42 lines
918 B
Dart
42 lines
918 B
Dart
typedef NavigationGuardCallback = Future<bool> Function();
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class NavigationGuard {
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static NavigationGuardCallback? _callback;
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static void register(NavigationGuardCallback callback) {
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_callback = callback;
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}
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static void unregister([NavigationGuardCallback? callback]) {
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if (callback == null || identical(_callback, callback)) {
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_callback = null;
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_promptActive = false;
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}
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}
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static Future<void> attemptNavigation(
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Future<void> Function() performNavigation,
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) async {
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if (_promptActive) return;
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final cb = _callback;
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if (cb == null) {
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await performNavigation();
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return;
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}
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_promptActive = true;
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bool allow = false;
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try {
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allow = await cb();
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} catch (_) {
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allow = false;
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} finally {
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_promptActive = false;
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}
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if (allow) {
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await performNavigation();
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}
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}
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static bool _promptActive = false;
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}
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