为程序添加版本自动更新功能(转+详细分析)-优快云博客

本文介绍了一种Android应用自动更新的实现方式，包括利用SharedPreferences记录更新时间、通过网络检查新版本以及通过Market引导用户更新等内容。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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();
}
};
}

复制代码

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);

复制代码

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!

复制代码

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

复制代码

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：