- FLAG_GRANT_READ_URI_PERMISSION
/**
* If set, the recipient of this Intent will be granted permission to
* perform read operations on the URI in the Intent's data and any URIs
* specified in its ClipData. When applying to an Intent's ClipData,
* all URIs as well as recursive traversals through data or other ClipData
* in Intent items will be granted; only the grant flags of the top-level
* Intent are used.
*/
临时访问读权限 intent的接受者将被授予 INTENT 数据uri 或者 在ClipData 上的读权限。
- FLAG_GRANT_WRITE_URI_PERMISSION
/**
* If set, the recipient of this Intent will be granted permission to
* perform write operations on the URI in the Intent's data and any URIs
* specified in its ClipData. When applying to an Intent's ClipData,
* all URIs as well as recursive traversals through data or other ClipData
* in Intent items will be granted; only the grant flags of the top-level
* Intent are used.
*/ 临时访问写权限 intent的接受者将被授予 INTENT 数据uri 或者 在ClipData 上的写权限。
3.FLAG_FROM_BACKGROUND
/**
* Can be set by the caller to indicate that this Intent is coming from
* a background operation, not from direct user interaction.
*/ 指明Intent来自后台操作 ，不是来自用户直接互动。
4.FLAG_DEBUG_LOG_RESOLUTION
/**
* A flag you can enable for debugging: when set, log messages will be
* printed during the resolution of this intent to show you what has
* been found to create the final resolved list.
*/解析intent时打印log messages，展示创建最终的resolved list 找到的信息 。
比如有如下代码 ：
Intent intent = new Intent("android.provider.Telephony.SMS_RECEIVED");
intent.addFlags(Intent.FLAG_DEBUG_LOG_RESOLUTION);
sendBroadcast(intent);
将会按照优先级打印出系统所有注册"android.provider.Telephony.SMS_RECEIVED"的广播接收者。
5.FLAG_EXCLUDE_STOPPED_PACKAGES
/**
* If set, this intent will not match any components in packages that
* are currently stopped. If this is not set, then the default behavior
* is to include such applications in the result.
*/如果设置 intent 将不会匹配处于stoped状态的组件，如果没设置，默认匹配 。
6.FLAG_INCLUDE_STOPPED_PACKAGES
/**
* If set, this intent will always match any components in packages that
* are currently stopped. This is the default behavior when
* {@link #FLAG_EXCLUDE_STOPPED_PACKAGES} is not set. If both of these
* flags are set, this one wins (it allows overriding of exclude for
* places where the framework may automatically set the exclude flag).
*/ 如果设置，intent将匹配packages 内stopped状态的组件，也是intent的默认设置， 如果 exclude 跟 include 同时设置 ，include win！
- FLAG_GRANT_PERSISTABLE_URI_PERMISSION
/**
* When combined with FLAG_GRANT_READ_URI_PERMISSION and/or
* FLAG_GRANT_WRITE_URI_PERMISSION, the URI permission grant can be
* persisted across device reboots until explicitly revoked with
* {@link Context#revokeUriPermission(Uri, int)}. This flag only offers the
* grant for possible persisting; the receiving application must call
* {@link ContentResolver#takePersistableUriPermission(Uri, int)} to
* actually persist.
*
* @see ContentResolver#takePersistableUriPermission(Uri, int)
* @see ContentResolver#releasePersistableUriPermission(Uri, int)
* @see ContentResolver#getPersistedUriPermissions()
* @see ContentResolver#getOutgoingPersistedUriPermissions()
*/
区别于 FLAG_GRANT_READ_URI_PERMISSION 跟 FLAG_GRANT_WRITE_URI_PERMISSION， URI权限会持久存在即使重启，直到明确的用 revokeUriPermission(Uri, int) 撤销。 这个flag只提供可能持久授权。但是接收的应用必须调用ContentResolver的takePersistableUriPermission(Uri, int)方法实现 。
8.FLAG_GRANT_PREFIX_URI_PERMISSION
When combined with FLAG_GRANT_READ_URI_PERMISSION and/or FLAG_GRANT_WRITE_URI_PERMISSION, the URI permission grant applies to any URI that is a prefix match against the original granted URI. (Without this flag, the URI must match exactly for access to be granted.) Another URI is considered a prefix match only when scheme, authority, and all path segments defined by the prefix are an exact match. Uri 权限授予任何原始授权URI前缀匹配的URI。
9.FLAG_ACTIVITY_NO_HISTORY
/**
* If set, the new activity is not kept in the history stack. As soon as
* the user navigates away from it, the activity is finished. This may also
* be set with the {@link android.R.styleable#AndroidManifestActivity_noHistory
* noHistory} attribute.
*
* <p>If set, {@link android.app.Activity#onActivityResult onActivityResult()}
* is never invoked when the current activity starts a new activity which
* sets a result and finishes.
* 如果设置，新的activity将不会保存在历史栈中。一旦
* 用户离开这个activity，它就会被finish掉。
* 也可以在manifest.xml中设置activity android:hoHistory属性设置。
*如果设置， OnActivityResult()方法将不会再被调用 。
*
*/
- FLAG_ACTIVITY_SINGLE_TOP
/**
* If set, the activity will not be launched if it is already running
* at the top of the history stack.
* 如果设置了，如过Activity在栈顶将不会启动。
*/
11.FLAG_ACTIVITY_NEW_TASK
/**
* If set, this activity will become the start of a new task on this
* history stack. A task (from the activity that started it to the
* next task activity) defines an atomic group of activities that the
* user can move to. Tasks can be moved to the foreground and background;
* all of the activities inside of a particular task always remain in
* the same order. See
* <a href="{@docRoot}guide/topics/fundamentals/tasks-and-back-stack.html">Tasks and Back
* Stack</a> for more information about tasks.
*
* <p>This flag is generally used by activities that want
* to present a "launcher" style behavior: they give the user a list of
* separate things that can be done, which otherwise run completely
* independently of the activity launching them.
*
* <p>When using this flag, if a task is already running for the activity
* you are now starting, then a new activity will not be started; instead,
* the current task will simply be brought to the front of the screen with
* the state it was last in. See {@link #FLAG_ACTIVITY_MULTIPLE_TASK} for a flag
* to disable this behavior.
*
* <p>This flag can not be used when the caller is requesting a result from
* the activity being launched.
* 如果设置了，这个Activity将会成为新任务历史栈的开始
* 如果已经有一个task运行着邀请东的activity，将不会启动新的activity；当前任务栈最后状态
* 将会被展示在屏幕上 查看 FLAG_ACTIVITY_MULTIPLE_TASK ，关闭这一特性。
*/
12.FLAG_ACTIVITY_MULTIPLE_TASK
/**
* This flag is used to create a new task and launch an activity into it.
* This flag is always paired with either {@link #FLAG_ACTIVITY_NEW_DOCUMENT}
* or {@link #FLAG_ACTIVITY_NEW_TASK}. In both cases these flags alone would
* search through existing tasks for ones matching this Intent. Only if no such
* task is found would a new task be created. When paired with
* FLAG_ACTIVITY_MULTIPLE_TASK both of these behaviors are modified to skip
* the search for a matching task and unconditionally start a new task.
* 用来创建新的任务栈，启动activity。
* 总是跟 FLAG_ACTIVITY_NEW_DOCUMENT或FLAG_ACTIVITY_NEW_TASK一起用。
* 如果单独使用这两个，将从存在的任务栈中找寻匹配这个intent的。如果找不到，
* 将会重新创建task。当匹配的时候，都是为了更改然后跳过找到匹配task的步骤，然后无条件的启动新的
* task
* <strong>When used with {@link #FLAG_ACTIVITY_NEW_TASK} do not use this
* flag unless you are implementing your own
* top-level application launcher.</strong>
* 不要轻易跟FLAG_ACTIVITY_NEW_TASK结合使用，除非你在实现自己的top-level application
* launcher
* Used in conjunction with
* {@link #FLAG_ACTIVITY_NEW_TASK} to disable the
* behavior of bringing an existing task to the foreground. When set,
* a new task is <em>always</em> started to host the Activity for the
* Intent, regardless of whether there is already an existing task running
* the same thing.
* <p><strong>Because the default system does not include graphical task management,
* you should not use this flag unless you provide some way for a user to
* return back to the tasks you have launched.</strong>
* See {@link #FLAG_ACTIVITY_NEW_DOCUMENT} for details of this flag's use for
* creating new document tasks.
* <p>This flag is ignored if one of {@link #FLAG_ACTIVITY_NEW_TASK} or
* {@link #FLAG_ACTIVITY_NEW_DOCUMENT} is not also set.
* 只设置这个flag而不与其他匹配将被忽略掉。
*/
13.FLAG_ACTIVITY_CLEAR_TOP
/**
* If set, and the activity being launched is already running in the
* current task, then instead of launching a new instance of that activity,
* all of the other activities on top of it will be closed and this Intent
* will be delivered to the (now on top) old activity as a new Intent.
* 当设置此标致，并且acitivity已经启动，那么不是启动一个activity新势力，所有其他顶部的activity
* 都会关闭，这个intent将被交付到（现在顶部）老的activity 做为新的intent。
* <p>For example, consider a task consisting of the activities: A, B, C, D.
* If D calls startActivity() with an Intent that resolves to the component
* of activity B, then C and D will be finished and B receive the given
* Intent, resulting in the stack now being: A, B.
* 如果一个task由A,B,C,D组成，如果D调用startActivity（），跳到B, 然后C,D被finish掉，B
* 接收新的intent ，结果栈中：A,B.
* <p>The currently running instance of activity B in the above example will
* either receive the new intent you are starting here in its
* onNewIntent() method, or be itself finished and restarted with the
* new intent. If it has declared its launch mode to be "multiple" (the
* default) and you have not set {@link #FLAG_ACTIVITY_SINGLE_TOP} in
* the same intent, then it will be finished and re-created; for all other
* launch modes or if {@link #FLAG_ACTIVITY_SINGLE_TOP} is set then this
* Intent will be delivered to the current instance's onNewIntent().
* 现在运行的B的实例或者在onNewIntent方法中接收你start的新intent，或者自己finish掉然后重启
* 一个新的intent。如果声明启动了启动模式是“multiple”(默认)，并且你没有在这个intent中设置
* FLAG_ACTIVITY_SINGLE_TOP，就会finish掉然后重新创建。
* 其他的启动模式。或者FLAG_ACTIVITY_SINGLE_TOP被设置了，intent将会传送到当前实例的
* onNewIntent方法中。
*
* <p>This launch mode can also be used to good effect in conjunction with
* {@link #FLAG_ACTIVITY_NEW_TASK}: if used to start the root activity
* of a task, it will bring any currently running instance of that task
* to the foreground, and then clear it to its root state. This is
* especially useful, for example, when launching an activity from the
* notification manager.
* 这个启动模式也可以跟FLAG_ACTIVITY_NEW_TASK结合使用：如果用来start 根activity，它将会
* 此task任意当前正在执行的实例bring to foreground，然后清除到跟状态。这非常有用，比如，
* 当从notification manager启动一个activity。
*/
14.FLAG_ACTIVITY_FORWARD_RESULT
/**
* If set and this intent is being used to launch a new activity from an
* existing one, then the reply target of the existing activity will be
* transfered to the new activity. This way the new activity can call
* {@link android.app.Activity#setResult} and have that result sent back to
* the reply target of the original activity.
* 如果设置，并且这个Intent用于从一个存在的Activity启动一个新的Activity，那么，这个作为答复目标
* 的Activity将会传到这个新的Activity中。这种方式下，新的Activity可以调用setResult(int)，
* 并且这个结果值将发送给那个作为答复目标的Activity。
*/
15.FLAG_ACTIVITY_PREVIOUS_IS_TOP
/**
* If set and this intent is being used to launch a new activity from an
* existing one, the current activity will not be counted as the top
* activity for deciding whether the new intent should be delivered to
* the top instead of starting a new one. The previous activity will
* be used as the top, with the assumption being that the current activity
* will finish itself immediately.
* 如果给Intent对象设置了这个标记，并且这个Intent对象被用于从一个既存的Activity中启动一个新的
* Activity，这个Activity不被看作决定是否传送新的intent到top而不是start新的，
* 通常认为使用这个flag启动的Activity会被自己立即终止。
*/
16.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS
/**
* If set, the new activity is not kept in the list of recently launched
* activities.
* 如果设置，新的Activity不会在最近启动的Activity的列表中保存。
*/
17.FLAG_ACTIVITY_BROUGHT_TO_FRONT
/**
* This flag is not normally set by application code, but set for you by
* the system as described in the
* {@link android.R.styleable#AndroidManifestActivity_launchMode
* launchMode} documentation for the singleTask mode.
* 通常不是通过应用程序代码设置，而是通过系统如launchMode singleTask模式。
*/
18.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
/**
* If set, and this activity is either being started in a new task or
* bringing to the top an existing task, then it will be launched as
* the front door of the task. This will result in the application of
* any affinities needed to have that task in the proper state (either
* moving activities to or from it), or simply resetting that task to
* its initial state if needed.
* FLAG_ACTIVITY_RESET_TASK_IF_NEEDED:如果设置该属性，并且
* 这个activity在一个新的task中正在被启动或者被带到一个已经存在
* 的task的顶部，这时这个activity将会被作为这个task的首个页面加
* 载。这将会导致拥有这个应用的affinities的task处于一个合适的状
* 态(移动activity到这个task或者activity从中移出)，或者简单的
* 重置这个task到它的初始状态
*/
19.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY
/**
* This flag is not normally set by application code, but set for you by
* the system if this activity is being launched from history
* (longpress home key).
* 这个标记通常不由应用程序代码来设置，如果是从历史中启动这个Activity，系统就会设置这个标记。
* (长按home键)
*/
20.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET
/**
* @deprecated As of API 21 this performs identically to
* {@link #FLAG_ACTIVITY_NEW_DOCUMENT} which should be used instead of this.
* api21过期，被FLAG_ACTIVITY_NEW_DOCUMENT代替。
*/
21.FLAG_ACTIVITY_NEW_DOCUMENT
/**
* This flag is used to open a document into a new task rooted at the activity launched
* by this Intent. Through the use of this flag, or its equivalent attribute,
* {@link android.R.attr#documentLaunchMode} multiple instances of the same activity
* containing different documents will appear in the recent tasks list.
*
* <p>The use of the activity attribute form of this,
* {@link android.R.attr#documentLaunchMode}, is
* preferred over the Intent flag described here. The attribute form allows the
* Activity to specify multiple document behavior for all launchers of the Activity
* whereas using this flag requires each Intent that launches the Activity to specify it.
*
* <p>Note that the default semantics of this flag w.r.t. whether the recents entry for
* it is kept after the activity is finished is different than the use of
* {@link #FLAG_ACTIVITY_NEW_TASK} and {@link android.R.attr#documentLaunchMode} -- if
* this flag is being used to create a new recents entry, then by default that entry
* will be removed once the activity is finished. You can modify this behavior with
* {@link #FLAG_ACTIVITY_RETAIN_IN_RECENTS}.
*
* <p>FLAG_ACTIVITY_NEW_DOCUMENT may be used in conjunction with {@link
* #FLAG_ACTIVITY_MULTIPLE_TASK}. When used alone it is the
* equivalent of the Activity manifest specifying {@link
* android.R.attr#documentLaunchMode}="intoExisting". When used with
* FLAG_ACTIVITY_MULTIPLE_TASK it is the equivalent of the Activity manifest specifying
* {@link android.R.attr#documentLaunchMode}="always".
*
* Refer to {@link android.R.attr#documentLaunchMode} for more information.
*
* @see android.R.attr#documentLaunchMode
* @see #FLAG_ACTIVITY_MULTIPLE_TASK
* 可以跟FLAG_ACTIVITY_MULTIPLE_TASK结合使用，当只用自己的时候相当于Manifast中
* android.R.attr.documentLaunchMode="intoExisting"，当跟FLAG_ACTIVITY_MULTIPLE_TASK
* 结合使用相当于 Manifast中android.R.attr.documentLaunchMode="always".
*/
22.FLAG_ACTIVITY_NO_USER_ACTION
/**
* If set, this flag will prevent the normal {@link android.app.Activity#onUserLeaveHint}
* callback from occurring on the current frontmost activity before it is
* paused as the newly-started activity is brought to the front.
*
* <p>Typically, an activity can rely on that callback to indicate that an
* explicit user action has caused their activity to be moved out of the
* foreground. The callback marks an appropriate point in the activity's
* lifecycle for it to dismiss any notifications that it intends to display
* "until the user has seen them," such as a blinking LED.
*
* <p>If an activity is ever started via any non-user-driven events such as
* phone-call receipt or an alarm handler, this flag should be passed to {@link
* Context#startActivity Context.startActivity}, ensuring that the pausing
* activity does not think the user has acknowledged its notification.
* onUserLeaveHint()作为activity周期的一部分，它在activity因为用户要跳转到别的activity而要退
* 到background时使用。比如,在用户按下Home键，它将被调用。比如有电话进来（不属于用户的选择），它
* 就不会被调用。
* 如果设置，作为新启动的Activity进入前台时，这个标志将在Activity暂停之前阻止从最前方的Activity
* 回调的onUserLeaveHint()。典型的，一个Activity可以依赖这个回调指明显式的用户动作引起的
* Activity移出后台。这个回调在Activity的生命周期中标记一个合适的点，并关闭一些Notification。
* 如果一个Activity通过非用户驱动的事件，如来电或闹钟，启动的，这个标志也应该传递给
* Context.startActivity，保证暂停的Activity不认为用户已经知晓其Notification。
*/
23.FLAG_ACTIVITY_REORDER_TO_FRONT
/**
* If set in an Intent passed to {@link Context#startActivity Context.startActivity()},
* this flag will cause the launched activity to be brought to the front of its
* task's history stack if it is already running.
* 如果在intent里设置交给 startActivity（）,这个flag会把已经运行过的acivity带到task历史
* 栈的顶端。
*
* <p>For example, consider a task consisting of four activities: A, B, C, D.
* If D calls startActivity() with an Intent that resolves to the component
* of activity B, then B will be brought to the front of the history stack,
* with this resulting order: A, C, D, B.
* 例如，一个task由A,B,C,D四个activity组成，如果D哦赢携带这个flag的intent调用
* startActivity()打开B，那么B就会被带到历史栈的前部，结果是:A,C,D,B.
*
* This flag will be ignored if {@link #FLAG_ACTIVITY_CLEAR_TOP} is also
* specified.
* 如果LAG_ACTIVITY_CLEAR_TOP 被设置，那么FLAG_ACTIVITY_REORDER_TO_FRONT
* 将被忽略。
*/
24.FLAG_ACTIVITY_NO_ANIMATION
/**
* If set in an Intent passed to {@link Context#startActivity Context.startActivity()},
* this flag will prevent the system from applying an activity transition
* animation to go to the next activity state. This doesn't mean an
* animation will never run -- if another activity change happens that doesn't
* specify this flag before the activity started here is displayed, then
* that transition will be used. This flag can be put to good use
* when you are going to do a series of activity operations but the
* animation seen by the user shouldn't be driven by the first activity
* change but rather a later one.
* 如果设置，将阻止系统get next activity的过渡动画。并不意味着一直不会有动画，--如果另一个
* activity 的变化发生没有在start activity 显示之前指定，会有过渡动画。
*/
25.FLAG_ACTIVITY_CLEAR_TASK
/**
* If set in an Intent passed to {@link Context#startActivity Context.startActivity()},
* this flag will cause any existing task that would be associated with the
* activity to be cleared before the activity is started. That is, the activity
* becomes the new root of an otherwise empty task, and any old activities
* are finished. This can only be used in conjunction with {@link #FLAG_ACTIVITY_NEW_TASK}.
* 如果在通过Context.startActivity()启动activity时为Intent设置了此标识，这个标识将导致：
* 在此activity启动之前，任何与此activity相关联的task都会被清除。也就是说，
* 此activity将变成一个空栈中新的最底端的activity，所有的旧activity都会被finish掉，
* 这个标识仅仅和FLAG_ACTIVITY_NEW_TASK联合起来才能使用。
*/
26.FLAG_ACTIVITY_TASK_ON_HOME
/**
* If set in an Intent passed to {@link Context#startActivity Context.startActivity()},
* this flag will cause a newly launching task to be placed on top of the current
* home activity task (if there is one). That is, pressing back from the task
* will always return the user to home even if that was not the last activity they
* saw. This can only be used in conjunction with {@link #FLAG_ACTIVITY_NEW_TASK}.
* 把当前新启动的任务置于Home任务之上，也就是按back键从这个任务返回的时候会回到home，
* 即使这个不是他们最后看见的activity，注意这个标记必须和FLAG_ACTIVITY_NEW_TASK一起使用
*/
27.FLAG_ACTIVITY_RETAIN_IN_RECENTS
/**
* By default a document created by {@link #FLAG_ACTIVITY_NEW_DOCUMENT} will
* have its entry in recent tasks removed when the user closes it (with back
* or however else it may finish()). If you would like to instead allow the
* document to be kept in recents so that it can be re-launched, you can use
* this flag. When set and the task's activity is finished, the recents
* entry will remain in the interface for the user to re-launch it, like a
* recents entry for a top-level application.
* 默认情况FLAG_ACTIVITY_NEW_DOCUMENT创建的document当用户关闭时之前tasks的entry会被remove
* 掉，如果想保持在历史中一遍重新launch，就要用到这个flag.当使task的activity finish掉以后，
* 历史entry将保持在界面以便用户重新打开类似顶级应用程序的历史。
* <p>
* The receiving activity can override this request with
* {@link android.R.attr#autoRemoveFromRecents} or by explcitly calling
* {@link android.app.Activity#finishAndRemoveTask()
* Activity.finishAndRemoveTask()}.
*
*/
28.FLAG_RECEIVER_REGISTERED_ONLY
/**
* If set, when sending a broadcast only registered receivers will be
* called -- no BroadcastReceiver components will be launched.
* 设置这个flag，发送广播只有动态注册才能调用，组件(xml 中定义action)不会被被launch.
*/
29.FLAG_RECEIVER_REPLACE_PENDING
/**
* If set, when sending a broadcast the new broadcast will replace
* any existing pending broadcast that matches it. Matching is defined
* by {@link Intent#filterEquals(Intent) Intent.filterEquals} returning
* true for the intents of the two broadcasts. When a match is found,
* the new broadcast (and receivers associated with it) will replace the
* existing one in the pending broadcast list, remaining at the same
* position in the list.
* 这个flag 将会将之前的Intent 替代掉。加了这个flag，在发送一系列的这样的Intent 之后，
* 中间有些Intent 有可能在你还没有来得及处理的时候，就被替代掉了。
*
* <p>This flag is most typically used with sticky broadcasts, which
* only care about delivering the most recent values of the broadcast
* to their receivers.
*/
30.FLAG_RECEIVER_FOREGROUND
/**
* If set, when sending a broadcast the recipient is allowed to run at
* foreground priority, with a shorter timeout interval. During normal
* broadcasts the receivers are not automatically hoisted out of the
* background priority class.
* 当发送广播时，允许其接受者 在前台运行的拥有更高的优先级，更短的超时间隔。
*/
31.FLAG_RECEIVER_NO_ABORT
/**
* If this is an ordered broadcast, don't allow receivers to abort the broadcast.
* They can still propagate results through to later receivers, but they can not
* prevent later receivers from seeing the broadcast.
* 如果是有序广播，不要允许接收者中断广播播。
*
*/
32.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT
/**
* If set, when sending a broadcast <i>before boot has completed</i> only
* registered receivers will be called -- no BroadcastReceiver components
* will be launched. Sticky intent state will be recorded properly even
* if no receivers wind up being called. If {@link #FLAG_RECEIVER_REGISTERED_ONLY}
* is specified in the broadcast intent, this flag is unnecessary.
* 在boot完成前发送广播，只有注册了的接收者才会被调用,xml中的无法launch.
*
* <p>This flag is only for use by system sevices as a convenience to
* avoid having to implement a more complex mechanism around detection
* of boot completion.
*
* @hide
*/
33.FLAG_RECEIVER_BOOT_UPGRADE
/**
* Set when this broadcast is for a boot upgrade, a special mode that
* allows the broadcast to be sent before the system is ready and launches
* the app process with no providers running in it.
* 系统更新广播，一个允许播放在系统准备好和launch app 进程之前发送的模式
* @hide
*/