Give better feedback when a firmware cannot be installed #234

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/MiBandFWHelper.java

@@ -26,12 +26,13 @@ public class MiBandFWHelper {
 
     private final Uri uri;
     private final ContentResolver cr;
-    private final
+    /**
-    @NonNull
+     * The backing firmware info instance, which in general supports the provided
-    AbstractMiFirmwareInfo firmwareInfo;
+     * given firmware. You must call AbstractMiFirmwareInfo#checkValid() before
-    private final
+     * attempting to flash it.
-    @NonNull
+     */
-    byte[] fw;
+    private final @NonNull AbstractMiFirmwareInfo firmwareInfo;
+    private final @NonNull byte[] fw;
 
     /**
      * Provides a different notification API which is also used on Mi1A devices.
@@ -139,6 +140,11 @@ public class MiBandFWHelper {
         return AbstractMiFirmwareInfo.determineFirmwareInfoFor(wholeFirmwareBytes);
     }
 
+    /**
+     * The backing firmware info instance, which in general supports the provided
+     * given firmware. You MUST call AbstractMiFirmwareInfo#checkValid() AND
+     * isGenerallyCompatibleWithDevice() before attempting to flash it.
+     */
     public AbstractMiFirmwareInfo getFirmwareInfo() {
         return firmwareInfo;
     }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/MiBandFWInstallHandler.java

@@ -47,6 +47,14 @@ public class MiBandFWInstallHandler implements InstallHandler {
             return;
         }
 
+        try {
+            helper.getFirmwareInfo().checkValid();
+        } catch (IllegalArgumentException ex) {
+            installActivity.setInfoText(ex.getLocalizedMessage());
+            installActivity.setInstallEnabled(false);
+            return;
+        }
+
         GenericItem fwItem = new GenericItem(mContext.getString(R.string.miband_installhandler_miband_firmware, helper.getHumanFirmwareVersion()));
         fwItem.setIcon(R.drawable.ic_device_miband);
 

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/AbstractMiFirmwareInfo.java

@@ -23,7 +23,6 @@ public abstract class AbstractMiFirmwareInfo {
             throw new IllegalArgumentException("Unsupported data (maybe not even a firmware?).");
         }
         if (candidates.length == 1) {
-            candidates[0].checkValid();
             return candidates[0];
         }
         throw new IllegalArgumentException("don't know for which device the firmware is, matches multiple devices");
@@ -60,10 +59,24 @@ public abstract class AbstractMiFirmwareInfo {
 
     public abstract int getFirmwareVersion();
 
+    /**
+     * Returns true if the firmware data is recognized as such and can be
+     * handled by this instance. No further sanity checks are done at this point.
+     */
     protected abstract boolean isGenerallySupportedFirmware();
 
+    /**
+     * This method checks whether the firmware data is recognized as such and can be handled
+     * by this instance. It will be called by #isGenerallySupportedFirmware() in order to check
+     * whether this instance can be used at all or shall be thrown away.
+     */
     protected abstract boolean isHeaderValid();
 
+    /**
+     * Checks whether this instance, with the provided firmware data is compatible with the
+     * given device. Must be called to avoid installing Mi1 firmware on Mi1A, for example.
+     * @param device
+     */
     public abstract boolean isGenerallyCompatibleWith(GBDevice device);
 
     public @NonNull byte[] getFirmwareBytes() {
@@ -80,6 +93,11 @@ public abstract class AbstractMiFirmwareInfo {
 
     public abstract boolean isSingleMiBandFirmware();
 
+    /**
+     * Performs a thorough sanity check of the firmware data and throws IllegalArgumentException
+     * if there's any problem with it.
+     * @throws IllegalArgumentException
+     */
     public void checkValid() throws IllegalArgumentException {
     }