本篇文章主要介紹 Android 9.0 Crash 機(jī)制部分知識(shí)點(diǎn)，通過(guò)閱讀本篇文章，您將收獲以下內(nèi)容:
一、Crash 概述
二、Crash處理流程
三、handleApplicationCrash處理分析
四、handleApplicationCrashInner 處理分析
五、APP Error info分析
六、makeAppCrashingLocked處理分析
七、startAppProblemLocked處理分析
八、stopFreezingAllLocked處理分析
Android 9.0 Crash 機(jī)制調(diào)用鏈
/frameworks/base/core/JAVA/com/android/internal/os/RuntimeInit.java /frameworks/base/core/java/android/app/ActivityManagerNative.java (含內(nèi)部類AMP) /frameworks/base/core/java/android/app/ApplicationErrorReport.java /frameworks/base/services/core/java/com/android/server/ - am/ActivityManagerService.java - am/ProcessRecord.java - am/ActivityRecord.java - am/ActivityStackSupervisor.java - am/ActivityStack.java - am/ActivityRecord.java - am/BroadcastQueue.java - wm/WindowManagerService.java /libcore/libart/src/main/java/java/lang/Thread.java
一、Crash 概述
App Crash (全稱Application Crash), 對(duì)于Crash可分為Native Crash和 Framework Crash(包含app crash在內(nèi))，對(duì)于Crash相信很多app開(kāi)發(fā)者都會(huì)遇到，那么上層什么時(shí)候會(huì)出現(xiàn)Crash呢，系統(tǒng)又是如何處理Crash的呢。例如，在app大家經(jīng)常使用try...catch語(yǔ)句，那么如果沒(méi)有有效catch exception，就是導(dǎo)致應(yīng)用Crash，發(fā)生沒(méi)有catch exception，系統(tǒng)便會(huì)來(lái)進(jìn)行捕獲，并進(jìn)入Crash流程。如果你是從事Android系統(tǒng)開(kāi)發(fā)或者架構(gòu)相關(guān)工作，或者遇到需要解系統(tǒng)性的疑難雜癥，那么很有必要了解系統(tǒng)Crash處理流程，知其然還需知其所以然；如果你僅僅是App初級(jí)開(kāi)發(fā)，可能本文并非很適合閱讀，整個(gè)系統(tǒng)流程錯(cuò)綜復(fù)雜。
在Android系統(tǒng)啟動(dòng)系列文章，已講述過(guò)上層應(yīng)用都是由Zygote fork孵化而來(lái)，分為system_server系統(tǒng)進(jìn)程和各種應(yīng)用進(jìn)程，在這些進(jìn)程創(chuàng)建之初會(huì)設(shè)置未捕獲異常的處理器，當(dāng)系統(tǒng)拋出未捕獲的異常時(shí)，最終都交給異常處理器。
- 對(duì)于system_server進(jìn)程：system_server啟動(dòng)過(guò)程中由RuntimeInit.java的commonInit方法設(shè)置UncaughtHandler，用于處理未捕獲異常；
- 對(duì)于普通應(yīng)用進(jìn)程：進(jìn)程創(chuàng)建過(guò)程中，同樣會(huì)調(diào)用RuntimeInit.java的commonInit方法設(shè)置UncaughtHandler。
1.1 crash調(diào)用鏈
crash流程的方法調(diào)用關(guān)系如下：
AMP.handleApplicationCrash AMS.handleApplicationCrash AMS.findAppProcess AMS.handleApplicationCrashInner AMS.addErrorToDropBox AMS.crashApplication AMS.makeAppCrashingLocked AMS.startAppProblemLocked ProcessRecord.stopFreezingAllLocked ActivityRecord.stopFreezingScreenLocked WMS.stopFreezingScreenLocked WMS.stopFreezingDisplayLocked AMS.handleAppCrashLocked mUiHandler.sendMessage(SHOW_ERROR_MSG) Process.killProcess(Process.myPid()); System.exit(10);
二、Crash處理流程
RuntimeInit.java類的 main方法會(huì)調(diào)用commonInit()方法。
public static final void main(String[] argv) {
enableDdms();
if (argv.length == 2 && argv[1].equals("application")) {
if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting application");
redirectLogStreams();
} else {
if (DEBUG) Slog.d(TAG, "RuntimeInit: Starting tool");
}
// AP Crash 處理流程初始化
commonInit();
// Native Crash 處理流程初始化
nativeFinishInit();
if (DEBUG) Slog.d(TAG, "Leaving RuntimeInit!");
}
那么接下來(lái)以commonInit()方法為起點(diǎn)來(lái)展開(kāi)說(shuō)明。
1. RuntimeInit.commonInit
RuntimeInit.java
protected static final void commonInit() {
/*
* set handlers; these apply to all threads in the VM. Apps can replace
* the default handler, but not the pre handler.
*/
LoggingHandler loggingHandler = new LoggingHandler();
// app不能 替換 setUncaughtExceptionPreHandler
Thread.setUncaughtExceptionPreHandler(loggingHandler);
// 將異常處理器handler對(duì)象賦給Thread成員變量,
Thread.setDefaultUncaughtExceptionHandler(new KillApplicationHandler(loggingHandler));
... ...
}
接下來(lái)我們看看LoggingHandler的實(shí)現(xiàn)。LoggingHandler實(shí)現(xiàn) Thread.UncaughtExceptionHandler 方法。
private static class LoggingHandler implements Thread.UncaughtExceptionHandler {
public volatile boolean mTriggered = false;
@Override
public void uncaughtException(Thread t, Throwable e) {
mTriggered = true;
//保證crash處理過(guò)程不會(huì)重入
if (mCrashing) return;
//mApplicationObject等于null,一定不是普通的app進(jìn)程.
//但是除了system進(jìn)程, 也有可能是shell進(jìn)程,
//即通過(guò)app_process + 命令參數(shù) 的方式創(chuàng)建的進(jìn)程.
if (mApplicationObject == null && (Process.SYSTEM_UID == Process.myUid())) {
//系統(tǒng) 進(jìn)程Crash打印的Log 信息
/**
發(fā)生 系統(tǒng)Crash 時(shí)候可以搜索 關(guān)鍵字 FATAL EXCEPTION IN SYSTEM PROCESS
**/
Clog_e(TAG, "*** FATAL EXCEPTION IN SYSTEM PROCESS: " + t.getName(), e);
} else {
/**
發(fā)生 APP Crash 時(shí)候可以搜索 關(guān)鍵字 FATAL EXCEPTION
**/
StringBuilder message = new StringBuilder();
message.append("FATAL EXCEPTION: ").append(t.getName()).append("n");
final String processName = ActivityThread.currentProcessName();
if (processName != null) {
message.append("Process: ").append(processName).append(", ");
}
message.append("PID: ").append(Process.myPid());
Clog_e(TAG, message.toString(), e);
}
}
}
- 1.當(dāng)System進(jìn)程Crash的信息：
開(kāi)頭 FATAL EXCEPTION IN SYSTEM PROCESS [線程名],接著輸出Crash時(shí)的調(diào)用棧信息；
- 2.當(dāng)app進(jìn)程Crash時(shí)的信息：
開(kāi)頭 FATAL EXCEPTION: [線程名],緊接著 Process: [進(jìn)程名], PID: [進(jìn)程id]；最后輸出發(fā)生Crash時(shí)的調(diào)用棧信息。
看到這里，你就會(huì)發(fā)現(xiàn)要從log中搜索Crash信息，只需要搜索關(guān)鍵詞 FATAL EXCEPTION,即可查看出是那種異常；如果需要進(jìn)一步篩選只搜索系統(tǒng)crash信息，則可以搜索的關(guān)鍵詞可以有多樣，比如 FATAL EXCEPTION IN SYSTEM PROCESS。
當(dāng)輸出完Crash信息到logcat里面，這只是Crash流程的剛開(kāi)始階段，接下來(lái)彈出Crash對(duì)話框，ActivityManagerNative.getDefault()返回的是ActivityManagerProxy（簡(jiǎn)稱AMP），AMP經(jīng)過(guò)binder調(diào)用最終交給ActivityManagerService(簡(jiǎn)稱AMS)中相應(yīng)的方法去處理,然后調(diào)用的是AMS.handleApplicationCrash()。
分析完LoggingHandler后，我們繼續(xù)看setDefaultUncaughtExceptionHandler()，它只是將異常處理器handler對(duì)象賦給Thread成員變量,即Thread.setDefaultUncaughtExceptionHandler(new KillApplicationHandler(loggingHandler));。接下來(lái)看看KillApplicationHandler對(duì)象實(shí)例化過(guò)程。
2. KillApplicationHandler
RuntimeInit.java
KillApplicationHandler 實(shí)現(xiàn) Thread.UncaughtExceptionHandler方法,主要處理由于未捕獲的異常Crash導(dǎo)致APP 崩潰,運(yùn)行在Main Thread的Framework 代碼會(huì)捕獲這些異常。
KillApplicationHandler 方法需要傳遞一個(gè)LoggingHandler的參數(shù)，
既 LoggingHandler loggingHandler = new LoggingHandler();，LoggingHandler在上文已經(jīng)分析過(guò)，接下來(lái)我們看看KillApplicationHandler方法.
KillApplicationHandler方法如下:
private static class KillApplicationHandler implements Thread.UncaughtExceptionHandler {
private final LoggingHandler mLoggingHandler;
public KillApplicationHandler(LoggingHandler loggingHandler) {
// 構(gòu)造方法，初始化 loggingHandler
this.mLoggingHandler = Objects.requireNonNull(loggingHandler);
}
@Override
public void uncaughtException(Thread t, Throwable e) {
try {
ensureLogging(t, e);
// 保證crash處理過(guò)程不會(huì)重入
if (mCrashing) return;
mCrashing = true;
... ...
//啟動(dòng)crash對(duì)話框，等待處理完成 【見(jiàn)小節(jié)2.1和3】
ActivityManager.getService().handleApplicationCrash(
mApplicationObject, new ApplicationErrorReport.ParcelableCrashInfo(e));
} catch (Throwable t2) {
... ...
} finally {
//確保當(dāng)前進(jìn)程徹底殺掉【見(jiàn)小節(jié)11】
Process.killProcess(Process.myPid());
System.exit(10);
}
}
... ...
}
接下來(lái)我們看看啟動(dòng)Crash彈窗的處理。new ApplicationErrorReport.ParcelableCrashInfo(e)方法。
2.1 ApplicationErrorReport.ParcelableCrashInfo
ApplicationErrorReport 主要用來(lái)描述 APP Error信息。
APP ERROR 信息分類如下：
- TYPE_CRASH： APP Crash 信息
- TYPE_ANR： APP ANR 信息
- TYPE_BATTERY： Battery 使用信息
- TYPE_RUNNING_SERVICE： 正在運(yùn)行的Service 相關(guān)信息
// 主要處理 APP Error 信息public class ApplicationErrorReport implements Parcelable { ... ... public static class ParcelableCrashInfo extends CrashInfo implements Parcelable { //創(chuàng)建 CrashInfo 實(shí)例，初始化異常信息 public ParcelableCrashInfo(Throwable tr) { super(tr); } ... ... public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
@Override
public ParcelableCrashInfo createFromParcel(Parcel in) {
return new ParcelableCrashInfo(in);
}
@Override
public ParcelableCrashInfo[] newArray(int size) {
return new ParcelableCrashInfo[size];
}
};
}
... ...
}
ParcelableCrashInfo 繼承 CrashInfo,接下來(lái)我們看看 CrashInfo的實(shí)現(xiàn)。
CrashInfo
**CrashInfo ** 主要是將Crash信息文件名，類名，方法名，對(duì)應(yīng)行號(hào)以及異常信息都封裝到CrashInfo對(duì)象。
// 描述 Crash 信息
public static class CrashInfo {
... ...
public CrashInfo() {
}
//CrashInfo 初始化實(shí)例
public CrashInfo(Throwable tr) {
StringWriter sw = new StringWriter();
PrintWriter pw = new FastPrintWriter(sw, false, 256);
//輸出棧trace
tr.printStackTrace(pw);
pw.flush();
stackTrace = sanitizeString(sw.toString());
exceptionMessage = tr.getMessage();
// 顯示異常的根本原因
Throwable rootTr = tr;
while (tr.getCause() != null) {
tr = tr.getCause();
if (tr.getStackTrace() != null && tr.getStackTrace().length > 0) {
rootTr = tr;
}
String msg = tr.getMessage();
if (msg != null && msg.length() > 0) {
exceptionMessage = msg;
}
}
// Crash 異常類名稱
exceptionClassName = rootTr.getClass().getName();
if (rootTr.getStackTrace().length > 0) {
StackTraceElement trace = rootTr.getStackTrace()[0];
// 獲取 trace 文件名、類名、方法名、Crash 行號(hào)
throwFileName = trace.getFileName();
throwClassName = trace.getClassName();
throwMethodName = trace.getMethodName();
throwLineNumber = trace.getLineNumber();
} else {
throwFileName = "unknown";
... ...
}
exceptionMessage = sanitizeString(exceptionMessage);
}
三、handleApplicationCrash處理分析
handleApplicationCrash 會(huì)通過(guò) JNI接口調(diào)用AMS中的方法。
//發(fā)送 Crash 彈窗handler，直到Dialog dismiss ActivityManager.getService().handleApplicationCrash( mApplicationObject, new ApplicationErrorReport.ParcelableCrashInfo(e));
ActivityManagerService.java
handleApplicationCrash 通過(guò)JNI 回調(diào)用 AMS中的handleApplicationCrash方法，進(jìn)而調(diào)用AMS 中的內(nèi)部方法handleApplicationCrashInner。
handleApplicationCrash
- 1.當(dāng)遠(yuǎn)程IBinder對(duì)象為空Null時(shí)，則進(jìn)程名為system_server；
- 2.當(dāng)遠(yuǎn)程IBinder對(duì)象不為空，且ProcessRecord為空時(shí)，則進(jìn)程名為unknown;
- 3.當(dāng)遠(yuǎn)程IBinder對(duì)象不為空，且ProcessRecord不為空時(shí)，則進(jìn)程名為ProcessRecord對(duì)象中相應(yīng)進(jìn)程名。
// 當(dāng)app Crash 時(shí)候，會(huì)調(diào)用此方法。
//調(diào)用結(jié)束后 ，app 進(jìn)程就會(huì)推出
public void handleApplicationCrash(IBinder app,
ApplicationErrorReport.ParcelableCrashInfo crashInfo) {
// findAppProcess 詳見(jiàn) 3.1 分析
ProcessRecord r = findAppProcess(app, "Crash");
// system_server 進(jìn)程 為Null
final String processName = app == null ? "system_server"
: (r == null ? "unknown" : r.processName);
//handleApplicationCrashInner 詳見(jiàn) 4 分析
handleApplicationCrashInner("crash", r, processName, crashInfo);
}
handleApplicationCrashInner主要是調(diào)用 AppErrors類中的crashApplication 方法處理。
void handleApplicationCrashInner(String eventType, ProcessRecord r, String processName,
ApplicationErrorReport.CrashInfo crashInfo) {
... ...
//調(diào)用APP Error 類方法中的 crashApplication
mAppErrors.crashApplication(r, crashInfo);
}
3.1 findAppProcess
ActivityManagerService.java
findAppProcess主要是通過(guò)for循環(huán)遍歷查找出IBinder對(duì)應(yīng)的Process.
private ProcessRecord findAppProcess(IBinder app, String reason) { ... ... synchronized (this) { final int NP = mProcessNames.getMap().size(); for (int ip=0; ip apps = mProcessNames.getMap().valueAt(ip); final int NA = apps.size(); for (int ia=0; ia ProcessRecord p = apps.valueAt(ia);
//當(dāng)找到目標(biāo)進(jìn)程則返回
if (p.thread != null && p.thread.asBinder() == app) {
return p;
}
}
}
//如果代碼執(zhí)行到這里，表明無(wú)法找到應(yīng)用所在的進(jìn)程
return null;
}
}
其中 mProcessNames = new ProcessMap();對(duì)于代碼mProcessNames.getMap()返回的是mMap，而mMap= new ArrayMap>();
知識(shí)延伸：SparseArray和ArrayMap是Android專門(mén)針對(duì)內(nèi)存優(yōu)化而設(shè)計(jì)的取代Java API中的HashMap的數(shù)據(jù)結(jié)構(gòu)。
對(duì)于key是int類型則使用SparseArray，可避免自動(dòng)裝箱過(guò)程；
對(duì)于key為其他類型則使用ArrayMap。
HashMap的查找和插入時(shí)間復(fù)雜度為O(1)的代價(jià)是犧牲大量的內(nèi)存來(lái)實(shí)現(xiàn)的，而SparseArray和ArrayMap性能略遜于HashMap，但更節(jié)省內(nèi)存。
再回到mMap，這是以進(jìn)程name為key，再以(uid為key，以ProcessRecord為Value的)結(jié)構(gòu)體作為value。下面看看其get()和put()方法
public E get(String name, int uid) { SparseArray uids = mMap.get(name); if (uids == null) return null; return uids.get(uid); } public E put(String name, int uid, E value) { SparseArray uids = mMap.get(name); if (uids == null) { uids = new SparseArray(2);
mMap.put(name, uids);
}
uids.put(uid, value);
return value;
}
findAppProcess()根據(jù)app(IBinder類型)來(lái)查詢相應(yīng)的目標(biāo)對(duì)象ProcessRecord。
有了進(jìn)程記錄對(duì)象ProcessRecord和進(jìn)程名processName，則進(jìn)入執(zhí)行Crash處理方法 AppErrors.java，繼續(xù)往下看。
四、handleApplicationCrashInner 處理分析
ActivityManagerService.java
void handleApplicationCrashInner(String eventType, ProcessRecord r, String processName,
ApplicationErrorReport.CrashInfo crashInfo) {
... ...
//將錯(cuò)誤信息追加到DropBox
addErrorToDropBox(eventType, r, processName, null, null, null, null, null, crashInfo);
//【見(jiàn)小節(jié)5】
mAppErrors.crashApplication(r, crashInfo);
}
其中addErrorToDropBox是將Crash的信息輸出到目錄/data/system/dropbox。例如system_server的dropbox文件名為[email protected] (xxx代表的是時(shí)間戳)
五、APP Error info分析
AppErrors.java
AppErrors 主要是 控制APP Crash的場(chǎng)景條件。
void crashApplication(ProcessRecord r, ApplicationErrorReport.CrashInfo crashInfo) {
... ...
try {
// 調(diào)用內(nèi)部 crashApplicationInner方法
crashApplicationInner(r, crashInfo, callingPid, callingUid);
} finally {
Binder.restoreCallingIdentity(origId);
}
}
crashApplicationInner內(nèi)部方法
void crashApplicationInner(ProcessRecord r, ApplicationErrorReport.CrashInfo crashInfo,
int callingPid, int callingUid) {
... ...
AppErrorResult result = new AppErrorResult();
TaskRecord task;
synchronized (mService) {
// 如果是通過(guò)IActivityController 實(shí)例導(dǎo)致的Crash ，則不顯示彈窗
// 詳見(jiàn)5.1
if (handleAppCrashInActivityController(r, crashInfo, shortMsg, longMsg, stackTrace,
timeMillis, callingPid, callingUid)) {
return;
}
... ...
AppErrorDialog.Data data = new AppErrorDialog.Data();
data.result = result;
data.proc = r;
// 無(wú)法勢(shì)必的進(jìn)程 也不顯示Crash 彈窗【見(jiàn)小節(jié)6】
if (r == null || !makeAppCrashingLocked(r, shortMsg, longMsg, stackTrace, data)) {
return;
}
final Message msg = Message.obtain();
msg.what = ActivityManagerService.SHOW_ERROR_UI_MSG;
task = data.task;
msg.obj = data;
//發(fā)送消息SHOW_ERROR_MSG，彈出提示crash的對(duì)話框，等待用戶選擇【見(jiàn)小節(jié)10】
mService.mUiHandler.sendMessage(msg);
}
//進(jìn)入阻塞等待，直到用戶選擇crash對(duì)話框"退出"或者"退出并報(bào)告"
int res = result.get();
Intent appErrorIntent = null;
MetricsLogger.action(mContext, MetricsProto.MetricsEvent.ACTION_APP_CRASH, res);
if (res == AppErrorDialog.TIMEOUT || res == AppErrorDialog.CANCEL) {
res = AppErrorDialog.FORCE_QUIT;
}
... ...
}
5.1 handleAppCrashInActivityController
handleAppCrashInActivityController,通過(guò)IActivityController 實(shí)例導(dǎo)致的Crash ，則不顯示彈窗.
AppError.java
private boolean handleAppCrashInActivityController(ProcessRecord r,
ApplicationErrorReport.CrashInfo crashInfo,
String shortMsg, String longMsg,
String stackTrace, long timeMillis,
int callingPid, int callingUid) {
... ...
// 當(dāng)存在ActivityController的情況,比如monkey
try {
String name = r != null ? r.processName : null;
int pid = r != null ? r.pid : callingPid;
int uid = r != null ? r.info.uid : callingUid;
//調(diào)用monkey的 appCrashed
if (!mService.mController.appCrashed(name, pid,
shortMsg, longMsg, timeMillis, crashInfo.stackTrace)) {
if ("1".equals(SystemProperties.get(SYSTEM_DEBUGGABLE, "0"))
&& "Native crash".equals(crashInfo.exceptionClassName)) {
Slog.w(TAG, "Skip killing native crashed app " + name
+ "(" + pid + ") during testing");
} else {
Slog.w(TAG, "Force-killing crashed app " + name
+ " at watcher's request");
if (r != null) {
//調(diào)用`makeAppCrashingLocked`，繼續(xù)處理crash流程
// 詳見(jiàn) 小結(jié) 6
if (!makeAppCrashingLocked(r, shortMsg, longMsg, stackTrace, null))
{
r.kill("crash", true);
}
} else {
// Huh.
Process.killProcess(pid);
ActivityManagerService.killProcessGroup(uid, pid);
}
}
return true;
}
} catch (RemoteException e) {
mService.mController = null;
Watchdog.getInstance().setActivityController(null);
}
return false;
}
該方法主要做的兩件事：
- 調(diào)用makeAppCrashingLocked，繼續(xù)處理Crash流程；
- 發(fā)送消息SHOW_ERROR_MSG，彈出提示Crash的對(duì)話框，等待用戶選擇；
接下來(lái)我們看makeAppCrashingLocked實(shí)現(xiàn)。
六、makeAppCrashingLocked處理分析
AppError.java
private boolean makeAppCrashingLocked(ProcessRecord app,
String shortMsg, String longMsg, String stackTrace, AppErrorDialog.Data data) {
app.crashing = true;
//封裝crash信息到crashingReport對(duì)象
app.crashingReport = generateProcessError(app,
ActivityManager.ProcessErrorStateInfo.CRASHED, null, shortMsg, longMsg, stackTrace);
//【見(jiàn)小節(jié)7】
startAppProblemLocked(app);
//停止屏幕凍結(jié)【見(jiàn)小節(jié)8】
app.stopFreezingAllLocked();
//【見(jiàn)小節(jié)9】
return handleAppCrashLocked(app, "force-crash" /*reason*/, shortMsg, longMsg, stackTrace,
data);
}
七、startAppProblemLocked處理分析
AppError.java
startAppProblemLocked 該方法主要功能：
- 獲取當(dāng)前用戶下的crash應(yīng)用的error receiver；
- 忽略當(dāng)前App的廣播接收；
void startAppProblemLocked(ProcessRecord app) {
// 如果不是當(dāng)前user正在運(yùn)行 app，這置為空
app.errorReportReceiver = null;
for (int userId : mService.mUserController.getCurrentProfileIds()) {
if (app.userId == userId) {
//獲取當(dāng)前用戶下的crash應(yīng)用的error receiver【見(jiàn)小節(jié)7.1】
app.errorReportReceiver = ApplicationErrorReport.getErrorReportReceiver(
mContext, app.info.packageName, app.info.flags);
}
}
//忽略當(dāng)前app的廣播接收【見(jiàn)小節(jié)7.2】
mService.skipCurrentReceiverLocked(app);
}
7.1 getErrorReportReceiver
ApplicationErrorReport.java
獲取當(dāng)前用戶下的Crash應(yīng)用的error receiver
public static ComponentName getErrorReportReceiver(Context context,
String packageName, int appFlags) {
//檢查Settings中的"send_action_app_error"是否使能錯(cuò)誤報(bào)告的功能
int enabled = Settings.Global.getInt(context.getContentResolver(),
Settings.Global.SEND_ACTION_APP_ERROR, 0);
if (enabled == 0) {
//1.當(dāng)未使能時(shí)，則直接返回
return null;
}
PackageManager pm = context.getPackageManager();
// look for receiver in the installer package
String candidate = null;
ComponentName result = null;
try {
//獲取該crash應(yīng)用的安裝器的包名
candidate = pm.getInstallerPackageName(packageName);
} catch (IllegalArgumentException e) {
// the package could already removed
}
if (candidate != null) {
result = getErrorReportReceiver(pm, packageName, candidate);
if (result != null) {
//2.當(dāng)找到該crash應(yīng)用的安裝器，則返回；
return result;
}
}
//該系統(tǒng)屬性名為"ro.error.receiver.system.apps"
if ((appFlags&ApplicationInfo.FLAG_SYSTEM) != 0) {
candidate = SystemProperties.get(SYSTEM_APPS_ERROR_RECEIVER_PROPERTY);
// 通過(guò)上下文對(duì)象傳參，調(diào)用類內(nèi)部方法
result = getErrorReportReceiver(pm, packageName, candidate);
if (result != null) {
//3.當(dāng)crash應(yīng)用是系統(tǒng)應(yīng)用時(shí)，且系統(tǒng)屬性指定error receiver時(shí)，則返回；
return result;
}
}
//該默認(rèn)屬性名為"ro.error.receiver.default"
candidate = SystemProperties.get(DEFAULT_ERROR_RECEIVER_PROPERTY);
//4.當(dāng)默認(rèn)屬性值指定error receiver時(shí)，則返回；
return getErrorReportReceiver(pm, packageName, candidate);
}
getErrorReportReceiver：這是同名不同輸入?yún)?shù)的另一個(gè)方法：
static ComponentName getErrorReportReceiver(PackageManager pm, String errorPackage,
String receiverPackage) {
if (receiverPackage == null || receiverPackage.length() == 0) {
return null;
}
//當(dāng)安裝應(yīng)用程序的安裝器Crash，則直接返回
if (receiverPackage.equals(errorPackage)) {
return null;
}
//ACTION_APP_ERROR值為"android.intent.action.APP_ERROR"
Intent intent = new Intent(Intent.ACTION_APP_ERROR);
intent.setPackage(receiverPackage);
ResolveInfo info = pm.resolveActivity(intent, 0);
if (info == null || info.activityInfo == null) {
return null;
}
//創(chuàng)建包名為receiverPackage的組件
return new ComponentName(receiverPackage, info.activityInfo.name);
}
7.2 skipCurrentReceiverLocked
ActivityManagerService.java
忽略當(dāng)前app的廣播接收
void skipCurrentReceiverLocked(ProcessRecord app) {
for (BroadcastQueue queue : mBroadcastQueues) {
// 會(huì)調(diào)用BroadcastQueue 中的方法【見(jiàn)小節(jié)7.2.1】
queue.skipCurrentReceiverLocked(app);
}
}
7.2.1 skipCurrentReceiverLocked
BroadcastQueue.java skipCurrentReceiverLocked忽略當(dāng)前app的廣播接收.
public void skipCurrentReceiverLocked(ProcessRecord app) {
BroadcastRecord r = null;
//查看app進(jìn)程中的廣播
if (mOrderedBroadcasts.size() > 0) {
BroadcastRecord br = mOrderedBroadcasts.get(0);
// 判斷是否一致
if (br.curApp == app) {
r = br;
}
}
... ...
if (r != null) {
// 見(jiàn)7.2.2
skipReceiverLocked(r);
}
}
7.2.2 skipReceiverLocked
BroadcastQueue.java
private void skipReceiverLocked(BroadcastRecord r) {
logBroadcastReceiverDiscardLocked(r);
//結(jié)束app進(jìn)程的廣播結(jié)束
finishReceiverLocked(r, r.resultCode, r.resultData,
r.resultExtras, r.resultAbort, false);
//執(zhí)行廣播調(diào)度
scheduleBroadcastsLocked();
}
八、stopFreezingAllLocked處理分析
AppError.java中的 makeAppCrashingLocked方法（第6步），會(huì)調(diào)用stopFreezingAllLocked 方法
ProcessRecord.java
public void stopFreezingAllLocked() {
int i = activities.size();
while (i > 0) {
i--;
// 停止進(jìn)程里所有的`Activity`. 詳見(jiàn)8.1
activities.get(i).stopFreezingScreenLocked(true);
}
}
其中activities類型為ArrayList，停止進(jìn)程里所有的Activity.
8.1 AR.stopFreezingScreenLocked
ActivityRecord.java,stopFreezingScreenLocked停止進(jìn)程里所有的Activity.
public void stopFreezingScreenLocked(boolean force) {
if (force || frozenBeforeDestroy) {
frozenBeforeDestroy = false;
// mWindowContainerController 見(jiàn)【8.1.1】
mWindowContainerController.stopFreezingScreen(force);
}
}
8.1.1mWindowContainerController.stopFreezingScreen
stopFreezingScreen.java
public void stopFreezingScreen(boolean force) {
synchronized(mWindowMap) {
if (mContainer == null) {
return;
}
if (DEBUG_ORIENTATION) Slog.v(TAG_WM, "Clear freezing of " + mToken + ": hidden="
+ mContainer.isHidden() + " freezing=" + mContainer.isFreezingScreen());
mContainer.stopFreezingScreen(true, force);
}
}
8.1.1.1 WMS.stopFreezingScreenLocked
WindowManagerService.java
@Override
public void stopFreezingScreen() {
... ...
synchronized(mWindowMap) {
if (mClientFreezingScreen) {
mClientFreezingScreen = false;
mLastFinishedFreezeSource = "client";
final long origId = Binder.clearCallingIdentity();
try {
// 詳見(jiàn) 8.1.1.2
stopFreezingDisplayLocked();
} finally {
Binder.restoreCallingIdentity(origId);
}
}
}
}
8.1.1.2 stopFreezingDisplayLocked();
WindowManagerService.java
該方法主要功能：
處理屏幕旋轉(zhuǎn)相關(guān)邏輯；
移除凍屏的超時(shí)消息；
屏幕旋轉(zhuǎn)動(dòng)畫(huà)的相關(guān)操作;
使能輸入事件分發(fā)功能；
display凍結(jié)時(shí)，執(zhí)行g(shù)c操作；
更新當(dāng)前的屏幕方向；
向mH發(fā)送configuraion改變的消息
rivate void stopFreezingDisplayLocked() {
if (!mDisplayFrozen) {
return; //顯示沒(méi)有凍結(jié)，則直接返回
}
//往往跟屏幕旋轉(zhuǎn)相關(guān)
...
mDisplayFrozen = false;
//從上次凍屏到現(xiàn)在的總時(shí)長(zhǎng)
mLastDisplayFreezeDuration = (int)(SystemClock.elapsedRealtime() - mDisplayFreezeTime);
//移除凍屏的超時(shí)消息
mH.removeMessages(H.APP_FREEZE_TIMEOUT);
mH.removeMessages(H.CLIENT_FREEZE_TIMEOUT);
boolean updateRotation = false;
//獲取默認(rèn)的DisplayContent
final DisplayContent displayContent = getDefaultDisplayContentLocked();
final int displayId = displayContent.getDisplayId();
ScreenRotationAnimation screenRotationAnimation =
mAnimator.getScreenRotationAnimationLocked(displayId);
//屏幕旋轉(zhuǎn)動(dòng)畫(huà)的相關(guān)操作
if (CUSTOM_SCREEN_ROTATION && screenRotationAnimation != null
&& screenRotationAnimation.hasScreenshot()) {
DisplayInfo displayInfo = displayContent.getDisplayInfo();
boolean isDimming = displayContent.isDimming();
if (!mPolicy.validateRotationAnimationLw(mExitAnimId, mEnterAnimId, isDimming)) {
mExitAnimId = mEnterAnimId = 0;
}
//加載動(dòng)畫(huà)最大時(shí)長(zhǎng)為10s
if (screenRotationAnimation.dismiss(mFxSession, MAX_ANIMATION_DURATION,
getTransitionAnimationScaleLocked(), displayInfo.logicalWidth,
displayInfo.logicalHeight, mExitAnimId, mEnterAnimId)) {
scheduleAnimationLocked();
} else {
screenRotationAnimation.kill();
mAnimator.setScreenRotationAnimationLocked(displayId, null);
updateRotation = true;
}
} else {
if (screenRotationAnimation != null) {
screenRotationAnimation.kill();
mAnimator.setScreenRotationAnimationLocked(displayId, null);
}
updateRotation = true;
}
//經(jīng)過(guò)層層調(diào)用到InputManagerService服務(wù)，IMS服務(wù)使能輸入事件分發(fā)功能
mInputMonitor.thawInputDispatchingLw();
boolean configChanged;
//當(dāng)display被凍結(jié)時(shí)不再計(jì)算屏幕方向，以避免不連續(xù)的狀態(tài)。
configChanged = updateOrientationFromAppTokensLocked(false);
//display凍結(jié)時(shí)，執(zhí)行g(shù)c操作
mH.removeMessages(H.FORCE_GC);
mH.sendEmptyMessageDelayed(H.FORCE_GC, 2000);
//mScreenFrozenLock的類型為PowerManager.WakeLock，即釋放屏幕凍結(jié)的鎖
mScreenFrozenLock.release();
if (updateRotation) {
//更新當(dāng)前的屏幕方向
configChanged |= updateRotationUncheckedLocked(false);
}
if (configChanged) {
//向mH發(fā)送configuraion改變的消息
mH.sendEmptyMessage(H.SEND_NEW_CONFIGURATION);
}
}
