android数据存储之文件存储方法
文件存储是 android 中最基本的一种数据存储方式,它不对存储的内容进行任何的格式化处理,所有数据都是原封不动的保存到文件当中的。
概述
文件存取的核心就是输入流和输出流。
android文件的操作模式
文件的相关操作方法
文件读写的实现
openfileoutput和openfileinput方法
/** * openfileoutput ,openfileinput * 这两种方法同sp一样只能讲文件保存到手机内存固定的路径中, * 默认为 /data/data/<packagename>/files */ private void save2file() { try { //向文件写入内容 fileoutputstream os = openfileoutput("file.txt", context.mode_private); string text = "写数据到文件"; os.write(text.getbytes("utf-8")); //关闭流 os.close(); } catch (filenotfoundexception e) { e.printstacktrace(); } catch (unsupportedencodingexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } } /** * */ private void readfile() { try { fileinputstream ins = openfileinput("file.txt"); byte[] buffer = new byte[100]; int bytecount = ins.read(buffer); string text = new string(buffer,0,bytecount,"utf-8"); toast.maketext(this,text,toast.length_short).show(); ins.close(); } catch (filenotfoundexception e) { e.printstacktrace(); } catch (ioexception e) { e.printstacktrace(); } }
文件存储位置
/data/data/<package-name>/files
目录下
openfileoutput和openfileinput方法可以获得操作文件的outputstream以及inputstream对象,而且可以通过流对象处理任何文件的数据,但是这两个方法同sharedpreferences一样,只能在手机内存卡的指定目录建立文件,因此在使用上仍然有一定的局限性。
读取sd卡上的文件
main_activity.xml:
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/linearlayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="com.jay.example.filedemo2.mainactivity"> <textview android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="清输入文件名" /> <edittext android:id="@+id/edittitle" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="文件名" /> <textview android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="清输入文件内容" /> <edittext android:id="@+id/editdetail" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="文件内容" /> <button android:id="@+id/btnsave" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="保存到sd卡" /> <button android:id="@+id/btnclean" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="清空" /> <button android:id="@+id/btnread" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="读取sd卡中的文件" /> </linearlayout>
接着我们来写一个sd操作类: sdfilehelper.java
public class sdfilehelper { private context context; public sdfilehelper() { } public sdfilehelper(context context) { super(); this.context = context; } //往sd卡写入文件的方法 public void savafiletosd(string filename, string filecontent) throws exception { //如果手机已插入sd卡,且app具有读写sd卡的权限 if (environment.getexternalstoragestate().equals(environment.media_mounted)) { filename = environment.getexternalstoragedirectory().getcanonicalpath() + "/" + filename; //这里就不要用openfileoutput了,那个是往手机内存中写数据的 fileoutputstream output = new fileoutputstream(filename); output.write(filecontent.getbytes()); //将string字符串以字节流的形式写入到输出流中 output.close(); //关闭输出流 } else toast.maketext(context, "sd卡不存在或者不可读写", toast.length_short).show(); } //读取sd卡中文件的方法 //定义读取文件的方法: public string readfromsd(string filename) throws ioexception { stringbuilder sb = new stringbuilder(""); if (environment.getexternalstoragestate().equals(environment.media_mounted)) { filename = environment.getexternalstoragedirectory().getcanonicalpath() + "/" + filename; //打开文件输入流 fileinputstream input = new fileinputstream(filename); byte[] temp = new byte[1024]; int len = 0; //读取文件内容: while ((len = input.read(temp)) > 0) { sb.append(new string(temp, 0, len)); } //关闭输入流 input.close(); } return sb.tostring(); } }
接着mainactivity.java实现相关逻辑:
public class mainactivity extends appcompatactivity implements view.onclicklistener{ private edittext editname; private edittext editdetail; private button btnsave; private button btnclean; private button btnread; private context mcontext; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); mcontext = getapplicationcontext(); bindviews(); } private void bindviews() { editname = (edittext) findviewbyid(r.id.edittitle); editdetail = (edittext) findviewbyid(r.id.editdetail); btnsave = (button) findviewbyid(r.id.btnsave); btnclean = (button) findviewbyid(r.id.btnclean); btnread = (button) findviewbyid(r.id.btnread); btnsave.setonclicklistener(this); btnclean.setonclicklistener(this); btnread.setonclicklistener(this); } @override public void onclick(view v) { switch (v.getid()){ case r.id.btnclean: editdetail.settext(""); editname.settext(""); break; case r.id.btnsave: string filename = editname.gettext().tostring(); string filedetail = editdetail.gettext().tostring(); sdfilehelper sdhelper = new sdfilehelper(mcontext); try { sdhelper.savafiletosd(filename, filedetail); toast.maketext(getapplicationcontext(), "数据写入成功", toast.length_short).show(); } catch(exception e){ e.printstacktrace(); toast.maketext(getapplicationcontext(), "数据写入失败", toast.length_short).show(); } break; case r.id.btnread: string detail = ""; sdfilehelper sdhelper2 = new sdfilehelper(mcontext); try { string filename2 = editname.gettext().tostring(); detail = sdhelper2.readfromsd(filename2); } catch(ioexception e){e.printstacktrace();} toast.maketext(getapplicationcontext(), detail, toast.length_short).show(); break; } } }
最后别忘记在androidmanifest.xml写上读写sd卡的权限哦!
<!-- 在sdcard中创建与删除文件权限 --> <uses-permission android:name="android.permission.mount_unmount_filesystems"/> <!-- 往sdcard写入数据权限 --> <uses-permission android:name="android.permission.write_external_storage"/>
如何判断虚拟和物理两种sdk
在默认情况下,会将一部分存储空间分给虚拟的sd卡使用(一部分用于安装android操作系统)
android.os.enviroment.isexternalstorageremovalbe()
返回true:sd卡是物理的,反之sd卡是虚拟的。
用于适配不同型号手机,反射获取sd卡路径和状态
package com.turing.base.activity.datastore.filestore; import android.content.context; import android.os.environment; import android.os.statfs; import android.os.storage.storagemanager; import android.text.textutils; import android.util.log; import java.io.file; import java.lang.reflect.invocationtargetexception; import java.lang.reflect.method; import java.util.concurrent.concurrentlinkedqueue; import java.util.concurrent.executorservice; import java.util.concurrent.executors; /** * 用于适配不同型号手机,反射获取sd卡路径和状态 * */ public class devmountinfo { private final string tag = devmountinfo.class.getsimplename(); private static final int error = -1; // class name private final static string class_name = "android.os.storage.storagevolume"; //remained spare memory size private static final int remained_spare_in_mb = 100; // method name private final static string method_get_volume_list = "getvolumelist"; private final static string method_get_volume_state = "getvolumestate"; private final static string method_is_removable = "isremovable"; private final static string method_get_path = "getpath"; private final static string mounted = "mounted"; private static devmountinfo instance; private string msdcardpath = null; // internal file path private concurrentlinkedqueue<string> minternalpathlist = new concurrentlinkedqueue<string>(); // external file path private concurrentlinkedqueue<string> mexternalpathlist = new concurrentlinkedqueue<string>(); private executorservice mexecutor = null; private devmountinfo() { mexecutor = executors.newsinglethreadexecutor(); } public static devmountinfo getinstance() { synchronized (devmountinfo.class) { if (null == instance) { instance = new devmountinfo(); } return instance; } } @override protected void finalize() throws throwable { super.finalize(); synchronized (devmountinfo.class) { minternalpathlist.clear(); mexternalpathlist.clear(); mexecutor.shutdown(); instance = null; } } public void init(final context context) { mexecutor.execute(new runnable() { @override public void run() { executeinit(context); } }); } public boolean issdcardfull() { return remained_spare_in_mb > (getsdcardavailspace() * 1024); } public boolean issdcardavaiable() { return !mexternalpathlist.isempty() || !minternalpathlist.isempty(); } public string getsdcardpath() { return msdcardpath; } public long getsdcardtotalspace() { long totalspace = 0; if (!textutils.isempty(msdcardpath)) { statfs sf = new statfs(msdcardpath); long blocksize = sf.getblocksize(); long total = sf.getblockcount(); totalspace = total * blocksize / 1024; } return totalspace; } public long getsdcardavailspace() { long availspace = 0; if (!textutils.isempty(msdcardpath)) { statfs sf = new statfs(msdcardpath); long blocksize = sf.getblocksize(); long availcount = sf.getavailableblocks(); availspace = availcount * blocksize / 1024; } return availspace; } public string getinternalsdcardpath() { return minternalpathlist.peek(); } public string getexternalsdcardpath() { return mexternalpathlist.peek(); } private void executeinit(context context) { storagemanager mstoragemanager = (storagemanager) context.getsystemservice(context.storage_service); if (mstoragemanager != null) { class<?> mstoragevolume = null; method mgetvolumelistmethod = null; method mgetvolumestatemethod = null; method mgetpathmethod = null; method misremovablemethod = null; object[] mstoragevolumelist = null; try { mstoragevolume = class.forname(class_name); mgetvolumelistmethod = mstoragemanager.getclass().getmethod(method_get_volume_list, new class[0]); mgetvolumestatemethod = mstoragemanager.getclass().getmethod(method_get_volume_state, new class[]{string.class}); misremovablemethod = mstoragevolume.getmethod(method_is_removable, new class[0]); mgetpathmethod = mstoragevolume.getmethod(method_get_path, new class[0]); mstoragevolumelist = (object[]) mgetvolumelistmethod.invoke(mstoragemanager, new object[0]); boolean misremovable = false; if (mstoragevolumelist != null && mstoragevolumelist.length > 0) { int mstoragevolumecount = mstoragevolumelist.length; log.i(tag, "init() === > storagevolume count = " + mstoragevolumecount); minternalpathlist.clear(); mexternalpathlist.clear(); for (int i = 0; i < mstoragevolumecount; ++i) { string mstoragepath = (string) mgetpathmethod.invoke(mstoragevolumelist[i], new object[0]); misremovable = ((boolean) misremovablemethod.invoke(mstoragevolumelist[i], new object[0])).booleanvalue(); if (!textutils.isempty(mstoragepath)) { string state = (string) mgetvolumestatemethod.invoke(mstoragemanager, new object[]{mstoragepath}); if ((state != null) && (state.equals(mounted))) { if (misremovable) { log.i(tag, "init() === > external storage path = (" + mstoragepath + ")"); mexternalpathlist.add(mstoragepath); } else { log.i(tag, "init() === > internal storage path = (" + mstoragepath + ")"); minternalpathlist.add(mstoragepath); } } } } } } catch (classnotfoundexception e) { handleinvalid(); log.e(tag, "init() === > exception:classnotfoundexception"); } catch (nosuchmethodexception e) { handleinvalid(); log.e(tag, "init() === > exception:nosuchmethodexception"); } catch (illegalargumentexception e) { handleinvalid(); log.e(tag, "init() === > exception:illegalargumentexception"); } catch (illegalaccessexception e) { handleinvalid(); log.e(tag, "init() === > exception:illegalaccessexception"); } catch (invocationtargetexception e) { handleinvalid(); log.e(tag, "init() === > exception:invocationtargetexception"); } } else { handleinvalid(); log.e(tag, "init() === > can't get storage manager"); } initsdcardpath(); } private void handleinvalid() { minternalpathlist.add(environment.getexternalstoragedirectory().getpath()); } private void initsdcardpath() { if (!mexternalpathlist.isempty()) { msdcardpath = mexternalpathlist.peek(); } else if (!minternalpathlist.isempty()) { msdcardpath = minternalpathlist.peek(); } else { msdcardpath = environment.getexternalstoragedirectory().getpath(); } log.i(tag, "initsdcardpath() === > sdcard path = (" + msdcardpath + ")"); } /** * sdcard是否存 */ public static boolean externalmemoryavailable() { return android.os.environment.getexternalstoragestate().equals( android.os.environment.media_mounted); } /** * 获取手机内部剩余存储空间 * * @return */ public static long getavailableinternalmemorysize() { file path = environment.getdatadirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long availableblocks = stat.getavailableblocks(); return availableblocks * blocksize; } /** * 获取手机内部总的存储空间 * * @return */ public static long gettotalinternalmemorysize() { file path = environment.getdatadirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long totalblocks = stat.getblockcount(); return totalblocks * blocksize; } /** * 获取手机内置存储剩余存储空间 * * @return */ public static long getavailableinternalsystemmemorysize() { file path = environment.getrootdirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long availableblocks = stat.getavailableblocks(); return availableblocks * blocksize; } /** * 获取手机内置存储总的存储空间 * * @return */ public static long gettotalinternalsystemmemorysize() { file path = environment.getrootdirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long totalblocks = stat.getblockcount(); return totalblocks * blocksize; } /** * 获取sdcard剩余存储空间 * * @return */ public static long getavailableexternalmemorysize() { if (externalmemoryavailable()) { file path = environment.getexternalstoragedirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long availableblocks = stat.getavailableblocks(); return availableblocks * blocksize; } else { return error; } } /** * 获取sdcard总的存储空间 * * @return */ public static long gettotalexternalmemorysize() { if (externalmemoryavailable()) { file path = environment.getexternalstoragedirectory(); statfs stat = new statfs(path.getpath()); long blocksize = stat.getblocksize(); long totalblocks = stat.getblockcount(); return totalblocks * blocksize; } else { return error; } } public static long getavailablememorysize(string path) { if (null == path) return 0; statfs stat = new statfs(path); long blocksize = stat.getblocksize(); long availableblocks = stat.getavailableblocks(); return availableblocks * blocksize; } }
读取raw和assets文件夹下的文件
相信大家对两个文件夹并不陌生,如果我们不想自己的文件被编译成二进制文件的话, 我们可以把文件放到这两个目录下,而两者的区别如下:
- res/raw:文件会被映射到r.java文件中,访问的时候直接通过资源id即可访问,而且 他不能有目录结构,就是不能再创建文件夹
- assets:不会映射到r.java文件中,通过assetmanager来访问,能有目录结构,即, 可以自行创建文件夹。
读取文件资源:
res/raw:
inputstream is =getresources().openrawresource(r.raw.filename);
assets:
assetmanager am = getassets(); inputstream is = am.open("filename");
sax引擎读取xml文件
sax引擎读取xml文件的原理:
sax技术在处理xml文件时并不一次性把xml文件装入内存,而是一边读一般解析。
使用sax处理xml需要一个handler对象,一般会使用org.xml.sax.helpers.defaulthandler的子类作为handler对象
因此,这就需要处理如下5个分析点,也可称为分析事件:
- 开始分析xml文件。该分析点表示sax引擎刚开始处理xml文件,还没有读取xml文件中的内容。该分析点对应于defaulthandler类中的startdocument()事件方法,可以在该方法中做一下初始化的工作!
- 开始处理每一个xml元素,也就是遇到<product>,<item>这样的起始标记,sax引擎每次扫描到新的xml元素的起始标记会触发这个分析事件,对应的事件分析方法是startelement,在该方法中可以获取当前元素的名称和元素属性的相关信息
- 处理完一个xml元素,也就是遇到</product>,</item>这样的结束标记,该分析点对应的事件方法是endelement,在该事件中可以获得当前处理完的元素的全部信息。
- 处理完xml文件。如果sax引擎将整个xml文件的内容都扫描完了,就到了这个分析点,该分析点对应的事件方法enddocument(),该事件方法可能不是必需的,如果最后有以下收尾工作,如释放一下资源,可以在该方法中完成!
- 读取字符分析点。这是最重要的分析点。如果没有这个分析点,前4步的处理相当于白跑一遍,虽然读取了xml文件中的所有内容,但并未保存这些内容,而这个分析点所对应的characters事件方法的主要作用就是保存sax引擎读取的xml文件中的内容。更准确地说是保存xml元素的文本,也就是<product>abc</product>中的abc。
code
res\raw\product.xml
<?xml version="1.0" encoding="utf-8"?> <products> <product> <id>10</id> <name>电脑</name> <price>2067.25</price> </product> <product> <id>20</id> <name>微波炉</name> <price>520</price> </product> <product> <id>30</id> <name>洗衣机</name> <price>2400</price> </product> </products>
product.java
public class product { private int id; private string name; private float price; public int getid() { return id; } public void setid(int id) { this.id = id; } public string getname() { return name; } public void setname(string name) { this.name = name; } public float getprice() { return price; } public void setprice(float price) { this.price = price; } }
xml2product.java(defaulthandler子类)
defaulthandler子类 ,核心类,负责处理分析点事件。
import org.xml.sax.attributes; import org.xml.sax.saxexception; import org.xml.sax.helpers.defaulthandler; import java.util.arraylist; import java.util.list; public class xml2product extends defaulthandler { private list<product> products; private product product; private stringbuffer buffer = new stringbuffer(); public list<product> getproducts() { return products; } @override public void characters(char[] ch, int start, int length) throws saxexception { buffer.append(ch, start, length); super.characters(ch, start, length); } @override public void startdocument() throws saxexception { // 开始分析xml文件,创建list对象用于保存分析完的product对象 products = new arraylist<product>(); } @override public void startelement(string uri, string localname, string qname, attributes attributes) throws saxexception { if (localname.equals("product")) { // 如果分析的是<product>标签,则创建一个product对象 product = new product(); } super.startelement(uri, localname, qname, attributes); } @override public void endelement(string uri, string localname, string qname) throws saxexception { if (localname.equals("product")) { // 处理完 <product>标签后 将product对象添加到products中 products.add(product); } else if (localname.equals("id")) { // 设置id属性的值 product.setid(integer.parseint(buffer.tostring().trim())); // 将标签内容的缓存区清空 buffer.setlength(0); } else if (localname.equals("name")) { product.setname(buffer.tostring().trim()); buffer.setlength(0); } else if (localname.equals("price")) { product.setprice(float.parsefloat(buffer.tostring().trim())); buffer.setlength(0); } super.endelement(uri, localname, qname); } }
xml2javaobjectact
import android.app.alertdialog; import android.os.bundle; import android.support.v7.app.appcompatactivity; import android.util.xml; import android.view.view; import com.turing.base.r; import java.io.inputstream; import java.util.list; public class xml2javaobjectact extends appcompatactivity { @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_xml2_java_object); } public void onclick_xmltoobject(view view) { try { // 打开资源文件 inputstream is = getresources().openrawresource(r.raw.products); xml2product xml2product = new xml2product(); // 开始分析priducts.xml文件 android.util.xml.parse(is, xml.encoding.utf_8, xml2product); // 输出转换后的java对象 list<product> products = xml2product.getproducts(); string msg = "共" + products.size() + "个产品\n"; for (product product : products) { msg += "id:" + product.getid() + " 产品名:" + product.getname() + " 价格:" + product.getprice() + "\n"; } // 弹出对话框 new alertdialog.builder(this).settitle("产品信息").setmessage(msg) .setpositivebutton("关闭", null).show(); } catch (exception e) { } } }
效果图
code
activity_jar_zip.xml
<?xml version="1.0" encoding="utf-8"?> <linearlayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <button android:layout_width="fill_parent" android:layout_height="wrap_content" android:onclick="onclick_jar_compress" android:text="用jar格式压缩文件" /> <button android:layout_width="fill_parent" android:layout_height="wrap_content" android:onclick="onclick_jar_uncompress" android:text="解压jar格式文件" /> <button android:layout_width="fill_parent" android:layout_height="wrap_content" android:onclick="onclick_zip_compress" android:text="用zip格式压缩文件" /> <button android:layout_width="fill_parent" android:layout_height="wrap_content" android:onclick="onclick_zip_uncompress" android:text="解压zip格式文件" /> </linearlayout>
jarzipact
import android.os.bundle; import android.support.v7.app.appcompatactivity; import android.view.view; import android.widget.toast; import com.turing.base.r; import java.io.file; import java.io.fileinputstream; import java.io.fileoutputstream; import java.io.inputstream; import java.util.jar.jarentry; import java.util.jar.jarinputstream; import java.util.jar.jaroutputstream; import java.util.zip.zipentry; import java.util.zip.zipinputstream; import java.util.zip.zipoutputstream; public class jarzipact extends appcompatactivity { @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_jar_zip); } public void onclick_jar_compress(view view) { try { // 使用fileoutputstream对象指定一个要输出的压缩文件(file.jar) fileoutputstream fos = new fileoutputstream( android.os.environment.getexternalstoragedirectory() + "/file.jar"); // 第一步 创建jaroutputstream对象 jaroutputstream jos = new jaroutputstream(fos); // 第二步 创建一个jarentry对象,并指定待压缩文件在压缩包中的文件名 jarentry jarentry = new jarentry("strings.xml"); jos.putnextentry(jarentry); inputstream is = getresources().getassets().open("strings.xml"); byte[] buffer = new byte[8192]; int count = 0; // 第四步 写入数据 while ((count = is.read(buffer)) >= 0) { jos.write(buffer, 0, count); } // 第五步 关闭当前的jarentry等对象 is.close(); jos.closeentry(); jos.close(); toast.maketext(this, "成功将strings.xml文件以jar格式压缩.", toast.length_long) .show(); } catch (exception e) { toast.maketext(this, e.getmessage(), toast.length_long).show(); } } public void onclick_jar_uncompress(view view) { try { // 定义要解压的文件 string filename = android.os.environment .getexternalstoragedirectory() + "/file.jar"; if (!new file(filename).exists()) { toast.maketext(this, "压缩文件不存在.", toast.length_long).show(); return; } // 使用fileinputstream对象指定要解压的对象 fileinputstream fis = new fileinputstream(filename); // 1 创建jarinputstream对象来读取压缩文件(file.jar) jarinputstream jis = new jarinputstream(fis); // 2 调用getnextjarentry方法打开压缩包中的第一个文件 ,如果有多个,多次调用该方法 jarentry jarentry = jis.getnextjarentry(); // 3 输出已解压的文件 fileoutputstream fos = new fileoutputstream( android.os.environment.getexternalstoragedirectory() + "/" + jarentry.getname()); byte[] buffer = new byte[8192]; int count = 0; // 4 输出已解压的字节流 while ((count = jis.read(buffer)) >= 0) { fos.write(buffer, 0, count); } // 5 关闭 jis.closeentry(); jis.close(); fos.close(); toast.maketext(this, "成功解压jar格式的文件.", toast.length_long).show(); } catch (exception e) { toast.maketext(this, e.getmessage(), toast.length_long).show(); } } public void onclick_zip_compress(view view) { try { // 指定了2个待压缩的w文件,都在assets目录中 string[] filenames = new string[] {"main.xml", "strings.xml"}; fileoutputstream fos = new fileoutputstream( android.os.environment.getexternalstoragedirectory() + "/file.zip"); zipoutputstream zos = new zipoutputstream(fos); int i = 1; //枚举filenames中的所有待压缩文件 while (i <= filenames.length) { // 从filenames数组中取出当前待压缩的温佳明,作为压缩后的文件名,以保持要说前后文件名称一致 zipentry zipentry = new zipentry(filenames[i - 1]); // 打开当前的zipentry对象 zos.putnextentry(zipentry); inputstream is = getresources().getassets().open( filenames[i - 1]); byte[] buffer = new byte[8192]; int count = 0; // 写入数据 while ((count = is.read(buffer)) >= 0) { zos.write(buffer, 0, count); } zos.flush(); // 关闭当前的zipentry对象 zos.closeentry(); is.close(); i++; } zos.finish(); zos.close(); toast.maketext(this, "成功将main.xml、strings.xml文件以zip格式压缩.", toast.length_long).show(); } catch (exception e) { toast.maketext(this, e.getmessage(), toast.length_long).show(); } } public void onclick_zip_uncompress(view view) { try { // 指定待解压的文件 string filename = android.os.environment .getexternalstoragedirectory() + "/file.zip"; if (!new file(filename).exists()) { toast.maketext(this, "压缩文件不存在.", toast.length_long).show(); return; } fileinputstream fis = new fileinputstream(filename); zipinputstream zis = new zipinputstream(fis); zipentry zipentry = null; // 通过不断调用getnextentry方法来解压file.zip中所有的文件 while ((zipentry = zis.getnextentry()) != null) { fileoutputstream fos = new fileoutputstream( android.os.environment.getexternalstoragedirectory() + "/" + zipentry.getname()); byte[] buffer = new byte[8192]; int count = 0; while ((count = zis.read(buffer)) >= 0) { fos.write(buffer, 0, count); } zis.closeentry(); fos.close(); } zis.close(); toast.maketext(this, "成功解压jar格式的文件.", toast.length_long).show(); } catch (exception e) { toast.maketext(this, e.getmessage(), toast.length_long).show(); } } }
原文链接:http://blog.csdn.net/yangshangwei/article/details/50831269
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