在上一篇文章《Android源碼剖析：基于 Handler掘宪、Looper 實現(xiàn)攔截全局崩潰攘烛、監(jiān)控ANR等》介紹了如何實現(xiàn)簡單的ANR監(jiān)控鼠次，判斷是否出現(xiàn)了ANR觅捆，但是沒有介紹如何分析栅炒，這篇文章將會詳細介紹如何分析解決ANR問題职辅。

觸發(fā) ANR

1. 5s內(nèi)無法響應用戶輸入事件(例如鍵盤輸入, 觸摸屏幕等)
2. BroadcastReceiver在10s內(nèi)無法結束
3. Service在特定的時間內(nèi)無法處理完成

檢測是否存在ANR

class MyApplication : Application() {
    override fun onCreate() {
        super.onCreate()
        var startWorkTimeMillis = 0L
        Looper.getMainLooper().setMessageLogging {
            if (it.startsWith(">>>>> Dispatching to Handler")) {
                startWorkTimeMillis = System.currentTimeMillis()
            } else if (it.startsWith("<<<<< Finished to Handler")) {
                val duration = System.currentTimeMillis() - startWorkTimeMillis
                if (duration > 500) {
                    Log.e("主線程執(zhí)行耗時過長","$duration 毫秒簇秒，$it")
                }
            }
        }
    }
}

通過上述代碼可以檢測是否執(zhí)行耗時過長趋观，當出現(xiàn)ANR的時候皱坛，ANR執(zhí)行超過5秒，系統(tǒng)會把堆棧打印在/data/anr/traces.txt。

獲取trace.txt 文件

adb shell cat /data/anr/traces.txt > d:/traces.txt

但是這種方式?jīng)]有辦法做檢測吭服，沒辦法上報到服務端艇棕，無法協(xié)助我們遠程分析問題北苟。

通過代碼獲取出現(xiàn) ANR 堆棧

class MyApplication : Application() {
    private val TAG = "MyApplication"
    private var startWorkTimeMillis = 0L
    private val mRunnable = Runnable {
        // 獲取主線程
        val thread = Looper.getMainLooper().thread
        val stringBuilder = StringBuilder()
        // 打印主線程的堆棧
        for (stack in thread.stackTrace) {
            stringBuilder.append(stack).append('\n')
        }
        Log.e("耗時過長", stringBuilder.toString())
    }

    override fun onCreate() {
        super.onCreate()

        val handlerThread = HandlerThread("anr")
        handlerThread.start()
        val stackHandler = Handler(handlerThread.looper)

        Looper.getMainLooper().setMessageLogging {
            if (it.startsWith(">>>>> Dispatching to Handler")) {
                startWorkTimeMillis = System.currentTimeMillis()
                stackHandler.removeCallbacks(mRunnable)
                stackHandler.postDelayed(mRunnable, 500)
            } else if (it.startsWith("<<<<< Finished to Handler")) {
                stackHandler.removeCallbacks(mRunnable)
                val duration = System.currentTimeMillis() - startWorkTimeMillis
                if (duration > 500) {
                    Log.e("主線程執(zhí)行耗時過長", "$duration 毫秒桃移，$it")
                }
            }
        }
    }
}

模擬測試

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        button1.setOnClickListener {
            Thread.sleep(1000)
        }
        button2.setOnClickListener {
            Thread.sleep(5000)
            Thread(Runnable {
                throw RuntimeException()
            }).start()
        }
    }
}

測試結果

E/耗時過長: java.lang.Thread.sleep(Native Method)
    java.lang.Thread.sleep(Thread.java:373)
    java.lang.Thread.sleep(Thread.java:314)
    com.taoweiji.handleranalyze.MainActivity$onCreate$1.onClick(MainActivity.kt:18)
    android.view.View.performClick(View.java:6597)
    android.view.View.performClickInternal(View.java:6574)
    android.view.View.access$3100(View.java:778)
    android.view.View$PerformClick.run(View.java:25885)
    android.os.Handler.handleCallback(Handler.java:873)
    android.os.Handler.dispatchMessage(Handler.java:99)
    android.os.Looper.loop(Looper.java:193)
    android.app.ActivityThread.main(ActivityThread.java:6669)
    java.lang.reflect.Method.invoke(Native Method)
    com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
    com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
E/主線程執(zhí)行耗時過長: 1003 毫秒进泼，<<<<< Finished to Handler (android.view.ViewRootImpl$ViewRootHandler) {5dddc1b} android.view.View$PerformClick@b1d8dda

總結

通過上述代碼可以獲取ANR绞惦，打印堆棧信息济蝉，但是并不能獲取所有情況的ANR王滤，比如CPU計算資源耗盡導致整個APP所有線程都卡死雁乡，這種情況下是解決不了。