注解主要有以下幾個來源：
- Java中的注解：
- 元注解 位于java.lang.annotation包中 @Documented @Inherited @Repeatable @Retention @Target
- 普通注解位于java.lang包中 @Override@Deprecated @FunctionalInterface(1.8后) @SuppressWarnings
- Android 原生注解：
位于android.annotation包中 @TargetApi @SuppressLint
-
Android Support中的注解 ：
位于android.support.annotation包中疲迂。@Nullable @NonNull @CheckResult @ColorRes(資源引用) @Size @IntRange(范圍) @MainThread(線程) @Keep(Proguard) @RequiresPermission @RequiresApiss
通過appcompat-v7依賴間接引入 (compile 'com.android.support:appcompat-v7:XXX')
直接引入(compile ‘com.android.support:support-annotations:XXX’)
-
AndroidAnnotations注解
位于org.androidannotations.annotations包中尝蠕。
包引入：compile "org.androidannotations:androidannotations-api: $AAVersion"注解處理器引入:annotationProcessor "org.androidannotations:androidannotations:$AAVersion"
自定義注解
環(huán)境配置
Android Support配置
在build.gradle中加入依賴:
dependencies {
compile 'com.android.support:support-annotations:XXX'
}
如果依賴中有appcompat-v7空繁，該包默認(rèn)依賴support-annotations舔琅，不用再配置
image.png
support-annotations包中的內(nèi)容如下：
image.png
AndroidAnnotation配置
def AAVersion = 'XXX'
dependencies {
annotationProcessor "org.androidannotations:androidannotations:$AAVersion"
compile "org.androidannotations:androidannotations-api:$AAVersion"
}
androidannotations包中的內(nèi)容如下：
image.png
官網(wǎng)：http://androidannotations.org/
AndroidAnnotation Features(AA特性)
- Dependency injection(依賴注入 ): inject views, extras, system services, resources, ...
- Simplified threading model(簡化了線程操作): annotate your methods so that they execute on the UI thread or on a background thread.
- Event binding(事件綁定): annotate methods to handle events on views, no more ugly anonymous listener classes!
- REST client(REST支持): create a client interface, AndroidAnnotations generates the implementation.
- No magic(AA不是魔法，只是生成了"SampleActivity_"的子類): As AndroidAnnotations generate subclasses at compile time, you can check the code to see how it works.
- 體積小捏悬，無反射佩脊， 無運(yùn)行時影響，所以性能也不會受到影響 AndroidAnnotations provide those good things and even more for less than 150kb, without any runtime perf impact!
用法：
關(guān)于Android Support注解常用的用法參考：
AndroidAnnotations框架詳解
關(guān)于AndroidAnnotation注解常用用法參考：
List of all available annotations
自定義Annotation插件
參考Creating an AndroidAnnotations plugin
- 創(chuàng)建兩個Java Model,名字可以隨便起
image.png
- annotationtostring-api:包含自定義的注解@ToString
apply plugin: 'java'
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
}
sourceCompatibility = "1.7"
targetCompatibility = "1.7"
- annotationtostring:定義注解處理器随闽，及生成代碼Api父丰，需要依賴annotationtostring-api Model,及org.androidannotations:androidannotations
apply plugin: 'java'
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile project(':annotationtostring-api')
compile 'org.androidannotations:androidannotations:4.4.0'
compile 'com.helger:jcodemodel:3.0.1'//用于生成 Java 代碼的 Java 庫
}
sourceCompatibility = "1.7"
targetCompatibility = "1.7"
- 確定一個唯一的名稱：例如ToString
- annotationtostring-api中創(chuàng)建文件 tostring-api.properties,內(nèi)容如下:
version=1.0
- annotationtostring中創(chuàng)建文件 tostring.properties,內(nèi)容如下:
version=1.0
- annotationtostring-api中創(chuàng)建Annotation
@Retention(RetentionPolicy.CLASS) // required
@Target(ElementType.TYPE) // this can vary per annotation
public @interface ToString {
}
- annotationtostring中創(chuàng)建META-INF/services/org.androidannotations.plugin.AndroidAnnotationsPlugin文件，內(nèi)容為：
com.example.ToStringPlugin
image.png
- annotationtostring中創(chuàng)建注解處理器
插件的接入類掘宪，繼承自AndroidAnnotationsPlugin
public class ToStringPlugin extends AndroidAnnotationsPlugin {
@Override
public String getName() {
return "ToString";
}
@Override
public List<AnnotationHandler<?>> getHandlers(AndroidAnnotationsEnvironment androidAnnotationEnv) {
List<AnnotationHandler<?>> handlers = new ArrayList<>();
handlers.add(new ToStringHandler(androidAnnotationEnv));
return handlers;
}
}
創(chuàng)建真正的處理類蛾扇，該類會處理并驗證注解
public class ToStringHandler extends BaseAnnotationHandler<EComponentHolder> {
public ToStringHandler(AndroidAnnotationsEnvironment environment) {
super(ToString.class, environment); // this handles your @ToString annotation
}
@Override
protected void validate(Element element, ElementValidation validation) {
validatorHelper.enclosingElementHasEnhancedComponentAnnotation(element, validation);//該注解只能用在以@E注解開頭的加強(qiáng)類中，但MainActivity中即使添加了@EActivity注解魏滚，最后還是報以下編譯錯誤镀首，注掉不驗證便可。
}
@Override
public void process(Element element, EComponentHolder holder) throws Exception {
JMethod toString = holder.getGeneratedClass().method(JMod.PUBLIC, getClasses().STRING, "toString");
toString.body()._return(JExpr.lit("Hello, AndroidAnnotations!"));
toString.annotate(Override.class);
}
}
錯誤:
com.example.note.ToString can only be used in a package annotated with
@interface org.androidannotations.annotations.EApplication,
@interface org.androidannotations.annotations.EActivity,
@interface org.androidannotations.annotations.EViewGroup,
@interface org.androidannotations.annotations.EView,
@interface org.androidannotations.annotations.EBean,
@interface org.androidannotations.annotations.EService,
@interface org.androidannotations.annotations.EIntentService,
@interface org.androidannotations.annotations.EReceiver,
@interface org.androidannotations.annotations.EProvider,
@interface org.androidannotations.annotations.EFragment.
警告:
Element com.minicup.annotation.MainActivity invalidated by ToStringHandler
- Build 后生成 MainActivity_
@EActivity(R.layout.activity_main)
@ToString
public class MainActivity extends AppCompatActivity {
}
public final class MainActivity_ extends MainActivity implements HasViews{
@Override
public String toString() {
return "Hello, AndroidAnnotations!";
}
}
參考：
AndroidAnnotations框架詳解
Android注解（Annotation）知識點(diǎn)總結(jié)整理
官網(wǎng)
Android注解AndroidAnnotation的使用及實現(xiàn)流程分析
