1. Service 服务 （是一个没有用户界面的在后台运行执行耗时操作的应用组件）
第一种方式： (startService 未绑定, 当程序退出,若没有停止服务则会继续在后台运行)
//继承 Service public class MyService extends Service { private String tag = "MyService"; @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub return null; } @Override public void onCreate() { // TODO Auto-generated method stub super.onCreate(); Log.i(tag , "onCreate"); } }
<!-- 清单中声明 --> <service android:name=".MyService"></service>
//开启服务 intent = new Intent(this, MyService.class); startService(intent);
//停止服务 stopService(intent); |
第二种方式： (绑定服务)
//继承 Service public class MyService extends Service { private String tag = "MyService"; @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub return new MyBind(); } public class MyBind extends Binder implements IServices { @Override public void test() { myTest(); } } private void myTest() { Log.i(tag, "test in service"); } }
//binder 中的接口 public interface IServices { void test(); }
//开启服务 intent = new Intent(this, MyService.class); bindService(intent, conn , Context.BIND_AUTO_CREATE); mIsBound = true;
if (mIsBound) { unbindService(conn); }
private ServiceConnection conn = new ServiceConnection() { @Override public void onServiceDisconnected(ComponentName name) { } @Override public void onServiceConnected(ComponentName name, IBinder service) { iServices = (IServices)service; Log.i(tag, "onServiceConnected"); } };
//调用服务中的函数 public void onTest(View view) { iServices.test(); } |
远程调用Service
调用其他程序提供的Service, 其用到了aidl技术. 其他和调用本地无异. 只需将interface 的 public 修饰符去掉即可, 后缀改为aidl.
编译器将自动在gen目录下生成相应的.java 文件, 其中的Stub 子类实现了接口.
服务端: //aidl 接口定义 interface IServices { void test(); }
public class RemoteService extends Service { private String tag = "RemoteService"; @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub return new MyBinder(); } private class MyBinder extends IServices.Stub{ @Override public void test() throws RemoteException { myTest(); } } private void myTest() { Log.i(tag, "test in service"); } }
<!-- 清单注册,并添加action --> <service android:name=".RemoteService"> <intent-filter > <action android:name="cn.lt.RemoteService"/> </intent-filter> </service>
在调用端我们需要添加其服务端定义的aidl到工程中,其包名需要和服务端的一致.
private IServices iServices;
//绑定 Intent intent = new Intent(); intent.setAction("cn.lt.RemoteService"); bindService(intent, new MyConn(), BIND_AUTO_CREATE);
private class MyConn implements ServiceConnection { @Override public void onServiceConnected(ComponentName name, IBinder service) { iServices = IServices.Stub.asInterface(service); } @Override public void onServiceDisconnected(ComponentName name) { } }
//调用服务中的函数 iServices.test();
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2. Java 反射机制 （是一个没有用户界面的在后台运行执行耗时操作的应用组件）
Class 类
Class 类为 Java 反射的源头, 通过该类能得到一个类的完整结构. (在android 开发中, 可通过反射机制得到系统中隐藏的服务.) //反射测试类 public class Person { public Person(){}; public static void sayHello() { System.out.println("Hello World"); } public void sayHello(String name) { System.out.println("Hello "+name); } public int add(int a, int b) { return a+b; } }
//--------------------------------- public static void main(String[] args) { try { //得到 Person 类对象 Class c = Class.forName("cn.lt.Test.Person"); //得到 sayHello 方法 Method method1 = c.getMethod("sayHello"); method1.invoke(null); //调用静态方法可传null Method method2 = c.getMethod("sayHello", String.class); method2.invoke(c.newInstance(), new Object[]{"Ty"}); Method method3 = c.getMethod("add", int.class, int.class); System.out.println(method3.invoke(c.newInstance(), new Object[]{1, 2})); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } |
