非常简单的Android打开和保存对话框功能

在android上没有标准的打开和另存为对话框。在本代码中,我将详细描述一个非常简单的打开和保存对话框实现过程,对于android初学者来说非常有用，对话框都是全屏活动的。

主要功能：

1、访问任何目录的sd卡
2、递归访问文件夹
3、单一文件选择
4、通过按硬件后退按钮升级
5、确认文件选择ok按钮 

activity_open_file.xml

<linearlayout xmlns:android="<a href="http://schemas.android.com/apk/res/android"" rel="nofollow" target="_blank">http://schemas.android.com/apk/res/android"</a>
  xmlns:tools="<a href="http://schemas.android.com/tools"" rel="nofollow" target="_blank">http://schemas.android.com/tools"</a>
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" >

  <listview
    android:id="@+id/lvlist"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1" >

  </listview>
  <linearlayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

    <button
      android:id="@+id/btnok"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="ok" />
    <button
      android:id="@+id/btncancel"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:layout_weight="1"
      android:text="cancel" />

  </linearlayout>
</linearlayout>

openfileactivity.java

package com.example.androidfiledialogs;

import java.io.file;
import java.util.arraylist;
import java.util.collections;
import java.util.comparator;
import android.app.activity;
import android.content.intent;
import android.os.bundle;
import android.os.environment;
import android.view.menu;
import android.view.menuitem;
import android.view.view;
import android.view.view.onclicklistener;
import android.widget.adapterview;
import android.widget.adapterview.onitemclicklistener;
import android.widget.adapterview.onitemlongclicklistener;
import android.widget.adapterview.onitemselectedlistener;
import android.widget.arrayadapter;
import android.widget.button;
import android.widget.listview;
import android.widget.spinner;
import android.widget.toast;


public class openfileactivity extends activity
  implements onclicklistener, onitemclicklistener {
  listview lvlist;
  arraylist<string> listitems = new arraylist<string>();
  arrayadapter<string> adapter;
  button btnok;
  button btncancel;
  string currentpath = null;
  string selectedfilepath = null; /* full path, i.e. /mnt/sdcard/folder/file.txt */
  string selectedfilename = null; /* file name only, i.e file.txt */
  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_open_file);
    try {

      /* initializing widgets */
      lvlist = (listview) findviewbyid(r.id.lvlist);
      btnok = (button) findviewbyid(r.id.btnok);
      btncancel = (button) findviewbyid(r.id.btncancel);    

      /* initializing event handlers */
      lvlist.setonitemclicklistener(this);
      btnok.setonclicklistener(this);
      btncancel.setonclicklistener(this);

      //
    setcurrentpath(environment.getexternalstoragedirectory().getabsolutepath() + "/");
    } catch (exception ex) {
      toast.maketext(this,
          "error in openfileactivity.oncreate: " + ex.getmessage(),
          toast.length_short).show();
    }

  }

  void setcurrentpath(string path) {
    arraylist<string> folders = new arraylist<string>();
    arraylist<string> files = new arraylist<string>();
    currentpath = path;
    file allentries = new file(path).listfiles();
    for (int i = 0; i < allentries.length; i++) {
      if (allentries.isdirectory()) {
        folders.add(allentries.getname());
      } else if (allentries.isfile()) {
        files.add(allentries.getname());
      }
    }

    collections.sort(folders, new comparator<string>() {
      @override
      public int compare(string s1, string s2) {
        return s1.comparetoignorecase(s2);
      }
    });

     collections.sort(files, new comparator<string>() {
      @override
      public int compare(string s1, string s2) {
        return s1.comparetoignorecase(s2);

      }

    });

    listitems.clear();
    for (int i = 0; i < folders.size(); i++) {
      listitems.add(folders.get(i) + "/");
    }

    for (int i = 0; i < files.size(); i++) {
      listitems.add(files.get(i));

    }

    

    adapter = new arrayadapter<string>(this,

        android.r.layout.simple_list_item_1,

        listitems);

    adapter.notifydatasetchanged();

    

    lvlist.setadapter(adapter);

  }

  

  @override

  public void onbackpressed()

  {

    if (!currentpath.equals(environment.getexternalstoragedirectory().getabsolutepath() + "/")) {

      setcurrentpath(new file(currentpath).getparent() + "/");

    } else {

      super.onbackpressed();

    }

  }

  

  @override

  public void onclick(view v) {

    intent intent;

    

    switch (v.getid()) {

    case r.id.btnok:

      

      intent = new intent();

      intent.putextra("filename", selectedfilepath);

      intent.putextra("shortfilename", selectedfilename);

      setresult(result_ok, intent);

      

      this.finish();

      

      break;

    case r.id.btncancel:

      

      intent = new intent();

      intent.putextra("filename", "");

      intent.putextra("shortfilename", "");

      setresult(result_canceled, intent);

      

      this.finish();

      

      break;

    }

  }


  @override

  public void onitemclick(adapterview<?> parent, view view, int position,

      long id) {

    string entryname = (string)parent.getitematposition(position);

    if (entryname.endswith("/")) {

      setcurrentpath(currentpath + entryname);

    } else {

      selectedfilepath = currentpath + entryname;

      

      selectedfilename = entryname;

      

      this.settitle(this.getresources().getstring(r.string.title_activity_open_file)

          + "<span>[</span>" + entryname + "]");

    }

  }

}

activity_save_file.xml

<linearlayout xmlns:android="<a href="http://schemas.android.com/apk/res/android"" rel="nofollow" target="_blank">http://schemas.android.com/apk/res/android"</a>

  xmlns:tools="<a href="http://schemas.android.com/tools"" rel="nofollow" target="_blank">http://schemas.android.com/tools"</a>

  android:layout_width="match_parent"

  android:layout_height="match_parent"

  android:orientation="vertical" >


  <listview

    android:id="@+id/sfa_lvlist"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:layout_weight="1" >

  </listview>


  <edittext

    android:id="@+id/sfa_txtfilename"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:ems="10"

    android:text="file.txt" />

  

  <linearlayout

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    android:orientation="horizontal" >


    <button

      android:id="@+id/sfa_btnok"

      android:layout_width="fill_parent"

      android:layout_height="wrap_content"

      android:layout_weight="1"

      android:text="ok" />


    <button

      android:id="@+id/sfa_btncancel"

      android:layout_width="fill_parent"

      android:layout_height="wrap_content"

      android:layout_weight="1"

      android:text="cancel" />

    

  </linearlayout>

    

</linearlayout>
</linearlayout>

savefileactivity.java

package com.example.androidfiledialogs;

import java.io.file;
import java.util.arraylist;

import java.util.collections;

import java.util.comparator;


import android.app.activity;

import android.content.intent;

import android.os.bundle;

import android.os.environment;

import android.view.menu;

import android.view.menuitem;

import android.view.view;

import android.view.view.onclicklistener;

import android.widget.adapterview;

import android.widget.arrayadapter;

import android.widget.button;

import android.widget.edittext;

import android.widget.listview;

import android.widget.toast;

import android.widget.adapterview.onitemclicklistener;


public class savefileactivity extends activity

  implements onclicklistener, onitemclicklistener {


    listview lvlist;

    

    arraylist<string> listitems = new arraylist<string>();

    

    arrayadapter<string> adapter;

    

    edittext txtfilename;

    

    button btnok;

    button btncancel;

    

    string currentpath = null;

    

  @override

  protected void oncreate(bundle savedinstancestate) {

    super.oncreate(savedinstancestate);

    setcontentview(r.layout.activity_save_file);

    

    try {

      /* initializing widgets */

      lvlist = (listview) findviewbyid(r.id.sfa_lvlist);

      txtfilename = (edittext) findviewbyid(r.id.sfa_txtfilename);

      btnok = (button) findviewbyid(r.id.sfa_btnok);

      btncancel = (button) findviewbyid(r.id.sfa_btncancel);

      

      /* initializing event handlers */

      

      lvlist.setonitemclicklistener(this);

      

      btnok.setonclicklistener(this);

      btncancel.setonclicklistener(this);

      

      //

      

      setcurrentpath(environment.getexternalstoragedirectory().getabsolutepath() + "/");

    } catch (exception ex) {

      toast.maketext(this,

          "error in savefileactivity.oncreate: " + ex.getmessage(),

          toast.length_short).show();

    }

  }

  

  void setcurrentpath(string path) {

    arraylist<string> folders = new arraylist<string>();

    

    arraylist<string> files = new arraylist<string>();

    

    currentpath = path;

    

    file allentries = new file(path).listfiles();

    

    for (int i = 0; i < allentries.length; i++) {

      if (allentries.isdirectory()) {

        folders.add(allentries.getname());

      } else if (allentries.isfile()) {

        files.add(allentries.getname());

      }

    }

    

    collections.sort(folders, new comparator<string>() {

      @override

      public int compare(string s1, string s2) {

        return s1.comparetoignorecase(s2);

      }

    });

    

    collections.sort(files, new comparator<string>() {

      @override

      public int compare(string s1, string s2) {

        return s1.comparetoignorecase(s2);

      }

    });

    

    listitems.clear();

    

    for (int i = 0; i < folders.size(); i++) {

      listitems.add(folders.get(i) + "/");

    }

    

    for (int i = 0; i < files.size(); i++) {

      listitems.add(files.get(i));

    }

    

    adapter = new arrayadapter<string>(this,

        android.r.layout.simple_list_item_1,

        listitems);

    adapter.notifydatasetchanged();

    

    lvlist.setadapter(adapter);

  }

  

  @override

  public void onbackpressed()

  {

    if (!currentpath.equals(environment.getexternalstoragedirectory().getabsolutepath() + "/")) {

      setcurrentpath(new file(currentpath).getparent() + "/");

    } else {

      super.onbackpressed();

    }

  }

  

  @override

  public void onclick(view v) {

    intent intent;

    

    switch (v.getid()) {

    case r.id.sfa_btnok:

      

      intent = new intent();

      intent.putextra("filename", currentpath + txtfilename.gettext().tostring());

      intent.putextra("shortfilename", txtfilename.gettext().tostring());

      setresult(result_ok, intent);

      

      this.finish();

      

      break;

    case r.id.sfa_btncancel:

      

      intent = new intent();

      intent.putextra("filename", "");

      intent.putextra("shortfilename", "");

      setresult(result_canceled, intent);

      

      this.finish();

      

      break;

    }

  }


  @override

  public void onitemclick(adapterview<?> parent, view view, int position,

      long id) {

    string entryname = (string)parent.getitematposition(position);

    if (entryname.endswith("/")) {

      setcurrentpath(currentpath + entryname);

    } else {

      this.settitle(this.getresources().getstring(r.string.title_activity_open_file)

          + "<span>[</span>" + entryname + "]");

      

      txtfilename.settext(entryname);

    }

  }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。