下面列出了android.content.ComponentCallbacks2#TRIM_MEMORY_BACKGROUND 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。
@Override
public void onTrimMemory(int level) {
// Determine which lifecycle or system event was raised.
switch (level) {
case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:
case ComponentCallbacks2.TRIM_MEMORY_BACKGROUND:
case ComponentCallbacks2.TRIM_MEMORY_MODERATE:
case ComponentCallbacks2.TRIM_MEMORY_COMPLETE:
// Curently ignore these levels. They are handled somewhere else.
break;
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE:
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW:
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL:
// It looks like these come in all at the same time so just always suspend inactive Sessions.
Log.d(LOGTAG, "Memory pressure, suspending inactive sessions.");
SessionStore.get().suspendAllInactiveSessions();
break;
default:
Log.e(LOGTAG, "onTrimMemory unknown level: " + level);
break;
}
}
/**
* @inheritDoc
*/
@Override
public void trimMemory(int level) {
if(level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
emptyCache(); //dump the cache
}
else if (level >= ComponentCallbacks2.TRIM_MEMORY_MODERATE){
trimCache(0.5f); // trim to half the max size
}
else if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND){
trimCache(0.7f); // trim to one seventh max size
}
else if (level >= ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL){
trimCache(0.2f); // trim to one fifth max size
}
}
/**
* 获取修剪级别的名称
*/
@NonNull
public static String getTrimLevelName(int level) {
switch (level) {
case ComponentCallbacks2.TRIM_MEMORY_COMPLETE:
return "COMPLETE";
case ComponentCallbacks2.TRIM_MEMORY_MODERATE:
return "MODERATE";
case ComponentCallbacks2.TRIM_MEMORY_BACKGROUND:
return "BACKGROUND";
case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:
return "UI_HIDDEN";
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL:
return "RUNNING_CRITICAL";
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW:
return "RUNNING_LOW";
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE:
return "RUNNING_MODERATE";
default:
return "UNKNOWN";
}
}
public static void maybeNotifyMemoryPresure(int level) {
if (level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
nativeOnMemoryPressure(MemoryPressureLevel.CRITICAL);
} else if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND
|| level == ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL) {
// Don't notifiy on TRIM_MEMORY_UI_HIDDEN, since this class only
// dispatches actionable memory pressure signals to native.
nativeOnMemoryPressure(MemoryPressureLevel.MODERATE);
}
}
public static void maybeNotifyMemoryPresure(int level) {
if (level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
nativeOnMemoryPressure(MemoryPressureLevelList.MEMORY_PRESSURE_CRITICAL);
} else if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND ||
level == ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL) {
// Don't notifiy on TRIM_MEMORY_UI_HIDDEN, since this class only
// dispatches actionable memory pressure signals to native.
nativeOnMemoryPressure(MemoryPressureLevelList.MEMORY_PRESSURE_MODERATE);
}
}
public static void maybeNotifyMemoryPresure(int level) {
if (level >= ComponentCallbacks2.TRIM_MEMORY_COMPLETE) {
nativeOnMemoryPressure(MemoryPressureLevelList.MEMORY_PRESSURE_CRITICAL);
} else if (level >= ComponentCallbacks2.TRIM_MEMORY_BACKGROUND ||
level == ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL) {
// Don't notifiy on TRIM_MEMORY_UI_HIDDEN, since this class only
// dispatches actionable memory pressure signals to native.
nativeOnMemoryPressure(MemoryPressureLevelList.MEMORY_PRESSURE_MODERATE);
}
}
int runSendTrimMemory(PrintWriter pw) throws RemoteException {
int userId = UserHandle.USER_CURRENT;
String opt;
while ((opt = getNextOption()) != null) {
if (opt.equals("--user")) {
userId = UserHandle.parseUserArg(getNextArgRequired());
if (userId == UserHandle.USER_ALL) {
getErrPrintWriter().println("Error: Can't use user 'all'");
return -1;
}
} else {
getErrPrintWriter().println("Error: Unknown option: " + opt);
return -1;
}
}
String proc = getNextArgRequired();
String levelArg = getNextArgRequired();
int level;
switch (levelArg) {
case "HIDDEN":
level = ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN;
break;
case "RUNNING_MODERATE":
level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE;
break;
case "BACKGROUND":
level = ComponentCallbacks2.TRIM_MEMORY_BACKGROUND;
break;
case "RUNNING_LOW":
level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW;
break;
case "MODERATE":
level = ComponentCallbacks2.TRIM_MEMORY_MODERATE;
break;
case "RUNNING_CRITICAL":
level = ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL;
break;
case "COMPLETE":
level = ComponentCallbacks2.TRIM_MEMORY_COMPLETE;
break;
default:
try {
level = Integer.parseInt(levelArg);
} catch (NumberFormatException e) {
getErrPrintWriter().println("Error: Unknown level option: " + levelArg);
return -1;
}
}
if (!mInterface.setProcessMemoryTrimLevel(proc, userId, level)) {
getErrPrintWriter().println("Unknown error: failed to set trim level");
return -1;
}
return 0;
}
@Override
public void onTrimMemory(int level) {
super.onTrimMemory(level);
LogUtil.d(TAG, "\"" + TAG + "\": Application trim memory");
switch (level) {
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE:
LogUtil.d(TAG, "Trim memory: Running moderate");
break;
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW:
LogUtil.d(TAG, "Trim memory: Running low");
break;
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL:
LogUtil.d(TAG, "Trim memory: Running critical");
break;
case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:
LogUtil.d(TAG, "Trim memory: UI hidden");
break;
case ComponentCallbacks2.TRIM_MEMORY_BACKGROUND:
LogUtil.d(TAG, "Trim memory: Background");
break;
case ComponentCallbacks2.TRIM_MEMORY_MODERATE:
LogUtil.d(TAG, "Trim memory: Moderate");
break;
case ComponentCallbacks2.TRIM_MEMORY_COMPLETE:
LogUtil.d(TAG, "Trim memory: Complete");
if (sPackageName == null) {
sPackageName = getPackageName();
}
if (sFilesDirMemory == null) {
sFilesDirMemory = getFilesDir();
}
if (sFilesDirPathMemory == null) {
sFilesDirPathMemory = getFilesDir().getPath();
}
if (sCacheDirMemory == null) {
sCacheDirMemory = getCacheDir();
}
if (sCacheDirPathMemory == null) {
sCacheDirPathMemory = getCacheDir().getPath();
}
break;
}
}
/**
* Release memory when the UI becomes hidden or when system resources become low.
*
* @param level the memory-related event that was raised.
*/
public void onTrimMemory(int level) {
super.onTrimMemory(level);
// Determine which lifecycle or system event was raised.
switch (level) {
case ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN:
/*
Release any UI objects that currently hold memory.
"release your UI resources" is actually about things like caches.
You usually don't have to worry about managing views or UI components because the OS
already does that, and that's why there are all those callbacks for creating, starting,
pausing, stopping and destroying an activity.
The user interface has moved to the background.
*/
break;
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_MODERATE:
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_LOW:
case ComponentCallbacks2.TRIM_MEMORY_RUNNING_CRITICAL:
picassoCache.clear();
/*
Release any memory that your app doesn't need to run.
The device is running low on memory while the app is running.
The event raised indicates the severity of the memory-related event.
If the event is TRIM_MEMORY_RUNNING_CRITICAL, then the system will
begin killing background processes.
*/
break;
case ComponentCallbacks2.TRIM_MEMORY_BACKGROUND:
case ComponentCallbacks2.TRIM_MEMORY_MODERATE:
case ComponentCallbacks2.TRIM_MEMORY_COMPLETE:
picassoCache.clear();
/*
Release as much memory as the process can.
The app is on the LRU list and the system is running low on memory.
The event raised indicates where the app sits within the LRU list.
If the event is TRIM_MEMORY_COMPLETE, the process will be one of
the first to be terminated.
*/
break;
default:
/*
Release any non-critical data structures.
The app received an unrecognized memory level value
from the system. Treat this as a generic low-memory message.
*/
break;
}
}