Use onBackPressed instead of onKeyDown (#1943)

appinventor/components/src/com/google/appinventor/components/runtime/Form.java

@@ -560,22 +560,14 @@ public class Form extends AppInventorCompatActivity
 
   /*
    * Here we override the hardware back button, just to make sure
-   * that the closing screen animation is applied. (In API level
-   * 5, we can simply override the onBackPressed method rather
-   * than bothering with onKeyDown)
+   * that the closing screen animation is applied.
    */
   @Override
-  public boolean onKeyDown(int keyCode, KeyEvent event) {
-    if (keyCode == KeyEvent.KEYCODE_BACK) {
-      if (!BackPressed()) {
-        boolean handled = super.onKeyDown(keyCode, event);
-        AnimationUtil.ApplyCloseScreenAnimation(this, closeAnimType);
-        return handled;
-      } else {
-        return true;
-      }
+  public void onBackPressed() {
+    if (!BackPressed()) {
+      AnimationUtil.ApplyCloseScreenAnimation(this, closeAnimType);
     }
-    return super.onKeyDown(keyCode, event);
+    super.onBackPressed();
   }
 
   @SimpleEvent(description = "Device back button pressed.")

appinventor/components/src/com/google/appinventor/components/runtime/ListPickerActivity.java

@@ -157,15 +157,11 @@ public class ListPickerActivity extends AppInventorCompatActivity implements Ada
   }
 
   // Capture the hardware back button to make sure the screen animation
-  // still applies. (In API level 5, we can override onBackPressed instead)
+  // still applies.
   @Override
-  public boolean onKeyDown(int keyCode, KeyEvent event) {
-    if (keyCode == KeyEvent.KEYCODE_BACK) {
-      boolean handled = super.onKeyDown(keyCode, event);
-      AnimationUtil.ApplyCloseScreenAnimation(this, closeAnim);
-      return handled;
-    }
-    return super.onKeyDown(keyCode, event);
+  public void onBackPressed() {
+    AnimationUtil.ApplyCloseScreenAnimation(this, closeAnim);
+    super.onBackPressed();
   }