Summary:
Currently, the system for mapping JS event handlers to blocks is quite clean on the JS side, but is clunky on the native side. The event property is passed as a boolean, which can then be checked by the native side, and if true, the native side is supposed to send an event via the event dispatcher.
This diff adds the facility to declare the property as a block instead. This means that the event side can simply call the block, and it will automatically send the event. Because the blocks for bubbling and direct events are named differently, we can also use this to generate the event registration data and get rid of the arrays of event names.
The name of the event is inferred from the property name, which means that the property for an event called "load" must be called `onLoad` or the mapping won't work. This can be optionally remapped to a different property name on the view itself if necessary, e.g.
RCT_REMAP_VIEW_PROPERTY(onLoad, loadEventBlock, RCTDirectEventBlock)
If you don't want to use this mechanism then for now it is still possible to declare the property as a BOOL instead and use the old mechanism (this approach is now deprecated however, and may eventually be removed altogether).
Summary:
NavigatorIOS supports four new properties:
- **rightButtonImageSource:** The source of an image to display in the top right. This must be a static image since UINavigationController only supports UIImages. Adding support for UIImageViews (or arbitrary views) is more complicated because custom views do not fade on touch and do not have hit slop the same way that UIImage buttons do. Usage: `rightButtonImageSource: ix('ImageName')`
- **backButtonImageSource:** Use a custom image for the back button. This does not replace the back caret (`<`) but instead replaces the text next to it.
- **leftButtonTitle**: Text for the left nav button, which supersedes the previous nav item's back button when specified. The main use case for this is your initial screen/UIVC which has nothing to go back to (since it is the first VC on the stack) but need to display a left button. This does hide the back button if there would have been one otherwise.
- **leftButtonImageSource:** Image source for the left button, super
Closes https://github.com/facebook/react-native/pull/263
Github Author: James Ide <ide@jameside.com>
Test Plan: Imported from GitHub, without a `Test Plan:` line.