Android判断应用是否已经安装

/**
* 判断应用是否已安装
*
* @param context
* @param packageName
* @return
*/
private boolean isInstalled(Context context, String packageName) {
boolean hasInstalled = false;
PackageManager pm = context.getPackageManager();
List<PackageInfo> list = pm
.getInstalledPackages(PackageManager.PERMISSION_GRANTED);
for (PackageInfo p : list) {
if (packageName != null && packageName.equals(p.packageName)) {
hasInstalled = true;
break;
}
}
return hasInstalled;
}