另一种过滤系统应用程序的方法(适用于king9981的例子):

/**
 * Return whether the given PackageInfo represents a system package or not.
 * User-installed packages (Market or otherwise) should not be denoted as
 * system packages.
 * 
 * @param pkgInfo
 * @return
 */
private boolean isSystemPackage(PackageInfo pkgInfo) {
    return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0);
}

下面是使用PackageManager的一种更简洁的方式

final PackageManager pm = getPackageManager();
//get a list of installed apps.
List<ApplicationInfo> packages = pm.getInstalledApplications(PackageManager.GET_META_DATA);

for (ApplicationInfo packageInfo : packages) {
    Log.d(TAG, "Installed package :" + packageInfo.packageName);
    Log.d(TAG, "Source dir : " + packageInfo.sourceDir);
    Log.d(TAG, "Launch Activity :" + pm.getLaunchIntentForPackage(packageInfo.packageName)); 
}
// the getLaunchIntentForPackage returns an intent that you can use with startActivity() 

更多信息请点击这里http://qtcstation.com/2011/02/how-to-launch-another-app-from-your-app/

要获得所有已安装的应用程序，您可以使用包管理器

List<PackageInfo> apps = getPackageManager().getInstalledPackages(0);

要运行一个应用程序，你可以使用它的包名

Intent launchApp = getPackageManager().getLaunchIntentForPackage(“package name”)
startActivity(launchApp);

欲了解更多细节，请阅读这个博客http://codebucket.co.in/android-get-list-of-all-installed-apps/

private static boolean isThisASystemPackage(Context context, PackageInfo  packageInfo ) {
        try {
            PackageInfo sys = context.getPackageManager().getPackageInfo("android", PackageManager.GET_SIGNATURES);
            return (packageInfo != null && packageInfo.signatures != null &&
                    sys.signatures[0].equals(packageInfo.signatures[0]));
        } catch (NameNotFoundException e) {
            return false;
        }
    }

另一种过滤系统应用程序的方法(适用于king9981的例子):

/**
 * Return whether the given PackageInfo represents a system package or not.
 * User-installed packages (Market or otherwise) should not be denoted as
 * system packages.
 * 
 * @param pkgInfo
 * @return
 */
private boolean isSystemPackage(PackageInfo pkgInfo) {
    return ((pkgInfo.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0);
}

这里有一个很好的例子:

class PInfo {
    private String appname = "";
    private String pname = "";
    private String versionName = "";
    private int versionCode = 0;
    private Drawable icon;
    private void prettyPrint() {
        Log.v(appname + "\t" + pname + "\t" + versionName + "\t" + versionCode);
    }
}

private ArrayList<PInfo> getPackages() {
    ArrayList<PInfo> apps = getInstalledApps(false); /* false = no system packages */
    final int max = apps.size();
    for (int i=0; i<max; i++) {
        apps.get(i).prettyPrint();
    }
    return apps;
}

private ArrayList<PInfo> getInstalledApps(boolean getSysPackages) {
    ArrayList<PInfo> res = new ArrayList<PInfo>();        
    List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);
    for(int i=0;i<packs.size();i++) {
        PackageInfo p = packs.get(i);
        if ((!getSysPackages) && (p.versionName == null)) {
            continue ;
        }
        PInfo newInfo = new PInfo();
        newInfo.appname = p.applicationInfo.loadLabel(getPackageManager()).toString();
        newInfo.pname = p.packageName;
        newInfo.versionName = p.versionName;
        newInfo.versionCode = p.versionCode;
        newInfo.icon = p.applicationInfo.loadIcon(getPackageManager());
        res.add(newInfo);
    }
    return res; 
}