android选择文件（安卓系统文件夹详解）

废话没有，先看效果

第一步：创建mainactivity

import android.app.activity;import android.content.context;import android.content.intent;import android.os.bundle;import android.view.view;import android.widget.button;import android.widget.textview;import com.rdsa.singlelectedfileorfolder.r;import java.util.arraylist;public class mainactivity extends appcompatactivity {    public context mcontext;    private button lectfile, lectfolder, mlectfile, mlectfolder;    private textview result;    private activity activity;    @override    protected void oncreate(bundle savedinstancestate) {        super.oncreate(savedinstancestate);        this.mcontext = this;        this.activity = this;        tcontentview(r.layout.activity_main);        initview();        initdata();        initevent();    }    @override    protected void onactivityresult(int requestcode, int resultcode, intent data) {        super.onactivityresult(requestcode, resultcode, data);        if (requestcode == choofileordiractivity.requestcode && resultcode == choofileordiractivity.resultcode) {            arraylist<string> respath = data.getstringarraylistextra(choofileordiractivity.resultdata);            stringbuffer sb = new stringbuffer();            for(string item : respath) {                sb.append(item).append("rn");            }            result.ttext(sb.tostring());        }    }    private void initview() {        this.result = super.findviewbyid(r.id.result);        this.lectfile = super.findviewbyid(r.id.lectfile);        this.lectfolder = super.findviewbyid(r.id.lectfolder);        this.mlectfile = super.findviewbyid(r.id.mlectfile);        this.mlectfolder = super.findviewbyid(r.id.mlectfolder);    }    private void initdata() {    }    private void initevent() {        lectfile.tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                intent intent = new intent(activity, choofileordiractivity.class);                intent.putextra(choofileordiractivity.entervar, choofileordiractivity.singlefile);                activity.startactivityforresult(intent, choofileordiractivity.requestcode);            }        });        lectfolder.tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                intent intent = new intent(activity, choofileordiractivity.class);                intent.putextra(choofileordiractivity.entervar, choofileordiractivity.singlefolder);                activity.startactivityforresult(intent, choofileordiractivity.requestcode);            }        });        mlectfile.tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                intent intent = new intent(activity, choofileordiractivity.class);                intent.putextra(choofileordiractivity.entervar, choofileordiractivity.multifile);                activity.startactivityforresult(intent, choofileordiractivity.requestcode);            }        });        mlectfolder.tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                intent intent = new intent(activity, choofileordiractivity.class);                intent.putextra(choofileordiractivity.entervar, choofileordiractivity.multifolder);                a夏天的成语ctivity.startactivityforresult(intent, choofileordiractivity.requestcode);            }        });    }}

第二步：创建mainactivity布局文件activity_main.xml

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context="com.rdsa.lectedfileorfolder.mainactivity">    <button        android:id="@+id/lectfolder"        android:text="文件夹选择(单选)"        android:layout_width="match_parent"        android:layout_height="wrap_content"   />    <button        android:id="@+id/lectfile"        android:text="文件选择（单选）"        android:layout_width="match_parent"        android:layout_height="wrap_content"   />    <button        android:id="@+id/mlectfolder"        android:text="文件夹选择(多选)"        android:layout_width="match_parent"        android:layout_height="wrap_content"   />    <button        android:id="@+id/mlectfile"        android:text="文件选择（多选）"        android:layout_width="match_parent"        android:layout_height="wrap_content"   />    <textview        android:id="@+id/result"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="wait for result" /></linearlayout>

第三步：创建目录数据存储类fileordirbeans

public class fileordirbeans {    string isfile, name, ischeckvisible, ischecked, absolutepath ;    public fileordirbeans(string... params) {        this.isfile = params[0];        this.name = params[1];        this.ischeckvisible = params[2];        this.ischecked = params[3];        this.absolutepath = params[4];    }    public string getisfile() {        return isfile;    }    public void tisfile(string isfile) {        this.isfile = isfile;    }    public string getname() {        return name;    }    public void tname(string name) {        this.name = name;    }    public string getischeckvisible() {        return ischeckvisible;    }    public void tischeckvisible(string ischeckvisible) {        this.ischeckvisible = ischeckvisible;    }    public string getischecked() {        return ischecked;    }    public void tischecked(string ischecked) {        this.ischecked = ischecked;    }    public string getabsolutepath() {        return absolutepath;    }    public void tabsolutepath(string absolutepath) {        this.absolutepath = absolutepath;    }}

第四步：创建文件浏览choofileordiractivity

import android.manifest;import android.app.activity;import android.content.intent;import android.content.pm.packagemanager;import android.os.build;import android.os.bundle;import android.os.environment;import android.view.keyevent;import android.view.view;import android.widget.button;import android.widget.listview;import android.widget.textview;import com.rdsa.singlelectedfileorfolder.r;import java.io.file;import java.util.arraylist;import java.util.arrays;import java.util.collections;import java.util.comparator;import java.util.list;public class choofileordiractivity extends activity {    public static final string entervar = "entervar";    public static final string resultdata = "lected";    public static final int requestcode = 888;    public static final int resultcode = 999;    public static final int singlefile = 1000;    public static final int singlefolder = 2000;    public static final int multifile = 3000;    public static final int multifolder = 2001;    private string rootpath = environment.getexternalstoragedirectory().getabsolutepath();    private static final int requescode = 5;    private static final string need_permission = manifest.permission.write_external_storage;    private listview listview4file;    private textview nodatatip;    private button btcho;    private list<string> data;    private arraylist<fileordirbeans> fileordirlist;    private fileadapter fileadapter;    private int entervar;    @override    protected void oncreate(bundle savedinstancestate) {        super.oncreate(savedinstancestate);        tcontentview(r.layout.ly_choo_file_or_folder);        this.entervar = this.getintent().getintextra(entervar, singlefile);        this.initview();        this.initdata();        this.initevent();    }    private void initdata() {        this.listview4file.temptyview(nodatatip);        this.data = new arraylist<>();        this.fileordirlist = new arraylist<>();        this.fileadapter = new fileadapter(this, fileordirlist, entervar);        this.listview4file.tadapter(fileadapter);        if (build.version.sdk_int >= 23) {      // 判断系统版本是否大于6.0            if (checklfpermission(need_permission) == packagemanager.permission_granted) {  //检查是否有读写权限                loaddatafrompath(rootpath, entervar);//从路径中加载数据            } el {                requestpermissions(new string[]{need_permission}, requescode); // 申请权限            }        } el {            loaddatafrompath(rootpath, entervar);//系统版本小于6.0直接加载数据        }    }    private void loaddatafrompath(final string mpath, final int type) {        this.data.clear();    // data为 listview 中要显示的数据        this.fileordirlist.clear();        new thread() {            public void run() {                super.run();                data = orderbyname(mpath, type == singlefolder || type == multifolder);                fileordirlist = getbeans(data, type);                runonuithread(new runnable() {                    @override                    public void run() {                        fileadapter.tdata(data, fileordirlist);//将数据载入适配器当中                    }                });            }        }.start();    }    private arraylist<filblou是什么意思eordirbeans> getbeans(list<string> filelist, final int type) {        arraylist<fileordirbeans> resultlist = new arraylist<>();        for(string fileitem : filelist) {            file file = new file(fileitem);            string isfile = string.valueof(file.isfile());            string ischeckvisible = (file.isfile() || type == singlefolder || type == multifolder) ?  "true" : "fal";;            fileordirbeans bean = new fileordirbeans(isfile, file.getname(), ischeckvisible, "fal", fileitem);            resultlist.add(bean);        }        return resultlist;    }    private void initview() {        listview4file = findviewbyid(r.id.rvfileview);        nodatatip = findviewbyid(r.id.nodatatip);    }    private void initevent() {        fileadapter.tevent(new fileadapter.event() {            @override            public void enternextdir(string path) {                rootpath = path;                loaddatafrompath(rootpath, entervar);            }        });        findviewbyid(r.id.btcho).tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                intent intent = new intent();                intent.putstringarraylistextra(resultdata, fileadapter.getlectdata());                tresult(resultcode, intent);                finish();            }        });    }    @override    public void onrequestpermissionsresult(int requestcode, string[] permissions, int[] grantresults) {        super.onrequestpermissionsresult(requestcode, permissions, grantresults);        if (requestcode == requescode && permissions[0].equals(need_permission)) {            loaddatafrompath(rootpath, entervar);        }    }    @override    public boolean onkeydown(int keycode, keyevent event) {        if (event.getkeycode() == keyevent.keycode_back) {//点击的是返回键            if (event.getaction() == keyevent.action_down && event.getrepeatcount() == 0) {//按键的按下事件                if (rootpath.trim().equals(environment.getexternalstoragedirectory().getabsolutepath())) {                    return super.onkeydown(keycode, event);                } el {                    file file = new file(rootpath);                    if (!file.exists()) {                        return super.onkeydown(keycode, event);                    }                    rootpath = file.getparent();                    loaddatafrompath(rootpath, entervar);                    return fal;                }            }        }        return super.onkeydown(keycode, event);    }    public static arraylist<string> orderbyname(string filepath, boolean excludefile) {        arraylist<string> filenamelist = new arraylist<string>();        file file = new file(filepath);        file[] files = file.listfiles();        list filelist = arrays.aslist(files);        collections.sort(filelist, new comparator<file>() {            @override            public int compare(file o1, file o2) {                if (o1.isdirectory() && o2.isfile())                    return -1;                if (o1.isfile() && o2.isdirectory())                    return 1;                return o1.getname().compareto(o2.getname());            }        });        for (file itemfile : files) {            if(itemfile.getname().startswith(".")) {                continue;            } el {                if(itemfile.isfile() && excludefile) {                    continue;                }                filenamelist.add(itemfile.getabsolutepath());  //往集合中添加符合条件的数据            }        }        return filenamelist;    }}

第五步：创惯性是力吗建choofileordiractivity布局文件
ly_choo_file_or_folder.xml

<?xml version="1.0" encoding="utf-8"?><linearlayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <relativelayout        android:layout_width="match_parent"        android:layout_height="50dp"        android:background="#f9f9fa">        <textview            android:id="@+id/tvtitle"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_centerinparent="true" />        <button            android:id="@+id/btcho"            android:layout_width="wrap_content"            android:layout_height="30dp"            android:layout_alignparentright="true"     孕妇感冒鼻塞       android:layout_centervertical="true"            android:layout_marginright="5dp"            android:background="@drawable/bg_button"            android:text="确定"            android:textcolor="#458b74" />    </relativelayout>    <listview        android:id="@+id/rvfileview"        android:layout_width="match_parent"        android:layout_height="match_parent" />    <textview        android:id="@+id/nodatatip"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_vertical|center_horizontal"        android:text="没有数据可用，返回上一层" /></linearlayout>

第六步：创建listview的数据容器类fileada最小的质数是pter

import android.content.context;import android.view.layoutinflater;import android.view.view;import android.view.viewgroup;import android.widget.baadapter;import android.widget.checkbox;import android.widget.compoundbutton;import android.widget.imageview;import android.widget.textview;import com.rdsa.singlelectedfileorfolder.r;import java.util.arraylist;import java.util.list;public class fileadapter extends baadapter {    private context context;    private event event;    private arraylist<string> lectdata;    private arraylist<fileordirbeans> fileordirlist;    private layoutinflater mlayoutinflater;      //   将 item 的 xml 转换成 view    private final int entervar;    public fileadapter(context context, final arraylist<fileordirbeans> fileordirlist, int entervar) {        this.context = context;        this.lectdata = new arraylist<>();        this.mlayoutinflater = layoutinflater.from(context);     // context 必须是界面所在的 context        this.entervar = entervar;        this.fileordirlist = fileordirlist;    }    @override    public int getcount() {        return this.fileordirlist.size();    }    @override     // 数据项    public object getitem(int position) {        return fileordirlist.get(position);    }    @override    public long getitemid(int position) {        return position;    }    @override    // 显示的内容    public view getview(final int position, view convertview, viewgroup viewgroup) {        viewholder viewholder;        if(convertview == null) {            convertview = mlayoutinflater.inflate(r.layout.filechoo_layout_fileitme, null);            viewholder = new viewholder();            viewholder.icon = convertview.findviewbyid(r.id.icon);            viewholder.filename = convertview.findviewbyid(r.id.filename);            viewholder.checkbox = convertview.findviewbyid(r.id.checkbox);            convertview.ttag(viewholder);        } el {            viewholder = (viewholder)convertview.gettag();        }        final fileordirbeans bean = fileordirlist.get(position);        final string abspath = bean.getabsolutepath();        bean.tischecked("fal");    //   初始化一个boolean值 来判断是否被选中        for (string s : lectdata) {    // 遍历选中的集合            if (s.trim().equals(abspath)) {    // 如果集合中的子元素与适配其中的路径相同                bean.tischecked("true");     // 判断已被选中                break; //终止循环            }        }        viewholder.checkbox.toncheckedchangelistener(new compoundbutton.oncheckedchangelistener() {            @override            public void oncheckedchanged(compoundbutton compoundbutton, boolean ischecked) {//设置checkbox的点击事件                if (ischecked) {//选中状态                    if (lectdata.contains(abspath)) {//如果集合中包含了该元素则直接返回                        if (entervar == choofileordiractivity.singlefile || entervar == choofileordiractivity.singlefolder) {                            lectdata.clear();                            lectdata.add(abspath);                        }                    } el {//否则添加                        if(entervar == choofileordiractivity.singlefile || entervar == choofileordiractivity.singlefolder) {                            lectdata.clear();                        }                        lectdata.add(abspath);                    }                } el {//未选中状态                    if (lectdata.contains(abspath)) {//如果集合中包含了该元素则移除                        lectdata.remove(abspath);                    } el {//否则 返回                        return;                    }                }                notifydatatchanged();            }        });        viewholder.icon.timagedrawable(boolean.parboolean(bean.getisfile()) ?  context.getresources().getdrawable(r.drawable._16_file) : context.getresources().getdrawable(r.drawable._16_folder));        viewholder.filename.ttext(bean.getname());        viewholder.checkbox.tvisibility((boolean.parboolean(bean.ischeckvisible))?  view.visible : view.gone);        viewholder.checkbox.tchecked(boolean.parboolean(bean.getischecked()));        viewholder.filename.tonclicklistener(new view.onclicklistener() {            @override            public void onclick(view view) {                if(!boolean.parboolean(bean.getisfile())) {                    event.enternextdir(fileordirlist.get(position).getabsolutepath());                }            }        });        return convertview;    }    static class viewholder {        private imageview icon;        private textview filename;        private checkbox checkbox;    }    public interface event {        void enternextdir(string path);//进入下一个文件夹    }    public void tdata(list<string> data, arraylist<fileordirbeans> fileordirlist) {        this.fileordirlist.clear();        this.fileordirlist.addall(fileordirlist);        notifydatatchanged();    }    public void tevent(event event) {        this.event = event;    }    public arraylist<string> getlectdata() {        return lectdata;    }}

第七步：创建fileadapter每一项的布局文件
filechoo_layout_fileitme.xml

<?xml version="1.0" encoding="utf-8"?><relativelayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="horizontal" >    <imageview        android:id="@+id/icon"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginstart="8dp"        android:layout_marginend="8dp"        android:layout_alignparentstart="true"        android:layout_centervertical="true"        android:src="@drawable/file" />    <textview        android:id="@+id/filename"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginbottom="8dp"        android:layout_margintop="8dp"        android:paddingright="50dp"        android:layout_torightof="@+id/icon"        android:layout_centervertical="true"        android:text="textview"  />    <checkbox        android:id="@+id/checkbox"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignparentend="true"        android:layout_centervertical="true"        android:layout_marginend="8dp" /></relativelayout>

第八步：androidmanifest 增加对文件操作的授权

<us-permission android:name="android.permission.read_external_storage" /><us-permission android:name="android.permission.write_external_storage" />

第九步：用到的图片资源_16_file.png和_16_folder.png