Activity#startActivity
//從Activity的startActivity方法爲起點分析
//Activity#startActivity方法
public void startActivity(Intent intent, @Nullable Bundle options)
{
if (options != null) {
startActivityForResult(intent, -1, options);
} else {
// Note we want to go through this call for compatibility with
// applications that may have overridden the method.
startActivityForResult(intent, -1);
}
}
//Activity#startActivityForResult方法
public void startActivityForResult(Intent intent, int requestCode, @Nullable Bundle options)
{
if (mParent == null) {
Instrumentation.ActivityResult ar =
//調用Instrumentation的execStartActivity方法 mInstrumentation 是在ActivtyThread attach方法時候創建的實例
mInstrumentation.execStartActivity(
this, mMainThread.getApplicationThread(), mToken, this,
intent, requestCode, options);
...
}
}
Instrumentation#execStartActivity
//Instrumentation 的 execStartActivity方法
public ActivityResult execStartActivity(
Context who, IBinder contextThread, IBinder token, Activity target,
Intent intent, int requestCode, Bundle options)
{
try {
intent.migrateExtraStreamToClipData();
intent.prepareToLeaveProcess();
//調用ActivityManagerNative 的getDefault 獲取單例，調用的startActivity方法
int result = ActivityManagerNative.getDefault()
.startActivity(whoThread, who.getBasePackageName(), intent,
intent.resolveTypeIfNeeded(who.getContentResolver()),
token, target != null ? target.mEmbeddedID : null,
requestCode, 0, null, options);
checkStartActivityResult(result, intent);
} catch (RemoteException e) {
}
return null;
}
ActivityManagerNative#getDefault
//獲取單例
static public IActivityManager getDefault()
{
return gDefault.get();
}
//查看單例方法
private static final Singleton<IActivityManager> gDefault = new Singleton<IActivityManager>()
{
protected IActivityManager create() {
//獲取binder的activity服務
IBinder b = ServiceManager.getService("activity");
if (false) {
Log.v("ActivityManager", "default service binder = " + b);
}
//通過asInterface獲取IActivityManager
IActivityManager am = asInterface(b);
if (false) {
Log.v("ActivityManager", "default service = " + am);
}
return am;
}
};
//asInterface
static public IActivityManager asInterface(IBinder obj)
{
if (obj == null) {
return null;
}
//查詢本地是否存在IActivityManager接口，如果存在直接返回
IActivityManager in =
(IActivityManager)obj.queryLocalInterface(descriptor);
if (in != null) {
return in;
}
//沒有，則創建一個ActivityManagerProxy 實例
return new ActivityManagerProxy(obj);
}
ActivityManagerProxy
//ActivityManagerProxy是ActivityManagerNative的一個內部類 所以剛纔ActivityManagerNative.getDefault()
// .startActivity 實際上調用的是ActivityManagerProxy的startActivity
class ActivityManagerProxy implements IActivityManager
{
public ActivityManagerProxy(IBinder remote)
{
mRemote = remote;
}
public IBinder asBinder()
{
return mRemote;
}
//startActivity 從此方法看出，一個binder通信的Client端
public int startActivity(IApplicationThread caller, String callingPackage, Intent intent,
String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options) throws RemoteException {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeInterfaceToken(IActivityManager.descriptor);
data.writeStrongBinder(caller != null ? caller.asBinder() : null);
data.writeString(callingPackage);
intent.writeToParcel(data, 0);
data.writeString(resolvedType);
data.writeStrongBinder(resultTo);
data.writeString(resultWho);
data.writeInt(requestCode);
data.writeInt(startFlags);
if (profilerInfo != null) {
data.writeInt(1);
profilerInfo.writeToParcel(data, Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
} else {
data.writeInt(0);
}
if (options != null) {
data.writeInt(1);
options.writeToParcel(data, 0);
} else {
data.writeInt(0);
}
//通過下面的transact方法的定義START_ACTIVITY_TRANSACTION是一個特徵Code，通過START_ACTIVITY_TRANSACTION我們可以找到他的服務端
mRemote.transact(START_ACTIVITY_TRANSACTION, data, reply, 0);
reply.readException();
int result = reply.readInt();
reply.recycle();
data.recycle();
return result;
}
/**
* Perform a generic operation with the object.
*
* @param code The action to perform. This should
* be a number between {@link #FIRST_CALL_TRANSACTION} and
* {@link #LAST_CALL_TRANSACTION}.
* @param data Marshalled data to send to the target. Must not be null.
* If you are not sending any data, you must create an empty Parcel
* that is given here.
* @param reply Marshalled data to be received from the target. May be
* null if you are not interested in the return value.
* @param flags Additional operation flags. Either 0 for a normal
* RPC, or {@link #FLAG_ONEWAY} for a one-way RPC.
*/
/*public boolean transact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException;*/
public int startActivityAsUser(IApplicationThread caller, String callingPackage, Intent intent,
String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options,
int userId) throws RemoteException {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeInterfaceToken(IActivityManager.descriptor);
data.writeStrongBinder(caller != null ? caller.asBinder() : null);
data.writeString(callingPackage);
intent.writeToParcel(data, 0);
data.writeString(resolvedType);
data.writeStrongBinder(resultTo);
data.writeString(resultWho);
data.writeInt(requestCode);
data.writeInt(startFlags);
if (profilerInfo != null) {
data.writeInt(1);
profilerInfo.writeToParcel(data, Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
} else {
data.writeInt(0);
}
if (options != null) {
data.writeInt(1);
options.writeToParcel(data, 0);
} else {
data.writeInt(0);
}
data.writeInt(userId);
mRemote.transact(START_ACTIVITY_AS_USER_TRANSACTION, data, reply, 0);
reply.readException();
int result = reply.readInt();
reply.recycle();
data.recycle();
return result;
}
...
}
Binder服務端 ActivityManagerNative
//通過AcitivityManagerProxy的startActivityAsUser 發送Binder請求
//ActivityManagerNative de onTransact 進行接受 調用自己的startActivity方法
//這裏實質上是ActivityManagerService的接受 ActivityManagerService繼承ActivityManagerNative
@Override
public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException {
switch (code) {
case START_ACTIVITY_TRANSACTION: {
data.enforceInterface(IActivityManager.descriptor);
IBinder b = data.readStrongBinder();
IApplicationThread app = ApplicationThreadNative.asInterface(b);
String callingPackage = data.readString();
Intent intent = Intent.CREATOR.createFromParcel(data);
String resolvedType = data.readString();
IBinder resultTo = data.readStrongBinder();
String resultWho = data.readString();
int requestCode = data.readInt();
int startFlags = data.readInt();
ProfilerInfo profilerInfo = data.readInt() != 0
? ProfilerInfo.CREATOR.createFromParcel(data) : null;
Bundle options = data.readInt() != 0
? Bundle.CREATOR.createFromParcel(data) : null;
int result = startActivity(app, callingPackage, intent, resolvedType,
resultTo, resultWho, requestCode, startFlags, profilerInfo, options);
reply.writeNoException();
reply.writeInt(result);
return true;
}
...
}
//startActivity方法
@Override
public final int startActivity(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options){
return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,
resultWho, requestCode, startFlags, profilerInfo, options,
UserHandle.getCallingUserId());
}
//startActivityAsUser方法
@Override
public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle options, int userId){
enforceNotIsolatedCaller("startActivity");
userId = handleIncomingUser(Binder.getCallingPid(), Binder.getCallingUid(), userId,
false, ALLOW_FULL_ONLY, "startActivity", null);
// TODO: Switch to user app stacks here.
//調用ActivityStackSupervisor的startActivityMayWait方法
return mStackSupervisor.startActivityMayWait(caller, -1, callingPackage, intent,
resolvedType, null, null, resultTo, resultWho, requestCode, startFlags,
profilerInfo, null, null, options, userId, null, null);
}
ActivityStackSupervisor#startActivityMayWait
//startActivityMayWait
public void startActivityMayWait(){
...
int res = startActivityLocked(caller, intent, resolvedType, aInfo,
voiceSession, voiceInteractor, resultTo, resultWho,
requestCode, callingPid, callingUid, callingPackage,
realCallingPid, realCallingUid, startFlags, options,
componentSpecified, null, container, inTask);
....
}
//startActivityLocked
public void startActivityLocked()
{
...
resumeTopActivitiesLocked(targetStack, null, options);
...
}
//resumeTopActivitiesLocked
boolean resumeTopActivitiesLocked(ActivityStack targetStack, ActivityRecord target,
Bundle targetOptions)
{
if (targetStack == null) {
targetStack = getFocusedStack();
}
// Do targetStack first.
boolean result = false;
if (isFrontStack(targetStack)) {
//resume 棧頂 Activity
result = targetStack.resumeTopActivityLocked(target, targetOptions);
}
for (int displayNdx = mActivityDisplays.size() - 1; displayNdx >= 0; --displayNdx) {
final ArrayList<ActivityStack> stacks = mActivityDisplays.valueAt(displayNdx).mStacks;
for (int stackNdx = stacks.size() - 1; stackNdx >= 0; --stackNdx) {
final ActivityStack stack = stacks.get(stackNdx);
if (stack == targetStack) {
// Already started above.
continue;
}
if (isFrontStack(stack)) {
stack.resumeTopActivityLocked(null);
}
}
}
return result;
}
ActivityStack#resumeTopActivityLocked
//resumeTopActivityLocked
final boolean resumeTopActivityLocked(ActivityRecord prev, Bundle options)
{
if (mStackSupervisor.inResumeTopActivity) {
// Don't even start recursing.
return false;
}
boolean result = false;
try {
// Protect against recursion.
mStackSupervisor.inResumeTopActivity = true;
if (mService.mLockScreenShown == ActivityManagerService.LOCK_SCREEN_LEAVING) {
mService.mLockScreenShown = ActivityManagerService.LOCK_SCREEN_HIDDEN;
mService.updateSleepIfNeededLocked();
}
result = resumeTopActivityInnerLocked(prev, options);
}
finally {
mStackSupervisor.inResumeTopActivity = false;
}
return result;
}
//resumeTopActivityInnerLocked
public void resumeTopActivityInnerLocked(){
....
//調用startSpecificActivityLocked 這裏進行熱啓動 冷啓動的區分調用了
mStackSupervisor.startSpecificActivityLocked(next, true, true);
...
}
//startSpecificActivityLocked 這裏進行熱啓動 冷啓動的區分調用了進入AMS的調用進程開啓新的App下半段了
void startSpecificActivityLocked(ActivityRecord r,
boolean andResume, boolean checkConfig)
{
// Is this activity's application already running?
ProcessRecord app = mService.getProcessRecordLocked(r.processName,
r.info.applicationInfo.uid, true);
r.task.stack.setLaunchTime(r);
if (app != null && app.thread != null) {
try {
if ((r.info.flags&ActivityInfo.FLAG_MULTIPROCESS) == 0
|| !"android".equals(r.info.packageName)) {
// Don't add this if it is a platform component that is marked
// to run in multiple processes, because this is actually
// part of the framework so doesn't make sense to track as a
// separate apk in the process.
app.addPackage(r.info.packageName, r.info.applicationInfo.versionCode,
mService.mProcessStats);
}
realStartActivityLocked(r, app, andResume, checkConfig);
return;
} catch (RemoteException e) {
Slog.w(TAG, "Exception when starting activity "
+ r.intent.getComponent().flattenToShortString(), e);
}
// If a dead object exception was thrown -- fall through to
// restart the application.
}
mService.startProcessLocked(r.processName, r.info.applicationInfo, true, 0,
"activity", r.intent.getComponent(), false, false, true);
}