add screen to display when no crypto provider is configured

k9mail/src/main/java/com/fsck/k9/mailstore/CryptoResultAnnotation.java

@@ -159,5 +159,6 @@ public final class CryptoResultAnnotation {
         OPENPGP_ENCRYPTED_BUT_INCOMPLETE,
         SIGNED_BUT_UNSUPPORTED,
         ENCRYPTED_BUT_UNSUPPORTED,
+        OPENPGP_ENCRYPTED_NO_PROVIDER,
     }
 }

k9mail/src/main/java/com/fsck/k9/ui/crypto/MessageCryptoSplitter.java

@@ -12,6 +12,7 @@ import com.fsck.k9.crypto.MessageDecryptVerifier;
 import com.fsck.k9.mail.Message;
 import com.fsck.k9.mail.Part;
 import com.fsck.k9.mailstore.CryptoResultAnnotation;
+import com.fsck.k9.mailstore.CryptoResultAnnotation.CryptoError;
 
 
 public class MessageCryptoSplitter {
@@ -19,20 +20,21 @@ public class MessageCryptoSplitter {
 
     @Nullable
     public static CryptoMessageParts split(@NonNull Message message, @Nullable MessageCryptoAnnotations annotations) {
-        if (annotations == null) {
+        ArrayList<Part> extraParts = new ArrayList<>();
+        Part primaryPart = MessageDecryptVerifier.findPrimaryEncryptedOrSignedPart(message, extraParts);
+        if (primaryPart == null) {
             return null;
         }
 
-        ArrayList<Part> extraParts = new ArrayList<>();
+        if (annotations == null) {
-        Part primaryPart = MessageDecryptVerifier.findPrimaryEncryptedOrSignedPart(message, extraParts);
+            CryptoResultAnnotation rootPartAnnotation =
-
+                    CryptoResultAnnotation.createErrorAnnotation(CryptoError.OPENPGP_ENCRYPTED_NO_PROVIDER, null);
-        if (!annotations.has(primaryPart)) {
+            return new CryptoMessageParts(primaryPart, rootPartAnnotation, extraParts);
-            return null;
         }
 
         CryptoResultAnnotation rootPartAnnotation = annotations.get(primaryPart);
         Part rootPart;
-        if (rootPartAnnotation.hasReplacementData()) {
+        if (rootPartAnnotation != null && rootPartAnnotation.hasReplacementData()) {
             rootPart = rootPartAnnotation.getReplacementData();
         } else {
             rootPart = primaryPart;
@@ -43,11 +45,12 @@ public class MessageCryptoSplitter {
 
     public static class CryptoMessageParts {
         public final Part contentPart;
+        @Nullable
         public final CryptoResultAnnotation contentCryptoAnnotation;
 
         public final List<Part> extraParts;
 
-        CryptoMessageParts(Part contentPart, CryptoResultAnnotation contentCryptoAnnotation, List<Part> extraParts) {
+        CryptoMessageParts(Part contentPart, @Nullable CryptoResultAnnotation contentCryptoAnnotation, List<Part> extraParts) {
             this.contentPart = contentPart;
             this.contentCryptoAnnotation = contentCryptoAnnotation;
             this.extraParts = Collections.unmodifiableList(extraParts);

k9mail/src/main/java/com/fsck/k9/ui/messageview/MessageCryptoPresenter.java

@@ -116,6 +116,11 @@ public class MessageCryptoPresenter implements OnCryptoClickListener {
                 break;
             }
 
+            case ENCRYPTED_NO_PROVIDER: {
+                messageView.showNoCryptoProviderConfigured(messageViewInfo);
+                break;
+            }
+
             case INCOMPLETE_SIGNED:
             case UNSUPPORTED_SIGNED:
             default: {

k9mail/src/main/java/com/fsck/k9/ui/messageview/MessageTopView.java

@@ -189,6 +189,21 @@ public class MessageTopView extends LinearLayout {
         displayViewOnLoadFinished(false);
     }
 
+    public void showNoCryptoProviderConfigured(MessageViewInfo messageViewInfo) {
+        resetAndPrepareMessageView(messageViewInfo);
+        View view = mInflater.inflate(R.layout.message_content_crypto_no_provider, containerView, false);
+
+        view.findViewById(R.id.crypto_settings).setOnClickListener(new OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                // TODO
+            }
+        });
+
+        containerView.addView(view);
+        displayViewOnLoadFinished(false);
+    }
+
     private void setCryptoProviderIcon(Drawable openPgpApiProviderIcon, View view) {
         ImageView cryptoProviderIcon = (ImageView) view.findViewById(R.id.crypto_error_icon);
         if (openPgpApiProviderIcon != null) {

k9mail/src/main/java/com/fsck/k9/view/MessageCryptoDisplayStatus.java

@@ -136,6 +136,12 @@ public enum MessageCryptoDisplayStatus {
             R.string.crypto_msg_signed_unencrypted, R.string.crypto_msg_sign_incomplete
     ),
 
+    ENCRYPTED_NO_PROVIDER (
+            R.attr.openpgp_red,
+            R.drawable.status_lock_error,
+            R.string.crypto_msg_unsupported_encrypted
+    ),
+
     UNSUPPORTED_ENCRYPTED (
             R.attr.openpgp_red,
             R.drawable.status_lock_error,
@@ -214,6 +220,9 @@ public enum MessageCryptoDisplayStatus {
 
             case OPENPGP_ENCRYPTED_API_ERROR:
                 return ENCRYPTED_ERROR;
+
+            case OPENPGP_ENCRYPTED_NO_PROVIDER:
+                return ENCRYPTED_NO_PROVIDER;
         }
         throw new IllegalStateException("Unhandled case!");
     }

k9mail/src/main/res/layout/message_content_crypto_no_provider.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:gravity="center_horizontal"
+    android:padding="16dp">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginLeft="8dp"
+        android:layout_marginRight="8dp"
+        android:id="@+id/crypto_error_title"
+        android:textAppearance="?android:textAppearanceMedium"
+        android:text="@string/crypto_no_provider_title"
+        />
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:layout_marginTop="30dp"
+        android:layout_marginBottom="30dp"
+        android:layout_marginLeft="20dp"
+        android:layout_marginRight="20dp"
+        android:text="@string/crypto_no_provider_message"
+        />
+
+    <Button
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:id="@+id/crypto_settings"
+        android:text="@string/crypto_no_provider_button"
+        />
+
+</LinearLayout>

k9mail/src/main/res/values/strings.xml

@@ -1163,6 +1163,7 @@ Please submit bug reports, contribute new features and ask questions at
 
     <string name="crypto_msg_encrypted_error">Message is encrypted, but there was a decryption error.</string>
     <string name="crypto_msg_signed_error">Message is signed, but the signature could not be verified.</string>
+    <string name="crypto_msg_encrypted_no_provider">Message is encrypted, but no crypto app is configured.</string>
     <string name="crypto_msg_unsupported_encrypted">Message is encrypted, but in an unsupported format.</string>
     <string name="crypto_msg_unsupported_signed">Message is signed, but in an unsupported format.</string>
     <string name="crypto_msg_incomplete_encrypted">Message is encrypted, but must be fully downloaded for decryption.</string>
@@ -1217,5 +1218,8 @@ Please submit bug reports, contribute new features and ask questions at
     <string name="apg_deprecated_ok">Got it!</string>
     <string name="apg">APG</string>
     <string name="no_crypto_provider_see_global">No OpenPGP app configured, see global settings!</string>
+    <string name="crypto_no_provider_title">This email is encrypted</string>
+    <string name="crypto_no_provider_message">This email has been encrypted with OpenPGP.\nTo read it, you need to install and configure a compatible OpenPGP App.</string>
+    <string name="crypto_no_provider_button">Choose OpenPGP App</string>
 
 </resources>