Android ANR 分析与解决

• 今天解决了一个ANR异常问题，心情愉悦，原来ANR分析解决很简单（可能问题本来比较简单吧~~暂做参考）

三个步骤搞定：

步骤一：重现ANR 异常

对着界面一顿操作...直至弹出anr提示

步骤二：拉取anr log文件

adb shell                                       //进入shell命令模式
cp data/anr/traces.txt sdcard/traces.txt        //将traces.txt文件copy到sdcard

步骤三：分析ANR日志：

1.打开traces.txt

tips：可以将文件重命名为.log的文件，然后再vscode打开，这样有颜色。

2.直接搜索关键词：DALVIK THREADS，然后查看 tid=1的"main"线程。

如果你用vscode打开该log文件，会看到类似于logcat的一堆：

 at android.os.BinderProxy.transactNative(Native method)
  at android.os.BinderProxy.transact(Binder.java:615)
  at android.bluetooth.IBluetooth$Stub$Proxy.getRemoteName(IBluetooth.java:1351)
  at android.bluetooth.BluetoothDevice.getName(BluetoothDevice.java:731)
  at akw$5.onLeScan(BluetoothLeDevice.java:263)
  at android.bluetooth.BluetoothAdapter$2.onScanResult(BluetoothAdapter.java:2388)
  at android.bluetooth.le.BluetoothLeScanner$BleScanCallbackWrapper$1.run(BluetoothLeScanner.java:400)
  at android.os.Handler.handleCallback(Handler.java:751)
  at android.os.Handler.dispatchMessage(Handler.java:95)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6244)
  at java.lang.reflect.Method.invoke!(Native method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:797)

3.找到属于你的项目的那个java文件，定位到出毛病的那一行。

4.接下来就是去自己的代码中分析了，如果你知道ANR的理论知识，分析解决，应该不是难事。

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============割==============

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举个栗子：

在我的项目中，蓝牙扫描的同时绘制地图，出现了ANR，在部分手机可复现，于是按照上述步骤一顿操作，得到ANR日志文件如下（关键部分）：

TIM图片20180810105209.png

 
  at android.bluetooth.IBluetooth$Stub$Proxy.getRemoteName(IBluetooth.java:1351)
  at android.bluetooth.BluetoothDevice.getName(BluetoothDevice.java:731)
  at akw$5.onLeScan(BluetoothLeDevice.java:263)
  at android.bluetooth.BluetoothAdapter$2.onScanResult(BluetoothAdapter.java:2388)
  at android.bluetooth.le.BluetoothLeScanner$BleScanCallbackWrapper$1.run(BluetoothLeScanner.java:400)
  at android.os.Handler.handleCallback(Handler.java:751)
  at android.os.Handler.dispatchMessage(Handler.java:95)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6244)
  at java.lang.reflect.Method.invoke!(Native method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:797)


#================省略其他线程===================

----- end 9155 -----

可以看出，问题出在调用BluetoothDevice.getName()方法上，自己的代码的问题出在(BluetoothLeDevice.java:263)。这个类是自己写的。进去看一下代码：

//class:BluetoothLeDevice.java
mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

            @Override
            public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
                    mScanTimes++;
                String carBleName = getCarBleName();
                String carOrgBleName = getCarBleOrgName();
                String carBleMac = getCarBleMac();
                if (BuildConfig.DEBUG)
                    Log.i(TAG, "LeScanCallback " + device.getName() + " ?= " + carBleName + " | " + carOrgBleName + " mac:" + device.getAddress() + " ?= " + carBleMac + " " + mScanTimes);
                else
                    Log.i(TAG, "LeScanCallback name:" + device.getName() + " mac:" + device.getAddress() + " ?= " + carBleMac + " " + mScanTimes);
                if ((carBleMac != null && device.getAddress() != null 
                        && !TextUtils.isEmpty(carBleMac.trim()) 
                        && device.getAddress().equals(carBleMac.trim())) ||     //这一坨就是第263行
                        (carBleName != null && device.getName() != null 
                                && !TextUtils.isEmpty(carBleName.trim())
                                && device.getName().equals(carBleName.trim())) ||
                        (carOrgBleName != null && device.getName() != null
                                && !TextUtils.isEmpty(carOrgBleName.trim()) 
                                && device.getName().equals(carOrgBleName.trim()))) {
                    Log.i(TAG, "LeScanCallback found " + device.getName() + " mac:" + device.getAddress());
                    postHandlerEvent(new BlueToothMatch(device.getName(), device.getAddress()));
            }
        };

在第263行，扫描蓝牙的时候，进行了一坨判断，判断里进行了好多次的getName方法，然后postHandle....
这就是问题所在了。解决后：

  mLeScanCallback = new BluetoothAdapter.LeScanCallback() {

            @Override
            public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
                    mScanTimes++;
                String carBleName = getCarBleName();
                String carOrgBleName = getCarBleOrgName();
                String carBleMac = getCarBleMac();
                String deviceName = device.getName();//在此处获取一次就行了
                String deviceAddress = device.getAddress();
                
                if (BuildConfig.DEBUG)
                    Log.i(TAG, "LeScanCallback " + deviceName + " ?= " + carBleName + " | " + carOrgBleName + " mac:" + device.getAddress() + " ?= " + carBleMac + " " + mScanTimes);
                else
                    Log.i(TAG, "LeScanCallback name:" + deviceName + " mac:" + deviceAddress + " ?= " + carBleMac + " " + mScanTimes);
                if ((carBleMac != null && deviceAddress != null && !TextUtils.isEmpty(carBleMac.trim()) && deviceAddress.equals(carBleMac.trim())) ||
                        (carBleName != null && deviceName != null && !TextUtils.isEmpty(carBleName.trim()) && deviceName.equals(carBleName.trim())) ||
                        (carOrgBleName != null && deviceName != null && !TextUtils.isEmpty(carOrgBleName.trim()) && deviceName.equals(carOrgBleName.trim()))) {
                    Log.i(TAG, "LeScanCallback found " + deviceName + " mac:" + deviceAddress);
                    postHandlerEvent(new BlueToothMatch(deviceName, deviceAddress));
            }
        };