OverView:
程序通过后台每天检查是否有最新版本,如果需要更新当前版本,将弹出对话框让用户选择是否在当前通过Market来更新
软件。
Knowledge Points:
- SharedPreferences: 一个轻量级的存储方法,类似于经常使用的.ini文件,它也是通过检索关键字来取得相应的数值。之所以是成为轻量级,是因为它所能应用的数值类型有限,对于存储较大数值,效率相对较低。官方参考
- System.currentTimeMillis:将当前时间以毫秒作为单位来表示,用于比较两个时间的先后顺序。(其数值表示从1970-01-01 00:00:00直到当前时间的总毫秒数)官方参考
- 通过网络来读取信息:在checkUpdate()方法中包含了通过制定的URL来读取网络资源。具体操作步骤,请参考源代码。
- Runnable: 在其内部的Run()方法中实现所要执行的任何代码,当这个runnable interface被调用后可以视作为新的线程。
Source Code:
- public class hello extends Activity {
- /** Called when the activity is first created. */
- private Handler mHandler;
-
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
-
- mHandler = new Handler();
-
- /* Get Last Update Time from Preferences */
- SharedPreferences prefs = getPreferences(0);
- long lastUpdateTime = prefs.getLong("lastUpdateTime", System.currentTimeMillis());
-
- int curVersion = 0;
- try {
- curVersion = getPackageManager().getPackageInfo("linhai.com.hello", 0).versionCode;
- } catch (NameNotFoundException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- Log.i("DEMO",String.valueOf(curVersion));
- /* Should Activity Check for Updates Now? */
- if ((lastUpdateTime + (24 * 60 * 60 * 1000)) < System.currentTimeMillis()) {
-
- /* Save current timestamp for next Check*/
- lastUpdateTime = System.currentTimeMillis();
- SharedPreferences.Editor editor = getPreferences(0).edit();
- editor.putLong("lastUpdateTime", lastUpdateTime);
- editor.commit();
-
- /* Start Update */
- // checkUpdate.start();
- }
- }
-
- /* This Thread checks for Updates in the Background */
- private Thread checkUpdate = new Thread()
- {
- public void run() {
- try {
- URL updateURL = new URL("http://my.company.com/update");
- URLConnection conn = updateURL.openConnection();
- InputStream is = conn.getInputStream();
- BufferedInputStream bis = new BufferedInputStream(is);
- ByteArrayBuffer baf = new ByteArrayBuffer(50);
-
- int current = 0;
- while((current = bis.read()) != -1){
- baf.append((byte)current);
- }
-
- /* Convert the Bytes read to a String. */
- final String s = new String(baf.toByteArray());
-
- /* Get current Version Number */
- int curVersion = getPackageManager().getPackageInfo("your.app.id", 0).versionCode;
- int newVersion = Integer.valueOf(s);
-
- /* Is a higher version than the current already out? */
- if (newVersion > curVersion) {
- /* Post a Handler for the UI to pick up and open the Dialog */
- mHandler.post(showUpdate);
- }
- } catch (Exception e) {
- }
- }
- };
-
- /* This Runnable creates a Dialog and asks the user to open the Market */
- private Runnable showUpdate = new Runnable(){
- public void run(){
- new AlertDialog.Builder(hello.this)
- .setIcon(R.drawable.ok)
- .setTitle("Update Available")
- .setMessage("An update for is available!\n\nOpen Android Market and see the details?")
- .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
- public void onClick(DialogInterface dialog, int whichButton) {
- /* User clicked OK so do some stuff */
- Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("market://search?q=pname:your.app.id"));
- startActivity(intent);
- }
- })
- .setNegativeButton("No", new DialogInterface.OnClickListener() {
- public void onClick(DialogInterface dialog, int whichButton) {
- /* User clicked Cancel */
- }
- })
- .show();
- }
- };
-
- }
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分为三个部分:
- 置于onCreate()方法中的程序用于判断当前时间是否需要检查更新(如果距离上次更新时间大于1天,将启动检查更新)
- 当以上条件满足时,启动checkUpdate来检查当前程序是否为最新版本。
- 如果确定版本已过期,那么将登录market,并直接指向当前程序页面。
*******************************************************************************************
向上言:
本人在
论坛曾经发过一关于此问题的
求助帖,虽然大至的思路和上文差不多,关键点是在于程序如何更新,现在看到它这里指出的更新方法居然是登录market。不过以后发布的程序都是在market中,问题就不存在。
- Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("market://search?q=pname:your.app.id"));
- startActivity(intent);
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大家都是在eclipse上
开发吧,在每次更新代码,
运行模拟器时,大家是否有注意到console的提示信息:
- [2009-06-06 19:53:50 - Hello] Android Launch!
- [2009-06-06 19:53:50 - Hello] adb is running normally.
- [2009-06-06 19:53:50 - Hello] Performing linhai.com.hello.hello activity launch
- [2009-06-06 19:53:50 - Hello] Automatic Target Mode: using existing emulator 'emulator-5554' running compatible AVD 'avd'
- [2009-06-06 19:53:50 - Hello] WARNING: Application does not specify an API level requirement!
- [2009-06-06 19:53:50 - Hello] Device API version is 3 (Android 1.5)
- [2009-06-06 19:53:50 - Hello] Uploading Hello.apk onto device 'emulator-5554'
- [2009-06-06 19:53:50 - Hello] Installing Hello.apk...
- [2009-06-06 19:54:05 - Hello] Application already exists. Attempting to re-install instead...
- [2009-06-06 19:54:31 - Hello] Success!
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分析:
1。
android正常运行
2。通过配置文件AndroidManifest.xml中运行我们的程序
3。
Uploading Hello.apk onto device 'emulator-5554'这句是关键,更新我们的程序
4。
Installing Hello.apk...
5。
Application already exists. Attempting to re-install instead...//程序已经存在,尝试重新安装
所以如果我们的程序要
自动更新,本人初步猜想是和上面的步骤是一样的。
详看logcat中的log
- 06-06 11:54:02.567: DEBUG/PackageParser(582): Scanning package: /data/app/vmdl12464.tmp
- 06-06 11:54:08.048: INFO/PackageManager(582): Removing non-system package:linhai.com.hello
- 06-06 11:54:08.187: DEBUG/PackageManager(582): Removing package linhai.com.hello
- 06-06 11:54:08.286: DEBUG/PackageManager(582): Activities: linhai.com.hello.hello
- 06-06 11:54:11.136: DEBUG/PackageManager(582): Scanning package linhai.com.hello
- 06-06 11:54:11.301: INFO/PackageManager(582): /data/app/vmdl12464.tmp changed; unpacking
- 06-06 11:54:11.626: DEBUG/installd(555): DexInv: --- BEGIN '/data/app/vmdl12464.tmp' ---
- 06-06 11:54:12.987: DEBUG/dalvikvm(7756): DexOpt: load 224ms, verify 265ms, opt 1ms
- 06-06 11:54:13.047: DEBUG/installd(555): DexInv: --- END '/data/app/vmdl12464.tmp' (success) ---
- 06-06 11:54:13.057: DEBUG/PackageManager(582): Activities: linhai.com.hello.hello
- 06-06 11:54:15.608: INFO/installd(555): move
/data/dalvik-cache/data@app@vmdl12464.tmp@classes.dex ->
/data/dalvik-cache/data@app@linhai.com.hello.apk@classes.dex
- 06-06 11:54:15.737: DEBUG/PackageManager(582): New package installed in /data/app/linhai.com.hello.apk
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关于此类的自动更新的第三方管理软件已经有了叫
aTrackDog,其原理就是使用上面的方式。
关于得到版本号,使用:
- int curVersion = getPackageManager().getPackageInfo("your.app.id", 0).versionCode;
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程序版本号的是放在AndroidManifest.xml文件中:
- <manifest xmlns:android="http://schemas.android.com/apk/res/android"
- package="linhai.com.hello" android:versionCode="2" android:versionName="2.0.1">
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主点是关于:getPackageManager()在这个下面有很多方法,你可以通过它得,得到当前终端安装的程序等。关于安装包的函数是:getPackageManager().installPackage(packageURI)
动手试验:
在dos状态下运行:
查看logcat下的信息,大致和刚才相同,分析流程:
- 06-06 12:18:58.827: INFO/jdwp(8368): received file descriptor 20 from ADB
- 06-06 12:19:02.546: DEBUG/PackageParser(582): Scanning package: /data/app/vmdl12465.tmp
- 06-06 12:19:07.738: INFO/PackageManager(582): /data/app/vmdl12465.tmp changed; unpacking
- 06-06 12:19:07.978: DEBUG/installd(555): DexInv: --- BEGIN '/data/app/vmdl12465.tmp' ---
- 06-06 12:19:09.617: DEBUG/dalvikvm(8378): DexOpt: load 254ms, verify 564ms, opt 3ms
- 06-06 12:19:09.697: DEBUG/installd(555): DexInv: --- END '/data/app/vmdl12465.tmp' (success) ---
- 06-06 12:19:11.907: INFO/installd(555): move
/data/dalvik-cache/data@app@vmdl12465.tmp@classes.dex ->
/data/dalvik-cache/data@app@com.example.android.snake.apk@classes.dex
- 06-06 12:19:11.956: DEBUG/PackageManager(582): New package installed in /data/app/com.example.android.snake.apk
- 06-06 12:19:14.746: DEBUG/dalvikvm(8368): VM cleaning up
- 06-06 12:19:14.857: DEBUG/dalvikvm(8368): LinearAlloc 0x0 used 628420 of 4194304 (14%)
- 06-06 12:19:15.897: DEBUG/dalvikvm(582): GC freed 17704 objects / 903984 bytes in 615ms
- 06-06 12:19:15.936: DEBUG/HomeLoaders(625): application intent received: android.intent.action.PACKAGE_ADDED, replacing=false
- 06-06 12:19:15.936: DEBUG/HomeLoaders(625): --> package:com.example.android.snake
- 06-06 12:19:15.936: DEBUG/HomeLoaders(625): --> add package
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1。接收
数据,保存到临时文件中/data/app/vmdl12465.tmp
2。解压此文件,注意路径/data/dalvik-cache/data@
app@vmdl12465.tmp@classes.dex
它是在data下的dalvik-cache下
3.安装文件[这个步骤还包括查找程序是否已经安装等]
4.使用GC清理内存
查看DDMS中的结构
看到此文件结构,应该可以想起linux下的文件
系统和它的权限管理,也就可以理解,为什么我们的程序无法在data下创建文件之类的问题了。
转载:
http://www.androidres.com/?p=349