Don't show tap protection dialog until it's needed.

briar-android/src/main/java/org/briarproject/briar/android/ScreenFilterMonitorImpl.java

@@ -183,15 +183,13 @@ public class ScreenFilterMonitorImpl extends BroadcastReceiver
 
 	@Override
 	@UiThread
-	public void storeAppsAsShown(Collection<String> s, boolean persistent) {
-		HashSet<String> buf = new HashSet<>(s);
-		shownApps.addAll(buf);
-		if (persistent && !s.isEmpty()) {
-			buf.addAll(getShownScreenFilterApps());
-			prefs.edit()
-					.putStringSet(PREF_SCREEN_FILTER_APPS, buf)
-					.apply();
-		}
+	public void storeAppsAsShown(Collection<String> shown) {
+		shownApps.addAll(shown);
+		HashSet<String> buf = new HashSet<>(shown);
+		buf.addAll(getShownScreenFilterApps());
+		prefs.edit()
+				.putStringSet(PREF_SCREEN_FILTER_APPS, buf)
+				.apply();
 	}
 
 	private Set<String> getInstalledScreenFilterApps() {

briar-android/src/main/java/org/briarproject/briar/android/StartupFailureActivity.java

@@ -27,7 +27,7 @@ public class StartupFailureActivity extends BaseActivity {
 	}
 
 	@Override
-	protected void showNewScreenFilterWarning() {
+	protected void showScreenFilterWarning() {
 		// Don't show here, service might not be available
 	}
 

briar-android/src/main/java/org/briarproject/briar/android/activity/BaseActivity.java

@@ -2,9 +2,13 @@ package org.briarproject.briar.android.activity;
 
 import android.os.Bundle;
 import android.os.IBinder;
+import android.support.annotation.LayoutRes;
 import android.support.annotation.UiThread;
 import android.support.v7.app.AppCompatActivity;
+import android.support.v7.widget.Toolbar;
 import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewGroup.LayoutParams;
 import android.view.inputmethod.InputMethodManager;
 
 import org.briarproject.bramble.api.db.DbException;
@@ -13,7 +17,9 @@ import org.briarproject.briar.android.BriarApplication;
 import org.briarproject.briar.android.DestroyableContext;
 import org.briarproject.briar.android.controller.ActivityLifecycleController;
 import org.briarproject.briar.android.forum.ForumModule;
-import org.briarproject.briar.android.fragment.SFDialogFragment;
+import org.briarproject.briar.android.fragment.ScreenFilterDialogFragment;
+import org.briarproject.briar.android.widget.TapSafeFrameLayout;
+import org.briarproject.briar.android.widget.TapSafeFrameLayout.OnTapFilteredListener;
 import org.briarproject.briar.api.android.ScreenFilterMonitor;
 
 import java.util.ArrayList;
@@ -23,21 +29,23 @@ import java.util.Set;
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
 import static android.view.WindowManager.LayoutParams.FLAG_SECURE;
 import static android.view.inputmethod.InputMethodManager.SHOW_IMPLICIT;
 import static org.briarproject.briar.android.TestingConstants.PREVENT_SCREENSHOTS;
 
 public abstract class BaseActivity extends AppCompatActivity
-		implements DestroyableContext {
+		implements DestroyableContext, OnTapFilteredListener {
+
+	@Inject
+	protected ScreenFilterMonitor screenFilterMonitor;
+
 	protected ActivityComponent activityComponent;
 
 	private final List<ActivityLifecycleController> lifecycleControllers =
 			new ArrayList<>();
 	private boolean destroyed = false;
-
-	@Inject
-	protected ScreenFilterMonitor screenFilterMonitor;
-	private SFDialogFragment dialogFrag;
+	private ScreenFilterDialogFragment dialogFrag;
 
 	public abstract void injectActivity(ActivityComponent component);
 
@@ -65,7 +73,6 @@ public abstract class BaseActivity extends AppCompatActivity
 		for (ActivityLifecycleController alc : lifecycleControllers) {
 			alc.onActivityCreate(this);
 		}
-
 	}
 
 	public ActivityComponent getActivityComponent() {
@@ -97,12 +104,6 @@ public abstract class BaseActivity extends AppCompatActivity
 		}
 	}
 
-	@Override
-	protected void onPostResume() {
-		super.onPostResume();
-		showNewScreenFilterWarning();
-	}
-
 	@Override
 	protected void onPause() {
 		super.onPause();
@@ -112,18 +113,18 @@ public abstract class BaseActivity extends AppCompatActivity
 		}
 	}
 
-	protected void showNewScreenFilterWarning() {
-		final Set<String> apps = screenFilterMonitor.getApps();
-		if (apps.isEmpty()) {
-			return;
-		}
-		dialogFrag = SFDialogFragment.newInstance(new ArrayList<>(apps));
+	protected void showScreenFilterWarning() {
+		if (dialogFrag != null && dialogFrag.isVisible()) return;
+		Set<String> apps = screenFilterMonitor.getApps();
+		if (apps.isEmpty()) return;
+		dialogFrag =
+				ScreenFilterDialogFragment.newInstance(new ArrayList<>(apps));
 		dialogFrag.setCancelable(false);
-		dialogFrag.show(getSupportFragmentManager(), "SFDialog");
+		dialogFrag.show(getSupportFragmentManager(), dialogFrag.getTag());
 	}
 
-	public void rememberShownApps(ArrayList<String> s, boolean permanent) {
-		screenFilterMonitor.storeAppsAsShown(s, permanent);
+	public void rememberShownApps(ArrayList<String> s) {
+		screenFilterMonitor.storeAppsAsShown(s);
 	}
 
 	@Override
@@ -161,4 +162,70 @@ public abstract class BaseActivity extends AppCompatActivity
 		supportFinishAfterTransition();
 	}
 
+	/*
+	 * Wraps the given view in a wrapper that notifies this activity when an
+	 * obscured touch has been filtered, and returns the wrapper.
+	 */
+	private View makeTapSafeWrapper(View v) {
+		TapSafeFrameLayout wrapper = new TapSafeFrameLayout(this);
+		wrapper.setLayoutParams(new LayoutParams(MATCH_PARENT, MATCH_PARENT));
+		wrapper.setOnTapFilteredListener(this);
+		wrapper.addView(v);
+		return wrapper;
+	}
+
+	/*
+	 * Finds the AppCompat toolbar, if any, and configures it to filter
+	 * obscured touches. If a custom toolbar is used, it will be part of the
+	 * content view and thus protected by the wrapper. But the default toolbar
+	 * is outside the wrapper.
+	 */
+	private void protectToolbar() {
+		View decorView = getWindow().getDecorView();
+		if (decorView instanceof ViewGroup) {
+			Toolbar toolbar = findToolbar((ViewGroup) decorView);
+			if (toolbar != null) toolbar.setFilterTouchesWhenObscured(true);
+		}
+	}
+
+	@Nullable
+	private Toolbar findToolbar(ViewGroup vg) {
+		for (int i = 0, len = vg.getChildCount(); i < len; i++) {
+			View child = vg.getChildAt(i);
+			if (child instanceof Toolbar) return (Toolbar) child;
+			if (child instanceof ViewGroup) {
+				Toolbar toolbar = findToolbar((ViewGroup) child);
+				if (toolbar != null) return toolbar;
+			}
+		}
+		return null;
+	}
+
+	@Override
+	public void setContentView(@LayoutRes int layoutRes) {
+		setContentView(getLayoutInflater().inflate(layoutRes, null));
+	}
+
+	@Override
+	public void setContentView(View v) {
+		super.setContentView(makeTapSafeWrapper(v));
+		protectToolbar();
+	}
+
+	@Override
+	public void setContentView(View v, LayoutParams layoutParams) {
+		super.setContentView(makeTapSafeWrapper(v), layoutParams);
+		protectToolbar();
+	}
+
+	@Override
+	public void addContentView(View v, LayoutParams layoutParams) {
+		super.addContentView(makeTapSafeWrapper(v), layoutParams);
+		protectToolbar();
+	}
+
+	@Override
+	public void onTapFiltered() {
+		showScreenFilterWarning();
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/fragment/ScreenFilterDialogFragment.java

@@ -22,10 +22,11 @@ import javax.annotation.Nullable;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-public class SFDialogFragment extends DialogFragment {
+public class ScreenFilterDialogFragment extends DialogFragment {
 
-	public static SFDialogFragment newInstance(ArrayList<String> apps) {
-		SFDialogFragment frag = new SFDialogFragment();
+	public static ScreenFilterDialogFragment newInstance(
+			ArrayList<String> apps) {
+		ScreenFilterDialogFragment frag = new ScreenFilterDialogFragment();
 		Bundle args = new Bundle();
 		args.putStringArrayList("apps", apps);
 		frag.setArguments(args);
@@ -34,31 +35,25 @@ public class SFDialogFragment extends DialogFragment {
 
 	@Override
 	public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
-		AlertDialog.Builder builder =
-				new AlertDialog.Builder(
-						getActivity(),
-						R.style.BriarDialogThemeNoFilter);
+		AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(),
+				R.style.BriarDialogThemeNoFilter);
 		builder.setTitle(R.string.screen_filter_title);
 		LayoutInflater li = getActivity().getLayoutInflater();
-		//Pass null here because it's an AlertDialog
-		View v =
-				li.inflate(R.layout.alert_dialog_checkbox, null,
-						false);
+		// Pass null here because it's an AlertDialog
+		View v = li.inflate(R.layout.alert_dialog_checkbox, null, false);
 		TextView t = (TextView) v.findViewById(R.id.alert_dialog_text);
 		final ArrayList<String> apps =
 				getArguments().getStringArrayList("apps");
 		t.setText(getString(R.string.screen_filter_body, TextUtils
 				.join("\n", apps)));
-		final CheckBox cb =
-				(CheckBox) v.findViewById(
-						R.id.checkBox_screen_filter_reminder);
+		final CheckBox cb = (CheckBox) v.findViewById(
+				R.id.checkbox_dont_show_again);
 		builder.setNeutralButton(R.string.continue_button,
 				new DialogInterface.OnClickListener() {
 					@Override
-					public void onClick(DialogInterface dialog,
-							int which) {
-						((BaseActivity) getActivity())
-								.rememberShownApps(apps, cb.isChecked());
+					public void onClick(DialogInterface dialog, int which) {
+						if (cb.isChecked())
+						((BaseActivity) getActivity()).rememberShownApps(apps);
 					}
 				});
 		builder.setView(v);

briar-android/src/main/java/org/briarproject/briar/android/splash/SplashScreenActivity.java

@@ -84,7 +84,8 @@ public class SplashScreenActivity extends BaseActivity {
 	}
 
 	@Override
-	protected void showNewScreenFilterWarning() {
+	protected void showScreenFilterWarning() {
+		// Ignore touches until the next activity is shown
 	}
 
 	private void enableStrictMode() {

briar-android/src/main/java/org/briarproject/briar/android/widget/TapSafeFrameLayout.java

@@ -0,0 +1,51 @@
+package org.briarproject.briar.android.widget;
+
+import android.content.Context;
+import android.support.annotation.AttrRes;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.widget.FrameLayout;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.Nullable;
+
+import static android.view.MotionEvent.FLAG_WINDOW_IS_OBSCURED;
+
+@NotNullByDefault
+public class TapSafeFrameLayout extends FrameLayout {
+
+	@Nullable
+	private OnTapFilteredListener listener;
+
+	public TapSafeFrameLayout(Context context) {
+		super(context);
+		setFilterTouchesWhenObscured(false);
+	}
+
+	public TapSafeFrameLayout(Context context, @Nullable AttributeSet attrs) {
+		super(context, attrs);
+		setFilterTouchesWhenObscured(false);
+	}
+
+	public TapSafeFrameLayout(Context context, @Nullable AttributeSet attrs,
+			@AttrRes int defStyleAttr) {
+		super(context, attrs, defStyleAttr);
+		setFilterTouchesWhenObscured(false);
+	}
+
+	public void setOnTapFilteredListener(OnTapFilteredListener listener) {
+		this.listener = listener;
+	}
+
+	@Override
+	public boolean onFilterTouchEventForSecurity(MotionEvent e) {
+		boolean filter = (e.getFlags() & FLAG_WINDOW_IS_OBSCURED) != 0;
+		if (filter && listener != null) listener.onTapFiltered();
+		return !filter;
+	}
+
+	public interface OnTapFilteredListener {
+		void onTapFiltered();
+	}
+}

briar-android/src/main/java/org/briarproject/briar/api/android/ScreenFilterMonitor.java

@@ -11,5 +11,5 @@ public interface ScreenFilterMonitor {
 	Set<String> getApps();
 
 	@UiThread
-	void storeAppsAsShown(Collection<String> s, boolean persistent);
+	void storeAppsAsShown(Collection<String> shown);
 }