PendingIntent.send()方法启动Activity和startActivity的区别

Question

监听home键广播启动Activity会延迟5s，但是通过PendingIntent.send()方法启动Activity可以立即启动?查看源码只追到Activity启动会延迟5秒的原因，未追查到PendingIntent
.send()可以立即启动Activity的原因，不知是否有小伙伴解决过这个问题。

private BroadcastReceiver homeKeyReceiver = new BroadcastReceiver() {
        private static final String SYSTEM_DIALOG_REASON_KEY = "reason";
        private static final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";

        @Override
        public void onReceive(Context context, Intent intent) {
            if (TextUtils.equals(intent.getAction(), Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {

                if (TextUtils.equals(intent.getStringExtra(SYSTEM_DIALOG_REASON_KEY), SYSTEM_DIALOG_REASON_HOME_KEY)) {

                    Intent secondIntent = new Intent(FirstMainActivity.this, SecondMainActivity.class);
                    secondIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_NO_ANIMATION
                            | Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
                    PendingIntent pendingIntent = PendingIntent.getActivity(FirstMainActivity.this, 0,
                            secondIntent, 0);
                    try {
                        pendingIntent.send();
                    } catch (PendingIntent.CanceledException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    };

如果在onReceive方法通过startActivity启动SecondMainActivity，会延时5秒启动。
麻烦告知一下PendingIntent.send()为何能够绕过这个延时5秒的限制，特别感谢。

Answer 1

PendingIntent的方式 会使下面这个判断返回true 所以能绕过
14108 perm = checkComponentPermission(STOP_APP_SWITCHES, callingPid, callingUid, -1, true);
14109 if (perm == PackageManager.PERMISSION_GRANTED) {
14110 return true;
14111 }