Android编程判断手机上是否安装了某个程序的方法

private boolean isPkgInstalled(String pkgName) {
PackageInfo packageInfo = null;
try {
  packageInfo = this.getPackageManager().getPackageInfo(pkgName, 0);
} catch (NameNotFoundException e) {
  packageInfo = null;
  e.printStackTrace();
}
if (packageInfo == null) {
  return false;
} else {
  return true;
}