android教程之service使用方法示例详解
service的生命周期 （适用于2.1及以上）
1. 被startservice的
无论是否有任何活动绑定到该service，都在后台运行。oncreate(若需要) -> onstart(int id, bundle args). 多次startservice，则onstart调用多次，但不会创建多个service实例，只需要一次stop。该service一直后台运行，直到stopservice或者自己的stopself()或者资源不足由平台结束。
2. 被bindservice的
调用bindservice绑定，连接建立服务一直运行。未被startservice只是bindservice，则oncreate()执行，onstart(int,bundle)不被调用；这种情况下绑定被解除，平台就可以清除该service(连接销毁后，会导致解除，解除后就会销毁)。
3. 被启动又被绑定
类似startservice的生命周期，oncreate onstart都会调用。
4. 停止服务时
stopservice时显式ondestroy()。或不再有绑定(没有启动时)时隐式调用。有bind情况下stopservice()不起作用。
以下是一个简单的实现例子，某些部分需要配合logcat观察。
acmain.java
package jtapp.myservicesamples;
import android.app.activity;
import android.content.componentname;
import android.content.context;
import android.content.intent;
import android.content.serviceconnection;
import android.os.bundle;
import android.os.ibinder;
import android.util.log;
import android.view.view;
import android.view.view.onclicklistener;
import android.widget.button;
import android.widget.toast;
public class acmain extends activity implements onclicklistener {
private static final string tag = "acmain";
private button btnstart;
private button btnstop;
private button btnbind;
private button btnexit;
/** called when the activity is first created. */
@override
public void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
findview();
}
private void findview() {
btnstart = (button) findviewbyid(r.id.start);
btnstop = (button) findviewbyid(r.id.stop);
btnbind = (button) findviewbyid(r.id.bind);
btnexit = (button) findviewbyid(r.id.exit);
btnstart.setonclicklistener(this);
btnstop.setonclicklistener(this);
btnbind.setonclicklistener(this);
btnexit.setonclicklistener(this);
}
@override
public void onclick(view v) {
intent intent = new intent("jtapp.myservicesamples.myservice");
switch(v.getid()) {
case r.id.start:
startservice(intent);
toast.maketext(this,
"myservice running " + myservice.msec/1000.0 + "s.",
toast.length_long).show();
break;
case r.id.stop:
stopservice(intent);
toast.maketext(this,
"myservice running " + myservice.msec/1000.0 + "s.",
toast.length_long).show();
break;
case r.id.bind:
bindservice(intent, sc, context.bind_auto_create);
break;
case r.id.exit:
this.finish();
break;
}
}
private myservice servicebinder;
private serviceconnection sc = new serviceconnection() {
@override
public void onservicedisconnected(componentname name) {
log.d(tag, "in onservicedisconnected");
servicebinder = null;
}
@override
public void onserviceconnected(componentname name, ibinder service) {
log.d(tag, "in onserviceconnected");
servicebinder = ((myservice.mybinder)service).getservice();
}
};
@override
protected void ondestroy() {
//this.unbindservice(sc);
//this.stopservice(
// new intent("jtapp.myservicesamples.myservice"));
super.ondestroy();
}
}
main.xml
<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<textview android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello" />
<button android:text="start myservice" android:id="@+id/start"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>
<button android:text="stop myservice" android:id="@+id/stop"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>
<button android:text="bind myservice" android:id="@+id/bind"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>
<button android:text="exit acmain" android:id="@+id/exit"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>
</linearlayout>
myservice.java
package jtapp.myservicesamples;
import android.app.service;
import android.content.intent;
import android.os.binder;
import android.os.ibinder;
import android.util.log;
public class myservice extends service {
private static final string tag = "myservice";
public static long msec = 0;
private boolean bthreadrunning = true;
private final ibinder binder = new mybinder();
public class mybinder extends binder {
myservice getservice() {
return myservice.this;
}
}
@override
public ibinder onbind(intent intent) {
return binder;
}
@override
public void oncreate() {
new thread(new runnable(){
@override
public void run() {
while (bthreadrunning) {
try {
thread.sleep(100);
} catch (interruptedexception e) {
}
log.i(tag, "myservice running " + (msec+=100) + "ms.");
}
}
}).start();
}
@override
public void ondestroy() {
bthreadrunning = false;
super.ondestroy(); // 可以不用
}
}
anndroidmanifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="jtapp.myservicesamples" android:versioncode="1"
android:versionname="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name"
android:debuggable="true">
<activity android:name=".acmain" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.main" />
<category android:name="android.intent.category.launcher" />
</intent-filter>
</activity>
<service android:name="myservice">
<intent-filter>
<action android:name="jtapp.myservicesamples.myservice"></action>
</intent-filter>
</service>
</application>
</manifest>
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