一、android 中进程间通信常用的有以下几种机制
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名称 优点 缺点 适用场景
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Bundle 简单易用 只能传输Bundle支持的数据类型 四大组件间的进程通信
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文件共享 简单易用 不适合高并发场景，并且无法做到 无并发访问情形，交换简单
进程间及时通信 的数据实时性不高的场景
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AIDL 功能强大，支持一对多并发 使用稍复杂，需要处理好线程同步 一对多通信且有RPC需求
通信，支持实时通信
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Messenger 功能一般，支持一对多串行 不能很好处理高并发情形，不支持 低并发的一对多即时通
通信，支持实时通信 RPC， 数据通过Message进行传输 信，无RPC需求 或者无需
只能传输Bundle支持的数据 类型 返回结果的RPC需求
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ContentProvider 在数据源访问页面功能强大， 可以理解为受约束的AIDL， 一对多的进程间的数据共享
支持一对多并发数据共享， 主要提 供数据源的CRUD操作
可通过Call方法扩展其他操作
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Socket 功能强大，可以通过网络数 实现细节有点繁琐 网络数据交换
字传输 节流，支持一对多 ，不支持直接的RPC
并发实时通信
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二、 Bundle
Bundle实现了Parcelable接口，所以可以方便的在不同进程间传输，当在一个进程中启动了另外一个进程的Activity、Service、Receiver，可以在Bundle中附加需要传输给远程进程的信息并通过Intent发送出去。
三、文件共享
Activity1：-----------------
private void persistToFile() {
new Thread(new Runnable() {
@Override
public void run() {
User user = new User(1, "hello world", false);
File dir = new File(MyConstants.CHAPTER_2_PATH);
if (!dir.exists()) {
dir.mkdirs();
}
File cachedFile = new File(MyConstants.CACHE_FILE_PATH);
ObjectOutputStream objectOutputStream = null;
try {
objectOutputStream = new ObjectOutputStream(
new FileOutputStream(cachedFile));
objectOutputStream.writeObject(user);//利用Serializable序列化的过程
Log.d(TAG, "persist user:" + user);
} catch (IOException e) {
e.printStackTrace();
} finally {
MyUtils.close(objectOutputStream);
}
}
}).start();
}
Activity2:----------------
private void recoverFromFile() {
new Thread(new Runnable() {
@Override
public void run() {
User user = null;
File cachedFile = new File(MyConstants.CACHE_FILE_PATH);
if (cachedFile.exists()) {
//对MainActivity中user对象反序列化的过程(Serializable),
//得到的是一个新的对象
ObjectInputStream objectInputStream = null;
try {
objectInputStream = new ObjectInputStream(
new FileInputStream(cachedFile));
user = (User) objectInputStream.readObject();
Log.d(TAG, "recover user:" + user);
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} finally {
MyUtils.close(objectInputStream);
}
}
}
}).start();
}
四、Messenger
4.1 server端
public class MessengerService extends Service {
private static final String TAG = "MessengerService";
private static class MessengerHandler extends Handler {//1.创建一个Handler
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MyConstants.MSG_FROM_CLIENT:
Log.i(TAG, "receive msg from Client:" + msg.getData().getString("msg"));
Messenger client = msg.replyTo;//这里是：客户端接收服务端的Messenger
Message relpyMessage = Message.obtain(null, MyConstants.MSG_FROM_SERVICE);
Bundle bundle = new Bundle();
bundle.putString("reply", "嗯，你的消息我已经收到，稍后会回复你。");
relpyMessage.setData(bundle);
try {
client.send(relpyMessage);//<-----
} catch (RemoteException e) {
e.printStackTrace();
}
break;
default:
super.handleMessage(msg);
}
}
}
//2.通过handlercg创建一个Messenger对象
private final Messenger mMessenger = new Messenger(new MessengerHandler());
@Override
public IBinder onBind(Intent intent) {
return mMessenger.getBinder();//返回底层的Binder
}
4.2 Client端
public class MessengerActivity extends Activity {
private static final String TAG = "MessengerActivity";
private Messenger mService;
private Messenger mGetReplyMessenger = new Messenger(new MessengerHandler());
private static class MessengerHandler extends Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MyConstants.MSG_FROM_SERVICE:
Log.i(TAG, "receive msg from Service:" + msg.getData().getString("reply"));
break;
default:
super.handleMessage(msg);
}
}
}
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
mService = new Messenger(service);//服务端接收客户端的Messenger
Log.d(TAG, "bind service");
Message msg = Message.obtain(null, MyConstants.MSG_FROM_CLIENT);
Bundle data = new Bundle();
data.putString("msg", "hello, this is client.");
msg.setData(data);
msg.replyTo = mGetReplyMessenger;//客户端接收服务端的Messenger
try {
mService.send(msg);//<-----
} catch (RemoteException e) {
e.printStackTrace();
}
}
public void onServiceDisconnected(ComponentName className) {
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_messenger);
Intent intent = new Intent("com.ryg.MessengerService.launch");
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);//1.绑定service
}
@Override
protected void onDestroy() {
unbindService(mConnection);
super.onDestroy();
}
}
五、AIDL
5.1远端service实现
AIDL接口实现：
//IBookManager.aidl
interface IBookManager {
//声明暴露给客户端的接口
List<Book> getBookList();
void addBook(in Book book);
}
public class BookManagerService extends Service {//1.创建service用来监听客户端连接请求
private static final String TAG = "BMS";
private AtomicBoolean mIsServiceDestoryed = new AtomicBoolean(false);
private CopyOnWriteArrayList<Book> mBookList = new CopyOnWriteArrayList<Book>();
private Binder mBinder = new IBookManager.Stub() {//实现aidl接口
@Override
public List<Book> getBookList() throws RemoteException {
return mBookList;
}
@Override
public void addBook(Book book) throws RemoteException {
mBookList.add(book);
}
@Override
public void onCreate() {
super.onCreate();
mBookList.add(new Book(1, "Android"));
mBookList.add(new Book(2, "Ios"));
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
}
5.2 客户端实现(简单理解篇，可能有ANR)
public class BookManagerActivity extends Activity {
private static final String TAG = "BookManagerActivity";
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
IBookManager bookManager = IBookManager.Stub.asInterface(service);
try {
List<Book> list = bookManager.getBookList();
Log.i(TAG, "query book list, list type:"
+ list.getClass().getCanonicalName());
Log.i(TAG, "query book list:" + list.toString());
} catch (RemoteException e) {
e.printStackTrace();
}
}
public void onServiceDisconnected(ComponentName className) {
}
};
private IOnNewBookArrivedListener mOnNewBookArrivedListener = new IOnNewBookArrivedListener.Stub() {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_book_manager);
Intent intent = new Intent(this, BookManagerService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);//1.绑定服务
}
@Override
protected void onDestroy() {
unbindService(mConnection);
super.onDestroy();
}
}