1.Activity的生命周期状态(https://blog.csdn.net/ttandroid/article/details/80926753)
(1).ActivityA第一次启动，调用onCreate，onStart，onResume
(2).ActivityA启动到ActivityB的时候，A调用onPause，然后B调用onCreate, onStart, onResume,最后A在调用onStop(注意：如果A是透明的主题，A最后不会调用onStop)
(3).再次回到A时,B--->onPause,onStop,onDestory 然后A--->onRestart,onStart,onResume
(4).按Home键时，当前ActivityA--->onPause,onStop，长按home键再次回到 ActivityA时，onRestart,onStart,onResume
2.Fragment的生命周期状态(https://www.jianshu.com/p/c8f34229b6dc)
Fragment1切换到Fragment2时生命周期的变化
(1).通过add ,hide ,show 方式来切换Fragment
add-->fragemnt1周期变化-->onAttach --->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume
fragment1切换到fragment2--->fragment1周期不变化，会回调onHiddenChanged()方法
fragment2周期变化-->onAttach-->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume
fragment2再次回到fragment1时，不走任何周期性的方法但是会回调二者的onHiddenChanged()方法。
(2).通过replace的方法进行切换时：
repleace-->fragemnt1周期变化-->onAttach --->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume
fragment1切换到fragment2--->fragment1-->onPause-->onStop-->onDestoryView-->onDestory-->onDetach，fragment2-->onAttach-->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume
注意：通过repleace方法进行替换时，fragment都要重新new ,fragment都是进行了销毁，重建的过程，相当于走了一整套的生命周期。
(3).使用ViewPager进行切换时：
当使用ViewPager与Fragment进行切换时，fragment会进行预加载操作，所有的fragment都会提前初始化--预加载
加载fragment1-->onAttach-->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume同时预加载fragment2-->onAttach-->onCreate-->onCreateView-->onActivityCreated-->onStart-->onResume
当Fragment2切换到fragment1的时候，Fragment1，Fragment2不走任何生命周期方法，但是会回调
setUserVisiableHint()方法
3.Service的生命周期和二种启动方式(https://github.com/Asmewill/Genericity)
public class SimpleService extends Service {
public class LocalBinder extends Binder {
public SimpleService getService(){
return SimpleService.this;
}
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
System.out.println("onBind invoke");
return new LocalBinder();
}
@Override
public boolean onUnbind(Intent intent) {
System.out.println("onUnbind invoke");
return super.onUnbind(intent);
}
@Override
public void onCreate() {
System.out.println("onCreate invoke");
super.onCreate();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
System.out.println("onStartCommand invoke");
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
System.out.println("onDestroy invoke");
super.onDestroy();
}
}
serviceConnection=new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
System.out.println("onServiceConnected");
}
@Override
public void onServiceDisconnected(ComponentName name) {//取消绑定时，不会调用onServiceDisconnected
System.out.println("onServiceDisconnected");
}
};
注意，一个原则是Service的onCreate的方法只会被调用一次，就是你无论多少次的startService又bindService，Service只被创建一次，当客户端取消绑定时，系统“绝对不会”调用onServiceDisconnected方法。
(1). startService(it);---->onCreate -->onStartCommand 第二次startService-->onStartCommand
(2). stopService(it);---->onDestory
(3). bindService(it,serviceConnection,BIND_AUTO_CREATE)---->onCreate-->onBind
(4). unbindService(serviceConnection)--->onUnbind-->onDestory
4.Service之AIDL跨进程
、
(1).在AIDL中，并非支持所有数据类型，他支持的数据类型如下所示：
基本数据类型（int、long、char、boolean、double、float、byte、short）
String和CharSequence
List：只支持ArrayList，并且里面的每个元素必须被AIDL支持
Map： 只支持HashMap， 同样的，里面的元素都必须被AIDL支持，包括key和value
Parcelable：所有实现了Parcelable接口的对象
AIDL： 所有的AIDL接口本身也可以在AIDL 文件中使用
// BookManager.aidl
package com.lypeer.ipcclient;
import com.lypeer.ipcclient.Book;
interface BookManager {
//保证客户端与服务端是连接上的且数据传输正常
List getBooks();
//通过三种定位tag做对比试验，观察输出的结果
Book addBookIn(in Book book);
Book addBookOut(out Book book);
Book addBookInout(inout Book book);
String getString();
}
// Book.aidl
package com.lypeer.ipcclient;
parcelable Book;
(2).如果用到了自定义Parcelable对象，就需要创建一个同名的AIDL文件，包名要和实体类包名一致。
(3)服务端核心代码AIDLService.java
public class AIDLService extends Service {
public final String TAG = this.getClass().getSimpleName();
//包含Book对象的list
private List mBooks = new ArrayList<>();
//由AIDL文件生成的BookManager
private final BookManager.Stub mBookManager = new BookManager.Stub() {
@Override
public List getBooks() throws RemoteException {
synchronized (this) {
Log.i(TAG, "invoking getBooks() method , now the list is : " + mBooks.toString());
if (mBooks != null) {
return mBooks;
}
return new ArrayList<>();
}
}
@Override
public Book addBookIn(Book book) throws RemoteException {
synchronized (this) {
if (mBooks == null) {
mBooks = new ArrayList<>();
}
if(book == null){
Log.e(TAG , "Book is null in In");
book = new Book();
}
//尝试修改book的参数，主要是为了观察其到客户端的反馈
book.setPrice(2333);
if (!mBooks.contains(book)) {
mBooks.add(book);
}
//打印mBooks列表，观察客户端传过来的值
Log.i(TAG, "invoking addBookIn() method , now the list is : " + mBooks.toString());
return book;
}
}
@Override
public Book addBookOut(Book book) throws RemoteException {
synchronized (this) {
if (mBooks == null) {
mBooks = new ArrayList<>();
}
if(book == null){
Log.e(TAG , "Book is null in Out");
book = new Book();
}
book.setPrice(2333);
if (!mBooks.contains(book)) {
mBooks.add(book);
}
Log.e(TAG, "invoking addBookOut() method , now the list is : " + mBooks.toString());
return book;
}
}
@Override
public Book addBookInout(Book book) throws RemoteException {
synchronized (this) {
if (mBooks == null) {
mBooks = new ArrayList<>();
}
if(book == null){
Log.e(TAG , "Book is null in Inout");
book = new Book();
}
book.setPrice(2333);
if (!mBooks.contains(book)) {
mBooks.add(book);
}
Log.i(TAG, "invoking addBookInout() method , now the list is : " + mBooks.toString());
return book;
}
}
@Override
public String getString() throws RemoteException {
return "aaaa";
}
};
@Override
public void onCreate() {
Book book = new Book();
book.setName("Android开发艺术探索");
book.setPrice(28);
mBooks.add(book);
super.onCreate();
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
Log.i(getClass().getSimpleName(), String.format("on bind,intent = %s", intent.toString()));
return mBookManager;
}
}
(4).客户端核心代码
public class AIDLActivity extends AppCompatActivity {
//由AIDL文件生成的Java类
private BookManager mBookManager = null;
//标志当前与服务端连接状况的布尔值，false为未连接，true为连接中
private boolean mBound = false;
//包含Book对象的list
private List mBooks;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_aidl);
}
/**
* 按钮的点击事件，点击之后调用服务端的addBookIn方法
*
* @param view
*/
public void addBook(View view) {
//如果与服务端的连接处于未连接状态，则尝试连接
if (!mBound) {
attemptToBindService();
Toast.makeText(this, "当前与服务端处于未连接状态，正在尝试重连，请稍后再试", Toast.LENGTH_SHORT).show();
return;
}
if (mBookManager == null) return;
Book book = new Book();
book.setName("APP研发录In");
book.setPrice(30);
try {
mBookManager.addBookIn(book);
Log.i(getLocalClassName(), "客户端获取BookList:"+mBookManager.getBooks().toString()+"----获取String："+mBookManager.getString());
} catch (RemoteException e) {
e.printStackTrace();
}
}
/**
* 尝试与服务端建立连接
*/
private void attemptToBindService() {
Intent intent = new Intent();
intent.setAction("com.lypeer.aidl");
intent.setPackage("com.lypeer.ipcserver");
bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
}
@Override
protected void onStart() {
super.onStart();
if (!mBound) {
attemptToBindService();
}
}
@Override
protected void onStop() {
super.onStop();
if (mBound) {
unbindService(mServiceConnection);
mBound = false;
}
}
private ServiceConnection mServiceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Log.e(getLocalClassName(), "service connected");
mBookManager = BookManager.Stub.asInterface(service);
mBound = true;
if (mBookManager != null) {
try {
mBooks = mBookManager.getBooks();
Log.e(getLocalClassName(), mBooks.toString());
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
@Override
public void onServiceDisconnected(ComponentName name) {
Log.e(getLocalClassName(), "service disconnected");
mBound = false;
}
};
}
5.BraodCastReceiver详解
(1).常驻型广播-->静态注册
(2).非驻型广播-->动态注册
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(String); //为BroadcastReceiver指定action，使之用于接收同action的广播
registerReceiver(BroadcastReceiver,intentFilter);
注意：一般动态注册的广播，已经要在onPause或者onDestory中予以 unregisterReceiver(rhelper),否则容易造成内存泄漏。
6.ContentProvider详解
https://www.jianshu.com/p/5e13d1fec9c9