ShareSDK社会化分享判断是否安装微信、QQ等客户端

问题由来：

/**
* 判断是否安装了微博
* @param context
* @return
*/
public static boolean isWeiboInstalled(Context context) {
final PackageManager packageManager = context.getPackageManager();
List<PackageInfo> pinfo = packageManager.getInstalledPackages(0);
if (pinfo != null) {
for (int i = 0; i < pinfo.size(); i++) {
String pn = pinfo.get(i).packageName.toLowerCase(Locale.ENGLISH);
if (pn.equals("com.sina.weibo")) {
return true;
}
}
}
return false;
}

/**
* 判断是否安装了微信
* @param context
* @return
*/
public static boolean isWeixinInstalled(Context context) {
final PackageManager packageManager = context.getPackageManager();
// 获取所有已安装程序的包信息
List<PackageInfo> pinfo = packageManager.getInstalledPackages(0);
if (pinfo != null) {
for (int i = 0; i < pinfo.size(); i++) {
String pn = pinfo.get(i).packageName.toLowerCase(Locale.ENGLISH);
if (pn.equals("com.tencent.mm")) {
return true;
}
}
}
return false;
}

/**
* 判断是否安装了QQ
* @param context
* @return
*/
public static boolean isQQClientInstalled(Context context) {
final PackageManager packageManager = context.getPackageManager();
List<PackageInfo> pinfo = packageManager.getInstalledPackages(0);
if (pinfo != null) {
for (int i = 0; i < pinfo.size(); i++) {
String pn = pinfo.get(i).packageName.toLowerCase(Locale.ENGLISH);
if (pn.equals("com.tencent.mobileqq")) {
return true;
}
}
}
return false;
}