Show a snackbar when trying to download/install invalid updates

Instead of disabling the action button, keep it enabled and make it
show a snackbar to inform the user about the impossibility of
installing the selected update.

res/values/strings.xml

@@ -64,6 +64,8 @@
     <string name="snack_download_verification_failed">The update verification failed.</string>
     <string name="snack_download_verified">Download completed.</string>
 
+    <string name="snack_update_not_installable">This update can\'t be installed on top of the current build.</string>
+
     <string name="header_title_text">LineageOS\n%1$s</string>
     <string name="header_android_version">Android <xliff:g id="version" example="7.1.2">%1$s</xliff:g></string>
     <string name="header_last_updates_check">Last checked: <xliff:g id="date" example="1 January 1970">%1$s</xliff:g> (<xliff:g id="time" example="01:23">%2$s</xliff:g>)</string>

src/org/lineageos/updater/UpdatesActivity.java

@@ -41,6 +41,7 @@ import android.support.v7.widget.Toolbar;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
+import android.view.View;
 import android.widget.TextView;
 
 import org.json.JSONException;
@@ -75,7 +76,8 @@ public class UpdatesActivity extends AppCompatActivity {
         setContentView(R.layout.activity_updates);
 
         RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
-        mAdapter = new UpdatesListAdapter(this);
+        View containerView = findViewById(R.id.main_container);
+        mAdapter = new UpdatesListAdapter(this, containerView);
         recyclerView.setAdapter(mAdapter);
         RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
         recyclerView.setLayoutManager(layoutManager);

src/org/lineageos/updater/UpdatesListAdapter.java

@@ -17,6 +17,7 @@ package org.lineageos.updater;
 
 import android.content.Context;
 import android.content.DialogInterface;
+import android.support.design.widget.Snackbar;
 import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.RecyclerView;
 import android.text.format.DateUtils;
@@ -49,6 +50,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     private List<String> mDownloadIds;
     private UpdaterControllerInt mUpdaterController;
     private Context mContext;
+    private View mContainerView;
 
     private enum Action {
         DOWNLOAD,
@@ -86,8 +88,9 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
         }
     }
 
-    public UpdatesListAdapter(Context context) {
+    public UpdatesListAdapter(Context context, View containerView) {
         mContext = context;
+        mContainerView = containerView;
 
         TypedValue tv = new TypedValue();
         context.getTheme().resolveAttribute(android.R.attr.disabledAlpha, tv, true);
@@ -115,7 +118,6 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
 
         boolean busy = mUpdaterController.hasActiveDownloads() ||
                 mUpdaterController.isVerifyingUpdate();
-        boolean enabled = !busy && Utils.canInstall(update);
 
         boolean canDelete = false;
 
@@ -150,7 +152,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
             viewHolder.mProgressPercentage.setText(NumberFormat.getPercentInstance().format(1));
         } else {
             canDelete = true;
-            setButtonAction(viewHolder.mAction, Action.RESUME, downloadId, enabled);
+            setButtonAction(viewHolder.mAction, Action.RESUME, downloadId, !busy);
             String downloaded = Formatter.formatBytes(mContext.getResources(),
                     update.getFile().length(), Formatter.FLAG_SHORTER).value;
             String total = Formatter.formatShortFileSize(mContext, update.getFileSize());
@@ -174,15 +176,14 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
 
         boolean busy = mUpdaterController.hasActiveDownloads() ||
                 mUpdaterController.isVerifyingUpdate();
-        boolean enabled = !busy && Utils.canInstall(update);
 
         if (update.getPersistentStatus() == UpdateStatus.Persistent.VERIFIED) {
             viewHolder.itemView.setOnLongClickListener(
                     getDeleteClickListener(update.getDownloadId()));
-            setButtonAction(viewHolder.mAction, Action.INSTALL, update.getDownloadId(), enabled);
+            setButtonAction(viewHolder.mAction, Action.INSTALL, update.getDownloadId(), !busy);
         } else {
             viewHolder.itemView.setOnLongClickListener(null);
-            setButtonAction(viewHolder.mAction, Action.DOWNLOAD, update.getDownloadId(), enabled);
+            setButtonAction(viewHolder.mAction, Action.DOWNLOAD, update.getDownloadId(), !busy);
         }
     }
 
@@ -275,30 +276,46 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
                     }
                 });
                 break;
-            case RESUME:
+            case RESUME: {
                 button.setImageResource(R.drawable.ic_resume);
                 button.setContentDescription(
                         mContext.getString(R.string.action_description_resume));
                 button.setEnabled(enabled);
+                UpdateDownload update = mUpdaterController.getUpdate(downloadId);
+                final boolean canInstall = Utils.canInstall(update);
                 button.setOnClickListener(!enabled ? null : new View.OnClickListener() {
                     @Override
                     public void onClick(View view) {
-                        mUpdaterController.resumeDownload(downloadId);
+                        if (canInstall) {
+                            mUpdaterController.resumeDownload(downloadId);
+                        } else {
+                            showSnackbar(R.string.snack_update_not_installable,
+                                    Snackbar.LENGTH_LONG);
+                        }
                     }
                 });
-                break;
+            }
-            case INSTALL:
+            break;
+            case INSTALL: {
                 button.setImageResource(R.drawable.ic_system_update);
                 button.setContentDescription(
                         mContext.getString(R.string.action_description_install));
                 button.setEnabled(enabled);
+                UpdateDownload update = mUpdaterController.getUpdate(downloadId);
+                final boolean canInstall = Utils.canInstall(update);
                 button.setOnClickListener(!enabled ? null : new View.OnClickListener() {
                     @Override
                     public void onClick(View view) {
-                        getInstallDialog(downloadId).show();
+                        if (canInstall) {
+                            getInstallDialog(downloadId).show();
+                        } else {
+                            showSnackbar(R.string.snack_update_not_installable,
+                                    Snackbar.LENGTH_LONG);
+                        }
                     }
                 });
-                break;
+            }
+            break;
         }
         button.setAlpha(enabled ? 1.f : mAlphaDisabledValue);
     }
@@ -327,6 +344,10 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
         };
     }
 
+    private void showSnackbar(int stringId, int duration) {
+        Snackbar.make(mContainerView, stringId, duration).show();
+    }
+
     private AlertDialog.Builder getInstallDialog(final String downloadId) {
         UpdateDownload update = mUpdaterController.getUpdate(downloadId);
         int resId;