使用密码保护应用程序

Question

I've got an Application (extends), and it runs some service in the background to monitor beacons. Checking if you're in or out of range and then preform some actions.

I only got one Activity in my Application and that is the Settings Activity. The service automatically starts after boot, and runs indefinitely. When a person tries to open the app, the SettingsActivity should not become available unless a correct password gets provided.

So in the onPause() and onResume() I'd like to launch a Dialog that asks for a password. When a correct password gets entered (Retrofit checks this and returns a boolean), he is allowed to the SettingsActivity.

Problem: How do I make my activity invisible onPause() and how do I make it visible again after correct password (launch dialog in onResume()).

I could think of one solution and that is adding another View to my settings_view.xml, let it fill the parent and set it VISIBILITY.GONE after right password and VISIBILITY.VISIBLE @ onPause(). I want to do this in onPause() because then the person cannot "see" anything when going to the recent app screen. But this seems an extremely sloppy solution.

Is there anyway I can just blackout/tint the layout in onPause() and remove the blackout/tint after the right password is entered?

Thanks for the advice :)

Answer 1

Problem: How do I make my activity invisible onPause() and how do I make it visible again after correct password (launch dialog in onResume()).

You should consider the rest of your activity lifecycle for this. If you are getting some info from the internet, then lots of problems may take time in your application. You may have bad signal, no network available, or even the network connection adapter is off.

Consider this instead: Activity "login" onCreate : Create a bland activity with the required files, and then a submit button. Once submitted, query the network status and whatever you are using for login. Then save the result for a while (lets say a day, or 30 minutes, whatever feels best for your application), usually a SharedPreferences will do.

Activity "SettingsActivity" onResume : check if saved data allows user to see the Activity. If it doesnt, finish the activity, and start a "login" one.

Answer 2

I solved this question as follows:

I included a layout:

File activity_settings.xml

<include layout="@layout/view_authentication"
    android:id="@+id/authenticationView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

File view_authentication.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/authenticationView"
            android:clipToPadding="false">

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:padding="10dp">

    <EditText
        android:id="@+id/authentication_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:hint="Password"
        android:password="true"/>

    <Button
        android:id="@+id/authentication_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:text="@string/authentication_button"/>

</LinearLayout>
</RelativeLayout>

In my SettingsActivity.java I added following line in onCreate(). This prevents screenshots being taken and blocks seeing anything in recent apps

    getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);

In onResume(), which gets called before opening the app for the first time, or re-opening it. I call following method:

public void showAuthenticationFrame() {
    authenticationView.setVisibility(View.VISIBLE);
    contentFrame.setVisibility(View.GONE);
}

When the correct password is entered, I do the opposite, I set authenticationView to GONE and contentFrame to VISIBLE.