Fixed a potential memory leak when showing progress dialogs

Author: ajungg

ui/src/main/java/io/snabble/sdk/ui/cart/ShoppingCartView.java

@@ -258,48 +258,54 @@ private void onCartUpdated() {
         }
     }
 
+    public void registerListeners() {
+        cart.addListener(shoppingCartListener);
+        checkout.addOnCheckoutStateChangedListener(ShoppingCartView.this);
+
+        progressDialog.setOnCancelListener(onCancelListener);
+    }
+
+    public void unregisterListeners() {
+        cart.removeListener(shoppingCartListener);
+        checkout.removeOnCheckoutStateChangedListener(ShoppingCartView.this);
+
+        progressDialog.setOnCancelListener(null);
+        progressDialog.dismiss();
+    }
+
     @Override
-    protected void onAttachedToWindow() {
+    public void onAttachedToWindow() {
         super.onAttachedToWindow();
 
-        cart.addListener(shoppingCartListener);
-        checkout.addOnCheckoutStateChangedListener(this);
-
         Application application = (Application) getContext().getApplicationContext();
         application.registerActivityLifecycleCallbacks(activityLifecycleCallbacks);
 
-        progressDialog.setOnCancelListener(onCancelListener);
+        registerListeners();
     }
 
     @Override
-    protected void onDetachedFromWindow() {
+    public void onDetachedFromWindow() {
         super.onDetachedFromWindow();
 
-        cart.removeListener(shoppingCartListener);
-        checkout.removeOnCheckoutStateChangedListener(this);
-
         Application application = (Application) getContext().getApplicationContext();
         application.unregisterActivityLifecycleCallbacks(activityLifecycleCallbacks);
 
-        progressDialog.setOnCancelListener(null);
-        progressDialog.dismiss();
+        unregisterListeners();
     }
 
     private Application.ActivityLifecycleCallbacks activityLifecycleCallbacks =
             new SimpleActivityLifecycleCallbacks() {
                 @Override
                 public void onActivityStarted(Activity activity) {
                     if (UIUtils.getHostActivity(getContext()) == activity) {
-                        cart.addListener(shoppingCartListener);
-                        checkout.addOnCheckoutStateChangedListener(ShoppingCartView.this);
+                        registerListeners();
                     }
                 }
 
                 @Override
                 public void onActivityStopped(Activity activity) {
                     if (UIUtils.getHostActivity(getContext()) == activity) {
-                        cart.removeListener(shoppingCartListener);
-                        checkout.removeOnCheckoutStateChangedListener(ShoppingCartView.this);
+                        unregisterListeners();
                     }
                 }
             };

ui/src/main/java/io/snabble/sdk/ui/scanner/SelfScanningView.java

@@ -328,53 +328,64 @@ public void removeBarcodeFormat(BarcodeFormat barcodeFormat) {
         barcodeScanner.removeBarcodeFormat(barcodeFormat);
     }
 
-    @Override
-    public void onAttachedToWindow() {
-        super.onAttachedToWindow();
+    public void registerListeners() {
+        isRunning = true;
 
         progressDialog.setOnCancelListener(progressDialogCancelListener);
-        checkout.addOnCheckoutStateChangedListener(this);
+        checkout.addOnCheckoutStateChangedListener(SelfScanningView.this);
 
         startBarcodeScanner();
+    }
+
+    public void unregisterListeners() {
+        isRunning = false;
+
+        stopBarcodeScanner();
+        checkout.removeOnCheckoutStateChangedListener(SelfScanningView.this);
+
+        progressDialog.setOnCancelListener(null);
+        progressDialog.dismiss();
+        productDialog.dismiss();
+    }
+
+    @Override
+    public void onAttachedToWindow() {
+        super.onAttachedToWindow();
 
         Application application = (Application) getContext().getApplicationContext();
         application.registerActivityLifecycleCallbacks(activityLifecycleCallbacks);
+
+        registerListeners();
     }
 
     @Override
     public void onDetachedFromWindow() {
         super.onDetachedFromWindow();
 
-        stopBarcodeScanner();
-        checkout.removeOnCheckoutStateChangedListener(this);
-
         Application application = (Application) getContext().getApplicationContext();
         application.unregisterActivityLifecycleCallbacks(activityLifecycleCallbacks);
 
-        progressDialog.setOnCancelListener(null);
-        progressDialog.dismiss();
-        productDialog.dismiss();
+        unregisterListeners();
     }
 
     private Application.ActivityLifecycleCallbacks activityLifecycleCallbacks =
             new SimpleActivityLifecycleCallbacks() {
                 @Override
-                public void onActivityResumed(Activity activity) {
+                public void onActivityStarted(Activity activity) {
                     if (UIUtils.getHostActivity(getContext()) == activity) {
-                        isRunning = true;
-                        startBarcodeScanner();
+                        registerListeners();
                     }
                 }
 
                 @Override
-                public void onActivityPaused(Activity activity) {
+                public void onActivityStopped(Activity activity) {
                     if (UIUtils.getHostActivity(getContext()) == activity) {
-                        isRunning = false;
-                        stopBarcodeScanner();
+                        unregisterListeners();
                     }
                 }
             };
 
+
     @Override
     public void onStateChanged(Checkout.State state) {
         if (!isShown()) {

ui/src/main/java/io/snabble/sdk/ui/utils/DelayedProgressDialog.java

@@ -7,24 +7,26 @@
 
 public class DelayedProgressDialog extends ProgressDialog {
     private Handler handler = new Handler(Looper.getMainLooper());
-    private Runnable runnable;
+
+    private Runnable showRunnable = new Runnable() {
+        public void run() {
+            if(!isDismissed) {
+                show();
+            }
+        }
+    };
+
     private boolean isDismissed = false;
 
     public DelayedProgressDialog(Context context) {
         super(context);
     }
 
     public void showAfterDelay(long afterDelayMs) {
-        runnable = new Runnable() {
-            public void run() {
-                if(!isDismissed) {
-                    show();
-                }
-            }
-        };
+        stopCallbacks();
 
         isDismissed = false;
-        handler.postDelayed(runnable, afterDelayMs);
+        handler.postDelayed(showRunnable, afterDelayMs);
     }
 
     @Override
@@ -41,7 +43,7 @@ public void cancel() {
 
     private void stopCallbacks() {
         isDismissed = true;
-        handler.removeCallbacks(runnable);
+        handler.removeCallbacks(showRunnable);
         setOnCancelListener(null);
     }