背景

公司测试人发现在监听传感器界面界面就有可能出现anr

问题重现

导出手机的anr日记，打印如下

"main" prio=5 tid=1 Native
  | group="main" sCount=1 dsCount=0 flags=1 obj=0x752b5050 self=0xf0d44000
  | sysTid=24817 nice=-10 cgrp=default sched=0/0 handle=0xf5572494
  | state=S schedstat=( 13809870839 1897535961 16257 ) utm=1153 stm=227 core=3 HZ=100
  | stack=0xff2f5000-0xff2f7000 stackSize=8MB
  | held mutexes=
  kernel: (couldn't read /proc/self/task/24817/stack stderr:Permission denied)
  native: #00 pc 0005597c  /system/lib/libc.so (__ioctl+8)
  native: #01 pc 00022593  /system/lib/libc.so (ioctl+38)
  native: #02 pc 0004c40b  /system/lib/libbinder.so (android::IPCThreadState::talkWithDriver(bool)+206)
  native: #03 pc 0004d223  /system/lib/libbinder.so (android::IPCThreadState::waitForResponse(android::Parcel*, int*)+26)
  native: #04 pc 0004cf71  /system/lib/libbinder.so (android::IPCThreadState::transact(int, unsigned int, android::Parcel const&, android::Parcel*, unsigned int)+164)
  native: #05 pc 00045d21  /system/lib/libbinder.so (android::BpBinder::transact(unsigned int, android::Parcel const&, android::Parcel*, unsigned int)+36)
  native: #06 pc 000cc48b  /system/lib/libandroid_runtime.so (android_os_BinderProxy_transact(_JNIEnv*, _jobject*, int, _jobject*, _jobject*, int)+306)
  at android.os.BinderProxy.transactNative(Native method)
  at android.os.BinderProxy.transact(Binder.java:1149)
  at android.media.IAudioService$Stub$Proxy.setMode(IAudioService.java:1445)
  at android.media.AudioManager.setMode(AudioManager.java:1890)
  at 公司包名.activities.ChatActivityV2.changeAudioType(ChatActivityV2.java:2848)
  at 公司包名.activities.ChatActivityV2.access$3200(ChatActivityV2.java:179)
  at 公司包名.activities.ChatActivityV2$42.onSensorChanged(ChatActivityV2.java:2826)
  at android.hardware.SystemSensorManager$SensorEventQueue.dispatchSensorEvent(SystemSensorManager.java:862)
  at android.os.MessageQueue.nativePollOnce(Native method)
  at android.os.MessageQueue.next(MessageQueue.java:386)
  at android.os.Looper.loop(Looper.java:175)
  at android.app.ActivityThread.main(ActivityThread.java:7625)
  at java.lang.reflect.Method.invoke(Native method)
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:524)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:987)

这里的changeAudioType就是频繁的调用AudioManager来切换听筒和扬声器 首页说一下我们这边的功能，利用传感器的功能，当用户在视频通话的时候，可以进行听筒和扬声器自动切换 就是当用户把手机放在耳朵旁边的时候切换为听筒模式，离开的时候又切换为扬声器(微信也是有这个功能)

但是我们项目这个功能只是实现了一半，只要有东西挡住手机就会回调，所以如果用户平放，然后点击返回键的时候也是会触发这个回调，而且很奇怪就是报这个ANR问题的都是华为的手机

解决

加上旋转传感器来判断当前屏幕旋转的方向，来判断只有当手机拿起，而且是东西靠近手机的时候才设置为声筒模式，离开手机的时候就设置为扬声器模式

代码:

 private SensorEventListener sensorListener = new SensorEventListener() {
        @Override
        public void onSensorChanged(SensorEvent event) {

            //如果用户手机设置了听筒模式，或者用户当前没有在视频　就不执行
            if (ImSpUtils.isHeadphoneMode() || !MeetingStateUtils.isOnMeeting()) return;

            if (event.sensor.getType() == Sensor.TYPE_ROTATION_VECTOR){
                float x = Math.abs(event.values[0]);

                if (x >= Math.sin(Math.PI*minDegree/180)){
                    pickupPhone = true;
                }else {
                    pickupPhone = false;
                }
            }else if (event.sensor.getType() == Sensor.TYPE_PROXIMITY){

                float distance = event.values[0];
                float maxRange = event.sensor.getMaximumRange();
                float threshold = Math.min(maxRange, 3);

                if (mAudioManager.isSpeakerphoneOn()){
                    if (pickupPhone  && distance < threshold){
                        changeAudioType(true);
                    }
                }else{
                    if (distance >= threshold){
                        changeAudioType(false);
                    }
                }
            }
        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int accuracy) {
        }
    };

//注册两个传感器
mSensorManager.registerListener(sensorListener, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
mSensorManager.registerListener(sensorListener, mRotationSensor, SensorManager.SENSOR_DELAY_NORMAL);