Android Architecture Components介绍
安卓架构组件是一套帮助开发者开发健壮，可测试，可维护的组件。
包含Handling Lifecycles,LiveData,ViewMode,Room.四个大方面，每个方面都可以单独使用。本次文章主要写第一个组件的简单使用。后续慢慢写完后面的内容。
Handling Lifecycles包含的内容
1.Lifecycle
2.LifecycleObserver
3.LifecycleOwner
Lifecycle简单介绍
- 定义具有Android生命周期的对象
- v4包的Fragment与FragmentActivity类实现了LifecycleOwner接口，通过接口里面的getLifecycle()方法获取Lifecycle对象。
- 我们可以在自己类里面实现LifecycleOwner接口。
- 包含事件Events与状态States
值得注意的是Android Architecture Components库还没正式发布。所以只有api 26.1.0及其之后的support library里面的Fragments和 Activities才实现了LifecycleOwner接口。如果是这之前的自定义的activities 和fragments需要实现LifecycleOwner 接口
Lifecycle events and states
LifecycleOwner简单介绍
- A class that has an Android lifecycle. These events can be used by custom components to handle lifecycle changes without implementing any code inside the Activity or the Fragment.
- 具有Android生命周期的接口
- 可以处理生命周期带来的变化却不需要在Activity或者Fragment中实现任何代码。
LifecycleObserver简单介绍
- 这是一个接口，用于将一个类标记为LifecycleObserver
- 接口里面没有任何方法，而是依赖于 {@lOnLifecycleEvent}注释方法。
简单示例
-
创建一个Activity与一个MyObserver类
- MainActivity主要代码。
本例用的api版本小于26.1.0，所以MainActivity需要自己实现LifecycleOwner
import android.arch.lifecycle.Lifecycle;
import android.arch.lifecycle.LifecycleOwner;
import android.arch.lifecycle.LifecycleRegistry;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity implements LifecycleOwner{
//LifecycleRegistry 实现了Lifecycle
private LifecycleRegistry mLifecycleRegistry=new LifecycleRegistry(MainActivity.this);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_next);
MyObserver myObserver = new MyObserver();
mLifecycleRegistry.addObserver(myObserver);
}
@Override
public Lifecycle getLifecycle() {
return mLifecycleRegistry;
}
}
- MyObserver代码
import android.arch.lifecycle.Lifecycle;
import android.arch.lifecycle.LifecycleObserver;
import android.arch.lifecycle.LifecycleOwner;
import android.arch.lifecycle.OnLifecycleEvent;
import android.util.Log;
/**
* Created by tony.zhang
* Email: tony.zhang.Mr@foxmail.com
*/
public class MyObserver implements LifecycleObserver {
private static final String TAG="MyObserver";
@OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
public void onCreated(){
Log.d(TAG, "onCreated: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_START)
public void onStart(){
Log.d(TAG, "onStart: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
public void onResume(){
Log.d(TAG, "onResume: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
public void onPause(){
Log.d(TAG, "onPause: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_STOP)
public void onStop(){
Log.d(TAG, "onStop: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
public void customMethod(){
Log.d(TAG, "customMethod: ");
}
@OnLifecycleEvent(Lifecycle.Event.ON_ANY)
public void onAny(){//此方法可以有参数，但类型必须如两者之一(LifecycleOwner owner,Lifecycle.Event event)
Log.d(TAG, "onAny: ");
}
}
- 打印消息
D/MyObserver: onCreated:
D/MyObserver: onAny:
D/MyObserver: onStart:
D/MyObserver: onAny:
D/MyObserver: onResume:
D/MyObserver: customMethod:
D/MyObserver: onAny:
- 退出Activity打印的消息
D/MyObserver: onPause:
D/MyObserver: onAny:
D/MyObserver: onStop:
D/MyObserver: onAny:
D/MyObserver: onAny:
- home键隐藏Activity打印消息
D/MyObserver: onPause:
D/MyObserver: onAny:
D/MyObserver: onStop:
D/MyObserver: onAny:
- 回到Activity打印消息
D/MyObserver: onStart:
D/MyObserver: onAny:
D/MyObserver: onResume:
D/MyObserver: customMethod:
D/MyObserver: onAny:
最后注意
- 在项目gradle文件里面添加maven { url 'https://maven.google.com' }
allprojects {
repositories {
jcenter()
maven { url 'https://maven.google.com' }
}
}
- 在子模块的gradle文件里添加library
compile 'android.arch.lifecycle:extensions:1.0.0-beta1'
compile 'android.arch.lifecycle:runtime:1.0.0'
annotationProcessor 'android.arch.lifecycle:compiler:1.0.0-beta1'
附录传送门
官方文档: https://developer.android.com/topic/libraries/architecture/lifecycle.html#lc-bp
demo :https://github.com/Totomiz/AndroidArchitectureComponets
