获取android应用的版本号

一、获取应用的版本号

怎样获取当前的应用版本号呢，我们经常看到在设置——应用管理管理，点击某一个应用，会看到应用名称下面version 1.0等版本号字样，那怎样获取这个应用版本呢

	/**
	 * 获取当前的应用版本号
	 * 
	 * @return 返回版本号
	 */
	private String getVersionName() {
		try {
			PackageManager packageManager = getPackageManager();
			PackageInfo packInfo = packageManager.getPackageInfo(
					getPackageName(), 0);
			String version = packInfo.versionName;
			return version;
		} catch (NameNotFoundException e) {
			e.printStackTrace();
		}
		return null;
	}

如AndroidManifest.xml中版本号为2.3.4

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.lin.test"
    android:versionCode="14"
    android:versionName="2.3.4" >

上面方法将返回2.3.4

如果想获取android:versionCode的值，那应该怎样获取呢

int versionCode =packInfo.versionCode;

二、获取android系统的版本号

上面可以获取应用的版本号了，但是你想一下，你的应用只能在android sdk2.0或android sdk 2.3以上的版本号才可以运行，那是不是要获取android系统的版本号，判断一下是不是在规定的版本号以上？

那现在应该怎样获取android版本号呢

android.os.Build.VERSION.SDK      //sdk的字符串值 ,也可以用数值：android.os.Build.VERSION.SDK_INT

android.os.Build.VERSION.RELEASE //sdk对应的版本号

如 android.os.Build.VERSION.SDK为10，对应的android.os.Build.VERSION.RELEASE版本号为2.3.x

如果要在android 2.3版本上才可以使用，应判断下一

if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1){
//这个是符合的February 2011: Android 2.3.3.
}

下面是VERSION_CODES类源码

public static class VERSION_CODES {
        /**
         * Magic version number for a current development build, which has
         * not yet turned into an official release.
         */
        public static final int CUR_DEVELOPMENT = 10000;
        
        /**
         * October 2008: The original, first, version of Android.  Yay!
         */
        public static final int BASE = 1;
        
        /**
         * February 2009: First Android update, officially called 1.1.
         */
        public static final int BASE_1_1 = 2;
        
        /**
         * May 2009: Android 1.5.
         */
        public static final int CUPCAKE = 3;
        
        /**
         * September 2009: Android 1.6.
         * 
         * <p>Applications targeting this or a later release will get these
         * new changes in behavior:</p>
         * <ul>
         * <li> They must explicitly request the
         * {@link android.Manifest.permission#WRITE_EXTERNAL_STORAGE} permission to be
         * able to modify the contents of the SD card.  (Apps targeting
         * earlier versions will always request the permission.)
         * <li> They must explicitly request the
         * {@link android.Manifest.permission#READ_PHONE_STATE} permission to be
         * able to be able to retrieve phone state info.  (Apps targeting
         * earlier versions will always request the permission.)
         * <li> They are assumed to support different screen densities and
         * sizes.  (Apps targeting earlier versions are assumed to only support
         * medium density normal size screens unless otherwise indicated).
         * They can still explicitly specify screen support either way with the
         * supports-screens manifest tag.
         * </ul>
         */
        public static final int DONUT = 4;
        
        /**
         * November 2009: Android 2.0
         * 
         * <p>Applications targeting this or a later release will get these
         * new changes in behavior:</p>
         * <ul>
         * <li> The {@link android.app.Service#onStartCommand
         * Service.onStartCommand} function will return the new
         * {@link android.app.Service#START_STICKY} behavior instead of the
         * old compatibility {@link android.app.Service#START_STICKY_COMPATIBILITY}.
         * <li> The {@link android.app.Activity} class will now execute back
         * key presses on the key up instead of key down, to be able to detect
         * canceled presses from virtual keys.
         * <li> The {@link android.widget.TabWidget} class will use a new color scheme
         * for tabs. In the new scheme, the foreground tab has a medium gray background
         * the background tabs have a dark gray background.
         * </ul>
         */
        public static final int ECLAIR = 5;
        
        /**
         * December 2009: Android 2.0.1
         */
        public static final int ECLAIR_0_1 = 6;
        
        /**
         * January 2010: Android 2.1
         */
        public static final int ECLAIR_MR1 = 7;
        
        /**
         * June 2010: Android 2.2
         */
        public static final int FROYO = 8;
        
        /**
         * November 2010: Android 2.3
         */
        public static final int GINGERBREAD = 9;
        
        /**
         * February 2011: Android 2.3.3.
         */
        public static final int GINGERBREAD_MR1 = 10;

        /**
         * February 2011: Android 3.0.
         *
         * <p>Applications targeting this or a later release will get these
         * new changes in behavior:</p>
         * <ul>
         * <li> The default theme for applications is now dark holographic:
         *      {@link android.R.style#Theme_Holo}.
         * <li> The activity lifecycle has changed slightly as per
         * {@link android.app.Activity}.
         * <li> When an application requires a permission to access one of
         * its components (activity, receiver, service, provider), this
         * permission is no longer enforced when the application wants to
         * access its own component.  This means it can require a permission
         * on a component that it does not itself hold and still access that
         * component.
         * </ul>
         */
        public static final int HONEYCOMB = 11;
        
        /**
         * May 2011: Android 3.1.
         */
        public static final int HONEYCOMB_MR1 = 12;
        
        /**
         * June 2011: Android 3.2.
         *
         * <p>Update to Honeycomb MR1 to support 7 inch tablets, improve
         * screen compatibility mode, etc.</p>
         *
         * <p>As of this version, applications that don't say whether they
         * support XLARGE screens will be assumed to do so only if they target
         * {@link #HONEYCOMB} or later; it had been {@link #GINGERBREAD} or
         * later.  Applications that don't support a screen size at least as
         * large as the current screen will provide the user with a UI to
         * switch them in to screen size compatibility mode.</p>
         *
         * <p>This version introduces new screen size resource qualifiers
         * based on the screen size in dp: see
         * {@link android.content.res.Configuration#screenWidthDp},
         * {@link android.content.res.Configuration#screenHeightDp}, and
         * {@link android.content.res.Configuration#smallestScreenWidthDp}.
         * Supplying these in <supports-screens> as per
         * {@link android.content.pm.ApplicationInfo#requiresSmallestWidthDp},
         * {@link android.content.pm.ApplicationInfo#compatibleWidthLimitDp}, and
         * {@link android.content.pm.ApplicationInfo#largestWidthLimitDp} is
         * preferred over the older screen size buckets and for older devices
         * the appropriate buckets will be inferred from them.</p>
         *
         * <p>New {@link android.content.pm.PackageManager#FEATURE_SCREEN_PORTRAIT}
         * and {@link android.content.pm.PackageManager#FEATURE_SCREEN_LANDSCAPE}
         * features are introduced in this release.  Applications that target
         * previous platform versions are assumed to require both portrait and
         * landscape support in the device; when targeting Honeycomb MR1 or
         * greater the application is responsible for specifying any specific
         * orientation it requires.</p>
         */
        public static final int HONEYCOMB_MR2 = 13;

        /**
         * Android 4.0.
         *
         * <p>Applications targeting this or a later release will get these
         * new changes in behavior:</p>
         * <ul>
         * <li> For devices without a dedicated menu key, the software compatibility
         * menu key will not be shown even on phones.  By targeting Ice Cream Sandwich
         * or later, your UI must always have its own menu UI affordance if needed,
         * on both tablets and phones.  The ActionBar will take care of this for you.
         * <li> 2d drawing hardware acceleration is now turned on by default.
         * You can use
         * {@link android.R.attr#hardwareAccelerated android:hardwareAccelerated}
         * to turn it off if needed, although this is strongly discouraged since
         * it will result in poor performance on larger screen devices.
         * <li> The default theme for applications is now the "device default" theme:
         *      {@link android.R.style#Theme_DeviceDefault}. This may be the
         *      holo dark theme or a different dark theme defined by the specific device.
         *      The {@link android.R.style#Theme_Holo} family must not be modified
         *      for a device to be considered compatible. Applications that explicitly
         *      request a theme from the Holo family will be guaranteed that these themes
         *      will not change character within the same platform version. Applications
         *      that wish to blend in with the device should use a theme from the
         *      {@link android.R.style#Theme_DeviceDefault} family.
         * <li> Managed cursors can now throw an exception if you directly close
         * the cursor yourself without stopping the management of it; previously failures
         * would be silently ignored.
         * <li> The fadingEdge attribute on views will be ignored (fading edges is no
         * longer a standard part of the UI).  A new requiresFadingEdge attribute allows
         * applications to still force fading edges on for special cases.
         * </ul>
         */
        public static final int ICE_CREAM_SANDWICH = 14;
    }