问题
I have this annotation
class Target{
final String value;
const Target(this.value);
}
and 2 classes that are annotated with it
@Target("/313")
class c1{
}
@Target("/314")
class c2{
}
how can i get a List of ClassMirror instances for the classes that have the Target annotation?
based on the selected answer that is if i knew what library my calsses exist in
var mirrorSystem = currentMirrorSystem();
var libraryMirror = mirrorSystem.findLibrary(#testlib);
for(ClassMirror classMirror in libraryMirror.declarations.values){
if(classMirror.metadata!=null){
for(var meta in classMirror.metadata){
if(meta.type == reflectClass(Path)){
print(classMirror.simpleName);
print(meta.getField(#value));
}
}
}
}
回答1:
This searches all libraries in the current isolate for classes that are annotated with @Target('/313')
@MirrorsUsed(metaTargets: Target) // might be necessary when you build this code to JavaScript
import 'dart:mirrors';
class Target {
final String id;
const Target(this.id);
}
@Target('/313')
class c1{
}
@Target('/314')
class c2{
}
@Target('/313')
@Target('/314')
class c3{
}
void main() {
MirrorSystem mirrorSystem = currentMirrorSystem();
mirrorSystem.libraries.forEach((lk, l) {
l.declarations.forEach((dk, d) {
if(d is ClassMirror) {
ClassMirror cm = d as ClassMirror;
cm.metadata.forEach((md) {
InstanceMirror metadata = md as InstanceMirror;
if(metadata.type == reflectClass(Target) && metadata.getField(#id).reflectee == '/313') {
print('found: ${cm.simpleName}');
}
});
}
});
});
}
found: Symbol("c3")
found: Symbol("c1")
来源：https://stackoverflow.com/questions/24457283/getting-classmirror-instances-for-all-classes-that-have-an-annotation