1) ANR一般有三种类型：
1：KeyDispatchTimeout(5 seconds) --主要类型
按键或触摸事件在特定时间内无响应
2：BroadcastTimeout(10 seconds)
BroadcastReceiver在特定时间内无法处理完成
3：ServiceTimeout(20 seconds) --小概率类型
Service在特定的时间内无法处理完成
2) KeyDispatchTimeout
按键或者触摸事件在规定时间内没有响应。具体的超时时间的定义在framework下的ActivityManagerService.java
3) 超时原因：
超时的计数一般从按键分发给app开始。
(1)当前的事件没有机会得到处理（即UI线程正在处理前一个事件，没有及时的完成或者looper被某种原因阻塞住了）
(2)当前的事件正在处理，但没有及时完成
4)如何避免KeyDispatchTimeout
1：UI线程尽量只做跟UI相关的工作
2：耗时的工作（比如数据库操作，I/O，连接网络或者别的有可能阻碍UI线程的操作）把它放入单独的线程处理
3：尽量用Handler来处理UIthread和别的thread之间的交互
5) UI线程
哪些属于UI线程呢？
UI线程主要包括如下：
Activity:onCreate(), onResume(), onDestroy(), onKeyDown(), onClick(),etc
AsyncTask: onPreExecute(), onProgressUpdate(), onPostExecute(), onCancel,etc
Mainthread handler: handleMessage(), post*(runnable r), etc
other
6) 分析ANR
如果CPU使用率很高，可能是当前app获取不到CPU使用权导致的饥饿现象或者在大量计算死锁了。
如果CPU使用率低，主线程BLOCK了
IOwait很高，说明ANR很可能是IO导致的。
这是通过logcat分析出来的
7) 快速解决小技巧
1.以项目的包名中的关键字进行搜索
2.搜索可能导致ANR的的关键字：block,iowait,
8) JAVA中的线程的状态
public enum State { /** * The thread has been created, but has never been started. */ NEW, /** * The thread may be run. */ RUNNABLE, /** * The thread is blocked and waiting for a lock. */ BLOCKED, /** * The thread is waiting. */ WAITING, /** * The thread is waiting for a specified amount of time. */ TIMED_WAITING, /** * The thread has been terminated. */ TERMINATED }
9) C代码中定义的线程的状态
// /art/runtime/thread_state.h
enum ThreadState {
// Thread.State JDWP state
kTerminated = 66, // TERMINATED TS_ZOMBIE Thread.run has returned, but Thread* still around
kRunnable, // RUNNABLE TS_RUNNING runnable
kTimedWaiting, // TIMED_WAITING TS_WAIT in Object.wait() with a timeout
kSleeping, // TIMED_WAITING TS_SLEEPING in Thread.sleep()
kBlocked, // BLOCKED TS_MONITOR blocked on a monitor
kWaiting, // WAITING TS_WAIT in Object.wait()
kWaitingForGcToComplete, // WAITING TS_WAIT blocked waiting for GC
kWaitingForCheckPointsToRun, // WAITING TS_WAIT GC waiting for checkpoints to run
kWaitingPerformingGc, // WAITING TS_WAIT performing GC
kWaitingForDebuggerSend, // WAITING TS_WAIT blocked waiting for events to be sent
kWaitingForDebuggerToAttach, // WAITING TS_WAIT blocked waiting for debugger to attach
kWaitingInMainDebuggerLoop, // WAITING TS_WAIT blocking/reading/processing debugger events
kWaitingForDebuggerSuspension, // WAITING TS_WAIT waiting for debugger suspend all
kWaitingForJniOnLoad, // WAITING TS_WAIT waiting for execution of dlopen and JNI on load code
kWaitingForSignalCatcherOutput, // WAITING TS_WAIT waiting for signal catcher IO to complete
kWaitingInMainSignalCatcherLoop, // WAITING TS_WAIT blocking/reading/processing signals
kWaitingForDeoptimization, // WAITING TS_WAIT waiting for deoptimization suspend all
kWaitingForMethodTracingStart, // WAITING TS_WAIT waiting for method tracing to start
kWaitingForVisitObjects, // WAITING TS_WAIT waiting for visiting objects
kWaitingForGetObjectsAllocated, // WAITING TS_WAIT waiting for getting the number of allocated objects
kStarting, // NEW TS_WAIT native thread started, not yet ready to run managed code
kNative, // RUNNABLE TS_RUNNING running in a JNI native method
kSuspended, // RUNNABLE TS_RUNNING suspended by GC or debugger
};
两者可以看出在C代码中定义更为详细,Traces中显示的线程状态都是C代码定义的.我们可以通过查看线程状态对应的信息分析ANR问题.
