需要注意的是，iOS9以上的系統需要在info.plist添加白名單

    <key>LSApplicationQueriesSchemes</key>
    <array>
        <string>wechat</string>
        <string>weixin</string>
        <string>alipay</string>
        <string>alipayshare</string>
        <string>mqq</string>
    </array>

    if([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"mqq://"]])
    {
        NSString *QQ = @"1099779883";
        //調用QQ客戶端,發起QQ臨時會話
        NSString *url = [NSString stringWithFormat:@"mqq://im/chat?chat_type=wpa&uin=%@&version=1&src_type=web",QQ];
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];
    }
    else{
        UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"溫馨提示" message:@"手機未安裝QQ" delegate:self cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
        [alert show];
    }