string[]filetype,string resultpath) {
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super(context);
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// todo auto-generated constructor stub
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this.context = context;
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this.type = type;
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this.filetype = filetype;
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this.path = resultpath;
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}
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/* (non-javadoc)
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* @see android.app.dialog#dismiss()
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*/
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@override
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public void dismiss() {
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// todo auto-generated method stub
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super.dismiss();
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}
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/* (non-javadoc)
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* @see android.app.dialog#oncreate(android.os.bundle)
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*/
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@override
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protected void oncreate(bundle savedinstancestate) {
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// todo auto-generated method stub
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super.oncreate(savedinstancestate);
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setcontentview(r.layout.chooserdialog);
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path = getrootdir();
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arr = (arraylist<string>) getdirs(path);
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adapter = new arrayadapter<string>(context,android.r.layout.simple_list_item_1, arr);
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list = (listview)findviewbyid(r.id.list_dir);
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list.setadapter(adapter);
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list.setonitemclicklistener(lvlis);
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home = (button) findviewbyid(r.id.btn_home);
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home.setonclicklistener(this);
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back = (button) findviewbyid(r.id.btn_back);
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back.setonclicklistener(this);
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ok = (button) findviewbyid(r.id.btn_ok);
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ok.setonclicklistener(this);
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titleview = (linearlayout) findviewbyid(r.id.dir_layout);
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if(type == typeopen){
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title = new textview(context);
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titleview.addview(title);
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title.settext(path);
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}else if(type == typesave){
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et = new edittext(context);
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et.setwidth(240);
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et.setheight(70);
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et.setgravity(gravity.center);
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et.setpadding(0, 2, 0, 0);
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titleview.addview(et);
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et.settext("wffilename");
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}
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// title = (textview) findviewbyid(r.id.dir_str);
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// title.settext(path);
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}
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//动态更新listview
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runnable add=new runnable(){
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@override
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public void run() {
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// todo auto-generated method stub
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arr.clear();
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//system.out.println("runnable path:"+path);
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//必须得用这种方法为arr赋值才能更新
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list<string> temp = getdirs(path);
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for(int i = 0;i < temp.size();i++)
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arr.add(temp.get(i));
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adapter.notifydatasetchanged();
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}
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};
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private onitemclicklistener lvlis=new onitemclicklistener(){
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@override
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public void onitemclick(adapterview<?> arg0, view arg1, int arg2,
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long arg3) {
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string temp = (string) arg0.getitematposition(arg2);
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//system.out.println("onitemclick path1:"+path);
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if(temp.equals(".."))
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path = getsubdir(path);
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else if(path.equals("/"))
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path = path+temp;
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else
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path = path+"/"+temp;
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//system.out.println("onitemclick path2"+path);
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if(type == typeopen)
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title.settext(path);
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handler handler=new handler();
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handler.post(add);
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}
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};
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private list<string> getdirs(string ipath){
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list<string> file = new arraylist<string>();
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//system.out.println("getdirs path:"+ipath);
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file[] myfile = new file(ipath).listfiles();
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if(myfile == null){
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file.add("..");
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}else
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for(file f: myfile){
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//过滤目录
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if(f.isdirectory()){
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string tempf = f.tostring();
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int pos = tempf.lastindexof("/");
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string subtemp = tempf.substring(pos+1, tempf.length());
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// string subtemp = tempf.substring(path.length(),tempf.length());
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file.add(subtemp);
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//system.out.println("files in dir:"+subtemp);
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}
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//过滤知道类型的文件
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if(f.isfile() && filetype != null){
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for(int i = 0;i< filetype.length;i++){
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int typestrlen = filetype[i].length();
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string filename = f.getpath().substring(f.getpath().length()- typestrlen);
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if (filename.tolowercase().equals(filetype[i])) {
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file.add(f.tostring().substring(path.length()+1,f.tostring().length()));
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}
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}
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}
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}
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if(file.size()==0)
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file.add("..");
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// system.out.println("file[0]:"+file.get(0)+" file size:"+file.size());
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return file;
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}
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/* (non-javadoc)
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* @see android.view.view.onclicklistener#onclick(android.view.view)
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*/
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@override
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public void onclick(view v) {
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// todo auto-generated method stub
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if(v.getid() == home.getid()){
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path = getrootdir();
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if(type == typeopen)
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title.settext(path);
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handler handler=new handler();
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handler.post(add);
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}else if(v.getid() == back.getid()){
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path = getsubdir(path);
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if(type == typeopen)
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title.settext(path);
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handler handler=new handler();
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handler.post(add);
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}else if(v.getid() == ok.getid()){
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dismiss();
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if(type == typesave)
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path = path+"/"+et.geteditabletext().tostring()+".wf";
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toast.maketext(context, path, toast.length_short).show();
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}
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}
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private string getsdpath(){
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file sddir = null;
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boolean sdcardexist = environment.getexternalstoragestate()
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.equals(android.os.environment.media_mounted); //判断sd卡是否存在
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if(sdcardexist)
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{
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sddir = environment.getexternalstoragedirectory();//获取根目录
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}
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if(sddir == null){
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//toast.maketext(context, "no sdcard inside!",toast.length_short).show();
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return null;
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}
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return sddir.tostring();
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}
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private string getrootdir(){
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string root = "/";
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path = getsdpath();
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if (path == null)
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path="/";
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return root;
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}
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private string getsubdir(string path){
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string subpath = null;
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int pos = path.lastindexof("/");
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if(pos == path.length()){
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path = path.substring(0,path.length()-1);
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pos = path.lastindexof("/");
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}
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subpath = path.substring(0,pos);
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if(pos == 0)
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subpath = path;
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return subpath;
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}
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}
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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(); } }); } } |
