参考:http://www.jianshu.com/p/2fb6eb14fdec
http://www.cnblogs.com/codingblock/p/4850299.html
http://www.jianshu.com/p/b441d41272af
Service的基本用法
1、基本介绍
Service是Android四大组件之一,是可执行的程序,也有自己的生命周期,创建、配置Service和创建、配置Activity的过程相似
2、Service两种启动方式
(1)采用startService(Intent)方法
使用步骤:
- 定义一个类继承Service
- 在Mainfest.xml文件中配置Service
- 使用Context的startService(Intent)方法启动service
不再使用时,调用stopService(Intent)方法停止改服务
使用这种start方式启动的Service的生命周期如下:
onCreate→onStartCommand→onDestory
注:如果服务已经开始,不会重复的执行onCreate(),只会执行onStartCommand(),服务停止的时候调用onDestory(),服务只会被停止一次
特点:一旦服务开启调用者和被调用服务没有任何关系,开启着退出,服务仍然在后台运行
(2)采用bind方式开启
使用步骤:
- 定义一个类继承Service
- 在Mainfest.xml文件中配置Service
- 使用Context的bindService(Intent,ServicConnection,int)方法启动Service
不再使用时,调用unbindService(ServiceConnection)方法停止该服务
使用这种开启方式的Service的生命周期:
onCreate()→onBind()→onunbind()→onDestory()
特点:服务和开启者绑定在一起
服务与Activity之间的通信
1、Activity传递给Service
(1)使用Intent:在开启服务时通过将数据放置到Intent中,传递给Service
MainActivity
(2)先在Service中新建一个内部类Binder并继承Binder,这个类中包含两个方法,一个是获得Service对象的getService用于传给Activity,另一个方法就是设置Service中的成员变量的方法,在MainActivity中首先添加一个Binder变量binder,并且在onServiceConnected(ComponentName name,IBinder service)方法中获得从Service传递过来的IBinder类型的service并赋值给binder,最后这个binder就可以调用setData()方法把值传递给Service喽,具体看代码,因为这两种方法比较简单,我都放到一起写了:
MainActivity
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private TextView tv_out;
private EditText et_data;
private Button btn_start,btn_stop,btn_bind,btn_unbind,btn_sync;
private Intent intent=null;
MyServiceConn myserviceConn=null;
MyService.MyBinder binder=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
intent=new Intent(MainActivity.this,MyService.class);
myserviceConn=new MyServiceConn();
init();
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btn_start_service:
//通过Intent传递
intent.putExtra("data", "activityToService");
startService(intent);
break;
case R.id.btn_stop_service:
stopService(intent);
break;
case R.id.btn_bind_service:
bindService(intent,myserviceConn, Context.BIND_AUTO_CREATE);
break;
case R.id.btn_unbind_service:
if(binder!=null){
unbindService(myserviceConn);
}
break;
case R.id.btn_sync_data:
//Log.d("binder_async","binder_async");
if(binder!=null)
{
// Log.d("async","async");
//当检测到binder不为空时,就调用setData()方法传递
binder.setData("ni hao");
}
break;
default:break;
}
}
private void init(){
tv_out= (TextView) findViewById(R.id.tv_out);
et_data= (EditText) findViewById(R.id.et_data);
btn_start= (Button) findViewById(R.id.btn_start_service);
btn_stop= (Button) findViewById(R.id.btn_stop_service);
btn_bind= (Button) findViewById(R.id.btn_bind_service);
btn_unbind= (Button) findViewById(R.id.btn_unbind_service);
btn_sync= (Button) findViewById(R.id.btn_sync_data);
listen();
}
private void listen(){
btn_start.setOnClickListener(this);
btn_stop.setOnClickListener(this);
btn_bind.setOnClickListener(this);
btn_unbind.setOnClickListener(this);
btn_sync.setOnClickListener(this);
}
class MyServiceConn implements ServiceConnection {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
binder=(MyService.MyBinder)service;
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
}
}
MyService代码
public class MyService extends Service {
private String fromActivitydata_intent="";
private String fromActivitydata_setData="";
private Boolean serviceIsRunning=false;
@Nullable
@Override
public IBinder onBind(Intent intent) {
System.out.println("===onBind()===");
return new MyBinder();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
fromActivitydata_intent=intent.getStringExtra("data");
System.out.println("===onStartCommand()===");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onCreate() {
super.onCreate();
serviceIsRunning=true;
System.out.println("===onCreate()===");
new Thread(){
@Override
public void run() {
while(serviceIsRunning)
{
System.out.println("setData:"+fromActivitydata_setData);
System.out.println("intent:"+fromActivitydata_intent);
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
}
@Override
public boolean onUnbind(Intent intent) {
System.out.println("===onUnbind()===");
return super.onUnbind(intent);
}
@Override
public void onDestroy() {
serviceIsRunning=false;
System.out.println("===onDestory()===");
super.onDestroy();
}
//这里定义两个方法,一个用于返回MyService对象,一个用于获得Activity传递过来的数据
class MyBinder extends Binder {
public MyService getService(){
return MyService.this;
}
public void setData(String str){
fromActivitydata_setData=str;
}
}
}
运行结果:
初始界面:
当点击startservice时,logcat显示如下:
可以看出此时可以Service接收到MainActivity通过Intent传递过来的数据
点击bindservice时,显示如下:
这个时候也可以接收到通过setData()方法传递过来的数据啦
2、Service传递给Activity
首先在Service中新建一个接口
public interface DataCallback{
void getServiceData(String str);
}
其次在Service中新建一个DataCallback变量,并设置set,get方法:
DataCallback dataCallback=null;
public DataCallback getDataCallback() {
return dataCallback;
}
public void setDataCallback(DataCallback dataCallback) {
this.dataCallback = dataCallback;
}
在Service中需要获取值的地方调用接口方法:
if(dataCallback!=null){
dataCallback.getServiceData(str);
}
在Activity的onServiceConnected()方法中获得Service对象,并且初始化DataCallback:
public void onServiceConnected(ComponentName name, IBinder service) {
binder= (MyService.MyBinder) service;
binder.getService().setDataCallback(new MyService.DataCallback(){
//这里进行传递数据
}
具体代码如下:
MyService:
public class MyService extends Service {
private boolean isServiceRunning=false;
private String activityData="";
@Nullable
@Override
public IBinder onBind(Intent intent) {
System.out.println("===onBind()===");
return new MyBinder();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
System.out.println("===onStartCommand()===");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onCreate() {
super.onCreate();
System.out.println("===onCreate()===");
isServiceRunning=true;
new Thread(){
@Override
public void run() {
int n=0;
while(isServiceRunning){
n++;
String str=n+activityData;
System.out.println(str);
if(dataCallback!=null){
dataCallback.getServiceData(str);
}
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
}
public class MyBinder extends Binder {
public MyService getService(){
return MyService.this;
}
public void getActivityData(String str){
activityData=str;
}
}
DataCallback dataCallback=null;
public DataCallback getDataCallback() {
return dataCallback;
}
public void setDataCallback(DataCallback dataCallback) {
this.dataCallback = dataCallback;
}
@Override
public boolean onUnbind(Intent intent) {
System.out.println("===onUnbind()===");
return super.onUnbind(intent);
}
@Override
public void onDestroy() {
super.onDestroy();
System.out.println("===onDestory()===");
isServiceRunning=false;
}
public interface DataCallback{
void getServiceData(String str);
}
}
MainActivity
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private TextView tv;
private EditText et;
private Button start,stop,bind,unbind,syncData;
private Intent intent=null;
MyService.MyBinder binder=null;
MyServiceConn myServiceConn=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
intent=new Intent(MainActivity.this, MyService.class);
myServiceConn=new MyServiceConn();
init();
}
@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.btn_start_service:
startService(intent);
break;
case R.id.btn_stop_service:
stopService(intent);
break;
case R.id.btn_bind_service:
bindService(intent,myServiceConn, Context.BIND_AUTO_CREATE);
break;
case R.id.btn_unbind_service:
if(binder!=null){
unbindService(myServiceConn);
}
break;
case R.id.btn_sync_data:
System.out.println("sync");
if(binder!=null){
binder.getActivityData(et.getText().toString());
}
break;
default:break;
}
}
public void init(){
tv= (TextView) findViewById(R.id.tv_out);
et= (EditText) findViewById(R.id.et_data);
start= (Button) findViewById(R.id.btn_start_service);
stop= (Button) findViewById(R.id.btn_stop_service);
bind= (Button) findViewById(R.id.btn_bind_service);
unbind= (Button) findViewById(R.id.btn_unbind_service);
syncData= (Button) findViewById(R.id.btn_sync_data);
clickListener();
}
public void clickListener(){
start.setOnClickListener(this);
stop.setOnClickListener(this);
bind.setOnClickListener(this);
unbind.setOnClickListener(this);
syncData.setOnClickListener(this);
}
class MyServiceConn implements ServiceConnection {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
binder= (MyService.MyBinder) service;
binder.getService().setDataCallback(new MyService.DataCallback(){
@Override
public void getServiceData(String str) {
Message msg=new Message();
Bundle bundle=new Bundle();
bundle.putString("str",str);
msg.setData(bundle);
handler.sendMessage(msg);
}
Handler handler=new Handler(){
public void handleMessage(android.os.Message msg) {
tv.setText(msg.getData().getString("str"));
}
};
});
}
@Override
public void onServiceDisconnected(ComponentName name) {
binder=null;
}
}
}
运行结果:
初始时界面是这样:
输入你好,点击StartService:
logcat显示如下:
此时service与actiivty还没传递数据
点击bindservice,logcat显示如下:
接着点击同步数据:
UI显示:
发现activity传递给service的数据也已经接收,并且service把这个数据传回了activity用textview显示了