正常情況下，每一個Android應用啟動後都會對應一個程序，當前越來越多應用會有多個程序，為了推送，為了記憶體，或者為了保活。如何檢視應用程序呢。

1.DOS下面cmd，然後開啟adb shell，直接ps命令，顯示當前手機所有程序，如圖所示：

2.利用(ps|grep 條目名稱)命令，過濾自己需要的程序，比如列出條目裡含有tencent字元的程序（包名裡面含有該字元），則輸入ps|grep tencent，如圖所示則，QQ包含的程序下面幾個：

各列引數意義：

USER 程序當前使用者；

PID Process ID，程序ID；

PPID Process Parent ID，程序的父程序ID；

VSIZE Virtual Size，程序的虛擬記憶體大小；

RSS Resident Set Size，實際駐留”在記憶體中”的記憶體大小；

WCHAN 休眠程序在核心中的地址；

PC Program Counter；

NAME 程序名；

3.還有比較重要的兩個是程序的Importance等級以及adj值，關於這兩個定義大家可以不必深究，但是要有一定的理解，這兩個玩意是具體決定了系統在資源吃緊的情況下該殺掉哪些程序。通過cat /proc/程序id/oom_adj可以看到當前程序的adj指，比如輸入cat /proc/32366/oom_adj

cat檢視程序的adj值後我們會得到其返回結果“0”，說明當前程序正位於前臺，因為我的手機qq是開啟的。
同樣，我按home鍵，把qq退到後臺，這個時候，再輸入cat /proc/32366/oom_adj，則如下結果

而adj值則在ProcessList中定義：

final class ProcessList {
// OOM adjustments for processes in various states:

// Adjustment used in certain places where we don't know it yet.
// (Generally this is something that is going to be cached, but we
// don't know the exact value in the cached range to assign yet.)
static
 
 final int UNKNOWN_ADJ = 16;

// This is a process only hosting activities that are not visible,
// so it can be killed without any disruption.
static final int CACHED_APP_MAX_ADJ = 15;
static final int CACHED_APP_MIN_ADJ = 9;

// The B list of SERVICE_ADJ -- these are the old and decrepit
// services that aren't as shiny and interesting as the ones in the A list.
static final int SERVICE_B_ADJ = 8;

// This is the process of the previous application that the user was in.
// This process is kept above other things, because it is very common to
// switch back to the previous app.  This is important both for recent
// task switch (toggling between the two top recent apps) as well as normal
// UI flow such as clicking on a URI in the e-mail app to view in the browser,
// and then pressing back to return to e-mail.
static final int PREVIOUS_APP_ADJ = 7;

// This is a process holding the home application -- we want to try
// avoiding killing it, even if it would normally be in the background,
// because the user interacts with it so much.
static final int HOME_APP_ADJ = 6;

// This is a process holding an application service -- killing it will not
// have much of an impact as far as the user is concerned.
static final int SERVICE_ADJ = 5;

// This is a process with a heavy-weight application.  It is in the
// background, but we want to try to avoid killing it.  Value set in
// system/rootdir/init.rc on startup.
static final int HEAVY_WEIGHT_APP_ADJ = 4;

// This is a process currently hosting a backup operation.  Killing it
// is not entirely fatal but is generally a bad idea.
static final int BACKUP_APP_ADJ = 3;

// This is a process only hosting components that are perceptible to the
// user, and we really want to avoid killing them, but they are not
// immediately visible. An example is background music playback.
static final int PERCEPTIBLE_APP_ADJ = 2;

// This is a process only hosting activities that are visible to the
// user, so we'd prefer they don't disappear.
static final int VISIBLE_APP_ADJ = 1;

// This is the process running the current foreground app.  We'd really
// rather not kill it!
static final int FOREGROUND_APP_ADJ = 0;

// This is a process that the system or a persistent process has bound to,
// and indicated it is important.
static final int PERSISTENT_SERVICE_ADJ = -11;

// This is a system persistent process, such as telephony.  Definitely
// don't want to kill it, but doing so is not completely fatal.
static final int PERSISTENT_PROC_ADJ = -12;

// The system process runs at the default adjustment.
static final int SYSTEM_ADJ = -16;

// Special code for native processes that are not being managed by the system (so
// don't have an oom adj assigned by the system).
static final int NATIVE_ADJ = -17;
}

相較於Importance等級而言adj值可以賦予我們更多的參考價值，從上述adj值的定義中我們可以看到，值越小優先順序越高，比如native程序的adj值為－17，對於這個adj值的程序來說，系統根本不會動它一分一毫，實質上當程序的adj值去到2時系統就很少會因為其它原因而去殺死它，這些在研究程序保活中都非常重要。