一、Service的简介

Service是Android中实现程序后台运行的解决方案，适用于去执行那些不需要和用户交互而且还要求长期运行的任务。Service是android 系统中的四大组件之一（Activity、Service、BroadcastReceiver、ContentProvider），它跟Activity的级别差不多，但不能自己运行只能后台运行，并且可以和其他组件进行交互。

讯享网
Service的分类如下

1、Service的生命周期 官方说明图

启动服务
生命周期为：onCreate->onStartCommand->onDestory
1.startService开启服务时，生命周期为
执行onCreate->onStartCommand(Android2.0之后用的都是这个,Android2.0以前是onStart)

stopService关闭服务时，执行onDestory

绑定服务

unbindSerivce解绑服务时，执行onUnBind->onDestory

1、首先创建MyService类继承Service

/ * 自定义本地服务 */ /* 1.startService() 第一次调用：-->构造方法()-->onCreate()-->onStartCommand() 后面再调用：-->onStartCommand() stopService():-->onDestroy() 2.bindService(Intent service, ServiceConnection conn,int flags) 第一次调用：-->构造方法()-->onCreate()-->onBind()-->onServiceConnected() unbindService(connection):-(只有当前Activity与Service连接)->onUnbind()-->onDestroy() */ public class MyService extends Service { 
    public MyService() { 
    Log.i("TAG", "MyService() "); } @Override public void onCreate() { 
    super.onCreate(); Log.i("TAG", "MyService onCreate() "); } @Override public int onStartCommand(Intent intent, int flags, int startId) { 
    Log.i("TAG", "MyService onStartCommand() "); return super.onStartCommand(intent, flags, startId); } @Override public void onDestroy() { 
    super.onDestroy(); Log.i("TAG", "MyService onDestroy() "); } @Nullable @Override public IBinder onBind(Intent intent) { 
    Log.i("TAG", "onBind() "); return new Binder(); } @Override public boolean onUnbind(Intent intent) { 
    Log.i("TAG", "onUnbind() "); return super.onUnbind(intent); } } 

2、在AndroidManifest.xml中进行注册

讯享网<service android:name=".local.MyService" /> 

3、ServiceActivity代码如下

public class ServiceActivity extends AppCompatActivity { 
    private ServiceConnection connection; @Override protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); setContentView(R.layout.activity_service); } //启动服务 public void startMyService(View view) { 
    Intent intent = new Intent(this, MyService.class); startService(intent); Toast.makeText(this, "启动服务！", Toast.LENGTH_SHORT).show(); } public void stopMyService(View view) { 
    Intent intent = new Intent(this, MyService.class); stopService(intent); Toast.makeText(this, "停止服务！", Toast.LENGTH_SHORT).show(); } //绑定服务 public void bindMyService(View view) { 
    Intent intent = new Intent(this, MyService.class); //创建连接对象 if (connection == null) { 
    connection = new ServiceConnection() { 
    //当与服务连接上之后，回调该方法 @Override public void onServiceConnected(ComponentName name, IBinder service) { 
    Log.i("TAG", "onServiceConnected()"); } //这个方法始终不会执行，不用管它 @Override public void onServiceDisconnected(ComponentName name) { 
    Log.i("TAG", "onServiceDisconnected()"); } }; //绑定service //BIND_AUTO_CREATE表示：创建之后自动绑定 bindService(intent, connection, BIND_AUTO_CREATE); Toast.makeText(this, "绑定服务！", Toast.LENGTH_SHORT).show(); } else { 
    Toast.makeText(this, "已经绑定服务！", Toast.LENGTH_SHORT).show(); } } //解绑服务 public void unBindMyService(View view) { 
    if (connection != null) { 
    unbindService(connection); connection = null; Toast.makeText(this, "解绑服务！", Toast.LENGTH_SHORT).show(); } else { 
    Toast.makeText(this, "还未进行绑定服务！", Toast.LENGTH_SHORT).show(); } } //当绑定服务后，不解绑服务直接退出，会有错误抛出，所以需要在 //当前Activity页面销毁的时候，执行解绑服务 @Override protected void onDestroy() { 
    super.onDestroy(); if (connection != null) { 
    unbindService(connection); connection = null; } } } 

二、远程服务AIDL的讲解

AIDL的理解

具体需求如下

具体步骤如下，首先写服务端应用

1、创建远程服务类MyRemoteService继承Service类

讯享网/ * 远程服务 */ public class MyRemoteService extends Service { 
    @Nullable @Override public IBinder onBind(Intent intent) { 
    Log.i("TAG", "onBind() "); return new StudentService(); } @Override public boolean onUnbind(Intent intent) { 
    Log.i("TAG", "onUnbind() "); return super.onUnbind(intent); } //处理Student相关的业务逻辑类 class StudentService extends IStudentService.Stub { 
    @Override public Student getStudentById(int id) throws RemoteException { 
    Log.i("TAG", "Service getStudentById() " + id); return new Student(id, "Tom", 10000); } } } 

2、在AndroidManifest.xml文件中注册该服务

 <service android:name=".local.MyRemoteService"> <intent-filter> <action android:name="local.MyRemoteService.Action" /> </intent-filter> </service> 

3、创建Student类，并实现Parcelable接口,传递对象

讯享网public class Student implements Parcelable { 
    private int id; private String name; private double price; public Student(int id, String name, double price) { 
    this.id = id; this.name = name; this.price = price; } protected Student(Parcel in) { 
    id = in.readInt(); name = in.readString(); price = in.readDouble(); } public static final Creator<Student> CREATOR = new Creator<Student>() { 
    @Override public Student createFromParcel(Parcel in) { 
    Log.i("TAG", "解包createFromParcel()"); return new Student(in); } //返回一个指定大小的对象容器 @Override public Student[] newArray(int size) { 
    return new Student[size]; } }; public int getId() { 
    return id; } public void setId(int id) { 
    this.id = id; } public String getName() { 
    return name; } public void setName(String name) { 
    this.name = name; } public double getPrice() { 
    return price; } public void setPrice(double price) { 
    this.price = price; } @Override public String toString() { 
    return "Student{" + "id=" + id + ", name='" + name + '\'' + ", price=" + price + '}'; } @Override public int describeContents() { 
    return 0; } @Override public void writeToParcel(Parcel dest, int flags) { 
    Log.i("TAG", "打包 writeToParcel() "); dest.writeInt(id); dest.writeString(name); dest.writeDouble(price); } } 

4、在src的main目录下，创建aidl文件默认会生成aidl文件夹。创建两个aidl文件，分别为

IStudentService.aidl

package com.example.customviewproject.entity; import com.example.customviewproject.entity.Student; interface IStudentService { 
    Student getStudentById(int id); } 

Student.aidl

讯享网// Student.aidl package com.example.customviewproject.entity; // Declare any non-default types here with import statements parcelable Student; 

AIDL的一些规则如下

服务端创建好后，客户端将服务端的aidl文件和Student类，原封不动的拷贝到客户端应用，意思就是说路径不要变。

客户端的界面如下

MainActivity中进行具体代码的编写，代码如下

public class MainActivity extends AppCompatActivity { 
    private EditText edit_id; private ServiceConnection connection; private IStudentService iStudentService; @Override protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); edit_id = findViewById(R.id.edit_id); } //绑定远端服务 public void bindRemoteService(View view) { 
    Intent intent = new Intent("local.MyRemoteService.Action"); intent.setPackage("com.example.customviewproject"); if (connection == null) { 
    connection = new ServiceConnection() { 
    @Override public void onServiceConnected(ComponentName componentName, IBinder iBinder) { 
    Log.i("TAG", "onServiceConnected() "); iStudentService = IStudentService.Stub.asInterface(iBinder); } @Override public void onServiceDisconnected(ComponentName componentName) { 
    } }; bindService(intent, connection, BIND_AUTO_CREATE); } else { 
    Toast.makeText(this, "已经绑定远端服务！", Toast.LENGTH_SHORT).show(); } } //调用远程服务端的方法 public void callRemoteMethod(View view) { 
    if (iStudentService != null) { 
    int id = Integer.parseInt(edit_id.getText().toString()); try { 
    Student student = iStudentService.getStudentById(id); Log.i("TAG", "callRemoteMethod() student.toString():" + student.toString()); } catch (RemoteException e) { 
    e.printStackTrace(); } } } //解绑远端服务 public void UnbindService(View view) { 
    if (connection != null) { 
    unbindService(connection); connection = null; iStudentService = null; Toast.makeText(this, "解绑远端服务！", Toast.LENGTH_SHORT).show(); } else { 
    Toast.makeText(this, "还未绑定远端服务！", Toast.LENGTH_SHORT).show(); } } } 

当用户首次进入后，点击绑定远端服务按钮执行的流程依次为

点击调用远程服务端的按钮，执行的流程依次为

点击解绑远程服务按钮，执行的流程依次为

以上是Service讲解，有什么不当之处，可在评论区指正共同学习!