timg.jpeg
android启动模式的实现一般分两种，一种在代码里面startActivity的时候添加flag实现，一种是在AndroidManifest中添加launchMode实现。 如果两个地方都加了，就会是叠加的效果。
一.flag例子：桌面点击图标是什么参数？
默认情况点击图标时：
ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.wenfengtou.firstmacapp/.MainActivity bnds=[539,717][790,1001]} from uid 10028 and from pid 2458
可以看到flag时0x10200000，对应的flag就是
FLAG_ACTIVITY_NEW_TASK
FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
FLAG_ACTIVITY_NEW_TASK标志，如果要启动的Activity在后台，就会把Activity所在的Task推到前台显示，要注意不一定显示要启动的Activity，而是显示Task上处于TOP位置的Activity。例如点击桌面图标，启动A，在A中启动B，点击home键返回桌面，再次点击桌面图标，会显示B，因为B处于TOP的位置。
使用adb模拟桌面点击：
am start -n com.example.wenfengtou.firstmacapp/.MainActivity -f 0x10200000 -c android.intent.category.LAUNCHER -a android.intent.action.MAIN
注意一定注意保证action和catroy一样，否则会启动一下新的A，栈的情况就会是A－B－A
二.Launchmode例子：如何实现点击桌面图标会回到首页？
Launchmode有四种
public static final int LAUNCH_MULTIPLE = 0;
/**
* Constant corresponding to singleTop in
* the {@link android.R.attr#launchMode} attribute.
*/
public static final int LAUNCH_SINGLE_TOP = 1;
/**
* Constant corresponding to singleTask in
* the {@link android.R.attr#launchMode} attribute.
*/
public static final int LAUNCH_SINGLE_TASK = 2;
/**
* Constant corresponding to singleInstance in
* the {@link android.R.attr#launchMode} attribute.
*/
public static final int LAUNCH_SINGLE_INSTANCE = 3;
可以通过dumpsys activity a 来查看启动的Activity的launchmode。
Task id #28869
mFullscreen=true
mBounds=null
mMinWidth=-1
mMinHeight=-1
mLastNonFullscreenBounds=null
* TaskRecord{51e69b4 #28869 A=com.example.wenfengtou.firstmacapp U=0 StackId=1 sz=1}
userId=0 effectiveUid=u0a218 mCallingUid=u0a218 mUserSetupComplete=true mCallingPackage=com.example.wenfengtou.firstmacapp
affinity=com.example.wenfengtou.firstmacapp
intent={flg=0x10104000 cmp=com.example.wenfengtou.firstmacapp/.Sencond}
realActivity=com.example.wenfengtou.firstmacapp/.Sencond
autoRemoveRecents=false isPersistable=true numFullscreen=1 taskType=0 mTaskToReturnTo=1
rootWasReset=false mNeverRelinquishIdentity=true mReuseTask=false mLockTaskAuth=LOCK_TASK_AUTH_PINNABLE
Activities=[ActivityRecord{8fcae2a u0 com.example.wenfengtou.firstmacapp/.Sencond t28869}]
askedCompatMode=false inRecents=false isAvailable=true
lastThumbnail=null lastThumbnailFile=/data/system_ce/0/recent_images/28869_task_thumbnail.png
stackId=1
hasBeenVisible=true mResizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION mSupportsPictureInPicture=false isResizeable=true firstActiveTime=1532758042288 lastActiveTime=1532758200753 (inactive for 1310s)
* Hist #0: ActivityRecord{8fcae2a u0 com.example.wenfengtou.firstmacapp/.Sencond t28869}
packageName=com.example.wenfengtou.firstmacapp processName=com.example.wenfengtou.firstmacapp
launchedFromUid=10218 launchedFromPackage=com.example.wenfengtou.firstmacapp userId=0
app=ProcessRecord{cfd9c93 27860:com.example.wenfengtou.firstmacapp/u0a218}
Intent { flg=0x10104000 cmp=com.example.wenfengtou.firstmacapp/.Sencond }
frontOfTask=true task=TaskRecord{51e69b4 #28869 A=com.example.wenfengtou.firstmacapp U=0 StackId=1 sz=1}
taskAffinity=com.example.wenfengtou.firstmacapp
realActivity=com.example.wenfengtou.firstmacapp/.Sencond
baseDir=/data/app/com.example.wenfengtou.firstmacapp-eLkTGBVSXt9xqMyC0HtQKQ==/base.apk
dataDir=/data/user/0/com.example.wenfengtou.firstmacapp
stateNotNeeded=false componentSpecified=true mActivityType=0
compat={480dpi} labelRes=0x7f060021 icon=0x7f030000 theme=0x0
mLastReportedConfigurations:
mGlobalConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw360dp w360dp h685dp 480dpi nrml long port finger -keyb/v/h -nav/h appBounds=Rect(0, 0 - 1080, 2136) s.28mThemeChanged = 0mThemeChangedFlags = 0mFlipFont = 0}
mOverrideConfig={1.0 ?mcc?mnc [zh_CN] ldltr sw360dp w360dp h685dp 480dpi nrml long port finger -keyb/v/h -nav/h appBounds=Rect(0, 0 - 1080, 2136) s.28mThemeChanged = 0mThemeChangedFlags = 0mFlipFont = 0}
CurrentConfiguration={1.0 ?mcc?mnc [zh_CN] ldltr sw360dp w360dp h685dp 480dpi nrml long port finger -keyb/v/h -nav/h appBounds=Rect(0, 0 - 1080, 2136) s.28mThemeChanged = 0mThemeChangedFlags = 0mFlipFont = 0}
taskDescription: iconFilename=null label="null" primaryColor=ff212121
backgroundColor=fffafafa
statusBarColor=ff000000
navigationBarColor=0
launchFailed=false launchCount=0 lastLaunchTime=-22m24s866ms
haveState=true icicle=Bundle[mParcelledData.dataSize=860]
state=STOPPED stopped=true delayedResume=false finishing=false
keysPaused=false inHistory=true visible=false sleeping=false idle=true mStartingWindowState=STARTING_WINDOW_REMOVED
fullscreen=true noDisplay=false immersive=false launchMode=0
四种launchmode简介：
standard：普通模式，启动activity都会新建。
singletop：如果要启动的Activity在top了，就不会新建Activity。如果不在，就新建一个。
singletask：如果要启动的activity在top了，就不会新建Activity（这种情况跟singletop一样）。如果不在top，而是在中间，就会清空他头上的所有activity。如果没创建过该activity，就会新建一个在top。
singleinstance：会在一个单独的task里面。
所以，如何如何实现点击桌面图标会回到首页？
例如首页时A，然后A启动了B，B启动了C。然后点击home键，如何实现点击桌面图片回到A呢？
答案就是设置A的Launchmode为singletask就可以了。因为他会清空他头上的B和C。
平安产险：
一个应用可以有多个task吗？
可以。
方式有两种：
1.启动一个launchmode为singleinstance的activity，就用启动一个新的task。
2.启动一个亲和度不一样的activity，并且是这个activity的launchmode是singletask（或者intent的flag设置成FLAG_ACTIVITY_NEW_TASK）
com.example.wenfengtou.firstmacapp/.Sencond就是设置了singletask并且亲和度为com.wenfengtou的Activity。可以看到跟
com.example.wenfengtou.firstmacapp/.MainActivity在不同的Task里面。一个在Task ＃29，一个在Task ＃28。
Task id #29
mFullscreen=true
mBounds=null
mMinWidth=-1
mMinHeight=-1
mLastNonFullscreenBounds=null
* TaskRecord{1e02dad #29 A=com.wenfengtou U=0 StackId=1 sz=1}
userId=0 effectiveUid=u0a84 mCallingUid=u0a84 mUserSetupComplete=true mCallingPackage=com.example.wenfengtou.firstmacapp
affinity=com.wenfengtou
intent={flg=0x10000000 cmp=com.example.wenfengtou.firstmacapp/.Sencond}
realActivity=com.example.wenfengtou.firstmacapp/.Sencond
autoRemoveRecents=false isPersistable=true numFullscreen=1 taskType=0 mTaskToReturnTo=0
rootWasReset=false mNeverRelinquishIdentity=true mReuseTask=false mLockTaskAuth=LOCK_TASK_AUTH_PINNABLE
Activities=[ActivityRecord{8e058d0 u0 com.example.wenfengtou.firstmacapp/.Sencond t29}]
askedCompatMode=false inRecents=true isAvailable=true
lastThumbnail=null lastThumbnailFile=/data/system_ce/0/recent_images/29_task_thumbnail.png
stackId=1
hasBeenVisible=true mResizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION mSupportsPictureInPicture=false isResizeable=true firstActiveTime=1553332838382 lastActiveTime=1553332838382 (inactive for 12s)
* Hist #0: ActivityRecord{8e058d0 u0 com.example.wenfengtou.firstmacapp/.Sencond t29}
packageName=com.example.wenfengtou.firstmacapp processName=com.example.wenfengtou.firstmacapp
launchedFromUid=10084 launchedFromPackage=com.example.wenfengtou.firstmacapp userId=0
app=ProcessRecord{b2c58e2 20808:com.example.wenfengtou.firstmacapp/u0a84}
Intent { flg=0x10000000 cmp=com.example.wenfengtou.firstmacapp/.Sencond }
frontOfTask=true task=TaskRecord{1e02dad #29 A=com.wenfengtou U=0 StackId=1 sz=1}
taskAffinity=com.wenfengtou
realActivity=com.example.wenfengtou.firstmacapp/.Sencond
baseDir=/data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/base.apk
dataDir=/data/user/0/com.example.wenfengtou.firstmacapp
splitDir=[/data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_dependencies_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_0_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_1_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_2_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_3_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_4_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_5_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_6_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_7_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_8_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_9_apk.apk]
stateNotNeeded=false componentSpecified=true mActivityType=0
compat={420dpi} labelRes=0x7f060021 icon=0x7f030000 theme=0x0
mLastReportedConfigurations:
mGlobalConfig={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
mOverrideConfig={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
CurrentConfiguration={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
taskDescription: iconFilename=null label="null" primaryColor=ff212121
backgroundColor=fffafafa
statusBarColor=ff000000
navigationBarColor=ff000000
launchFailed=false launchCount=1 lastLaunchTime=-12s339ms
haveState=false icicle=null
state=RESUMED stopped=false delayedResume=false finishing=false
keysPaused=false inHistory=true visible=true sleeping=false idle=true mStartingWindowState=STARTING_WINDOW_SHOWN
fullscreen=true noDisplay=false immersive=false launchMode=2
frozenBeforeDestroy=false forceNewConfig=false
mActivityType=APPLICATION_ACTIVITY_TYPE
waitingVisible=false nowVisible=true lastVisibleTime=-11s158ms
resizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION
mLastReportedMultiWindowMode=false mLastReportedPictureInPictureMode=false
Task id #28
mFullscreen=true
mBounds=null
mMinWidth=-1
mMinHeight=-1
mLastNonFullscreenBounds=null
* TaskRecord{5c2e473 #28 A=com.example.wenfengtou.firstmacapp U=0 StackId=1 sz=1}
userId=0 effectiveUid=u0a84 mCallingUid=2000 mUserSetupComplete=true mCallingPackage=null
affinity=com.example.wenfengtou.firstmacapp
intent={act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.wenfengtou.firstmacapp/.MainActivity}
realActivity=com.example.wenfengtou.firstmacapp/.MainActivity
autoRemoveRecents=false isPersistable=true numFullscreen=1 taskType=0 mTaskToReturnTo=1
rootWasReset=false mNeverRelinquishIdentity=true mReuseTask=false mLockTaskAuth=LOCK_TASK_AUTH_PINNABLE
Activities=[ActivityRecord{c281c10 u0 com.example.wenfengtou.firstmacapp/.MainActivity t28}]
askedCompatMode=false inRecents=true isAvailable=true
lastThumbnail=null lastThumbnailFile=/data/system_ce/0/recent_images/28_task_thumbnail.png
stackId=1
hasBeenVisible=true mResizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION mSupportsPictureInPicture=false isResizeable=true firstActiveTime=1553332838281 lastActiveTime=1553332838281 (inactive for 12s)
* Hist #0: ActivityRecord{c281c10 u0 com.example.wenfengtou.firstmacapp/.MainActivity t28}
packageName=com.example.wenfengtou.firstmacapp processName=com.example.wenfengtou.firstmacapp
launchedFromUid=2000 launchedFromPackage=null userId=0
app=ProcessRecord{b2c58e2 20808:com.example.wenfengtou.firstmacapp/u0a84}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.wenfengtou.firstmacapp/.MainActivity }
frontOfTask=true task=TaskRecord{5c2e473 #28 A=com.example.wenfengtou.firstmacapp U=0 StackId=1 sz=1}
taskAffinity=com.example.wenfengtou.firstmacapp
realActivity=com.example.wenfengtou.firstmacapp/.MainActivity
baseDir=/data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/base.apk
dataDir=/data/user/0/com.example.wenfengtou.firstmacapp
splitDir=[/data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_dependencies_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_0_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_1_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_2_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_3_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_4_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_5_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_6_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_7_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_8_apk.apk, /data/app/com.example.wenfengtou.firstmacapp-MLcE0o9GmJ6AneQdbCfeQw==/split_lib_slice_9_apk.apk]
stateNotNeeded=false componentSpecified=true mActivityType=0
compat={420dpi} labelRes=0x7f060021 icon=0x7f030000 theme=0x0
mLastReportedConfigurations:
mGlobalConfig={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
mOverrideConfig={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
CurrentConfiguration={1.0 310mcc260mnc [en_US] ldltr sw411dp w411dp h659dp 420dpi nrml port finger qwerty/v/v -nav/h appBounds=Rect(0, 0 - 1080, 1794) s.6}
taskDescription: iconFilename=null label="null" primaryColor=ff212121
backgroundColor=fffafafa
statusBarColor=ff000000
navigationBarColor=ff000000
launchFailed=false launchCount=0 lastLaunchTime=-19s42ms
haveState=true icicle=Bundle[mParcelledData.dataSize=936]
state=STOPPED stopped=true delayedResume=false finishing=false
keysPaused=false inHistory=true visible=false sleeping=false idle=true mStartingWindowState=STARTING_WINDOW_REMOVED
fullscreen=true noDisplay=false immersive=false launchMode=1
frozenBeforeDestroy=false forceNewConfig=false
mActivityType=APPLICATION_ACTIVITY_TYPE
waitingVisible=false nowVisible=false lastVisibleTime=-16s673ms
resizeMode=RESIZE_MODE_RESIZEABLE_VIA_SDK_VERSION
mLastReportedMultiWindowMode=false mLastReportedPictureInPictureMode=false
AndroidManifest是如下设置
SingleInstance的task中只能有一个activity 吗？
对的。
一个ActivityA的taskAffinity为com.wenfengtou，Activity所在的Task的taskAffinity也为com.wenfengtou，那么他启动一个另一个taskAffinity的ActivityB，这个Activity会在哪个Task里面？
如果ActiviyB的启动模式是standard，会在ActivityA的TASK里面。
如果ActivityB的启动模式是SingleTask，就不回在ActivitA的TASK里面。