Allow scanning while device is locked

Show the camera and newly scanned results over the lock screen
while keeping history, media selection, and settings protected.

app/src/main/kotlin/de/markusfisch/android/binaryeye/activity/CameraActivity.kt

@@ -60,6 +60,7 @@ import de.markusfisch.android.binaryeye.media.releaseToneGenerators
 import de.markusfisch.android.binaryeye.net.isScanDeeplink
 import de.markusfisch.android.binaryeye.net.sendAsync
 import de.markusfisch.android.binaryeye.net.urlEncode
+import de.markusfisch.android.binaryeye.os.showWhenLocked
 import de.markusfisch.android.binaryeye.preference.Preferences
 import de.markusfisch.android.binaryeye.view.errorFeedback
 import de.markusfisch.android.binaryeye.view.initBars
@@ -190,6 +191,7 @@ class CameraActivity : AppCompatActivity() {
 
 	override fun onCreate(state: Bundle?) {
 		super.onCreate(state)
+		showWhenLocked()
 		setContentView(R.layout.activity_camera)
 
 		// Necessary to get the right translation after setting a
@@ -1081,7 +1083,7 @@ fun Activity.showResult(
 		return
 	}
 	if (!bulkMode) {
-		startActivity(DecodeActivity.newIntent(this, scan))
+		startActivity(DecodeActivity.newIntent(this, scan, showWhenLocked = true))
 	}
 }
 

app/src/main/kotlin/de/markusfisch/android/binaryeye/activity/DecodeActivity.kt

@@ -53,6 +53,7 @@ import de.markusfisch.android.binaryeye.io.askForFileName
 import de.markusfisch.android.binaryeye.io.toSaveResult
 import de.markusfisch.android.binaryeye.io.writeExternalFile
 import de.markusfisch.android.binaryeye.net.createEncodeDeeplink
+import de.markusfisch.android.binaryeye.os.showWhenLocked
 import de.markusfisch.android.binaryeye.view.hideSoftKeyboard
 import de.markusfisch.android.binaryeye.view.setPaddingFromWindowInsets
 import de.markusfisch.android.binaryeye.widget.toast
@@ -122,6 +123,9 @@ class DecodeActivity : AbstractBaseActivity() {
 
 	override fun onCreate(state: Bundle?) {
 		super.onCreate(state)
+		if (intent.getBooleanExtra(SHOW_WHEN_LOCKED, false)) {
+			showWhenLocked()
+		}
 		setScreenContentView(R.layout.activity_decode)
 		setTitle(R.string.content)
 
@@ -734,12 +738,18 @@ class DecodeActivity : AbstractBaseActivity() {
 		private const val SCAN_BUNDLE = "scan_bundle"
 		private const val OPEN_DOCUMENT = 1
 		private const val SCHEME_FILE = "file://"
+		private const val SHOW_WHEN_LOCKED = "show_when_locked"
 
-		fun newIntent(context: Context, scan: Scan): Intent {
+		fun newIntent(
+			context: Context,
+			scan: Scan,
+			showWhenLocked: Boolean = false
+		): Intent {
 			val args = Bundle()
 			args.putBundle(SCAN_BUNDLE, scan.toBundle())
 			return Intent(context, DecodeActivity::class.java).apply {
 				putExtra(DECODED_SCAN, true)
+				putExtra(SHOW_WHEN_LOCKED, showWhenLocked)
 				putExtras(args)
 			}
 		}

app/src/main/kotlin/de/markusfisch/android/binaryeye/os/LockScreen.kt

@@ -0,0 +1,14 @@
+package de.markusfisch.android.binaryeye.os
+
+import android.app.Activity
+import android.os.Build
+import android.view.WindowManager
+
+@Suppress("DEPRECATION")
+fun Activity.showWhenLocked() {
+	if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
+		setShowWhenLocked(true)
+	} else {
+		window.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED)
+	}
+}