public void registerReceiver() { Log.e(TAG, "SDMC isRegister " + isRegister); if (!isRegister) { isRegister = true; IntentFilter filter = new IntentFilter(); filter.addAction(ACTION_FACTORY_RESET); filter.addAction(ACTION_SCREEN_OFF); filter.addAction(ACTION_SCREEN_ON); filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS); registerReceiver(receiver, filter); }

这段代码是在Android应用程序中注册一个BroadcastReceiver，用于接收系统发送的多个广播。通过IntentFilter对象，将该BroadcastReceiver注册为接收多个广播的监听器。其中，ACTION_FACTORY_RESET、ACTION_SCREEN_OFF、ACTION_SCREEN_ON、Intent.ACTION_CLOSE_SYSTEM_DIALOGS都是系统级别的广播，用于接收设备恢复出厂设置、锁屏、解锁和关闭系统对话框的广播。当系统发送这些广播时，被注册的BroadcastReceiver就会收到该广播并执行相应的操作。通过isRegister变量的判断，可以避免重复注册BroadcastReceiver。

相关问题

public void register() { if (isRegister.get()) { LogUtils.e(TAG, "apmReceiver already register..."); return; } LogUtils.i(TAG,"apmReceiver register...." ); isRegister.set(true); IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(Intent.ACTION_BATTERY_CHANGED); intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE"); context.registerReceiver(apmReceiver, intentFilter); networkType = JJDataUtils.getNetworkType(context); jjApmSDKImpl = JJApmSDKImpl.getApmIpmAfterInit(); }

这段代码主要是注册一个 BroadcastReceiver 监听电量变化和网络状态变化，并且在注册之前进行了判断，避免重复注册。优化建议如下：

1. 可以将 isRegister 的判断放到 context.registerReceiver 方法的内部，这样可以避免在多线程环境下出现并发问题。

2. 可以将 intentFilter 的初始化和 addAction 方法的调用合并到一起，这样可以减少代码量。

3. 可以将 BroadcastReceiver 的实例化放到方法内部，并且使用匿名内部类来实现，可以避免在类中定义过多的实例变量。

4. 在注册 BroadcastReceiver 之前，可以先判断 context 是否为 null，以避免出现空指针异常。

下面是优化后的代码：

public void register() {
if (isRegister.get()) {
LogUtils.e(TAG, "apmReceiver already register...");
return;
}
isRegister.set(true);
if (context == null) {
LogUtils.e(TAG, "context is null, cannot register apmReceiver!");
return;
}
LogUtils.i(TAG, "apmReceiver register....");
IntentFilter intentFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
context.registerReceiver(new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())) {
// 处理电量变化
} else if ("android.net.conn.CONNECTIVITY_CHANGE".equals(intent.getAction())) {
// 处理网络状态变化
}
}
}, intentFilter);
networkType = JJDataUtils.getNetworkType(context);
jjApmSDKImpl = JJApmSDKImpl.getApmIpmAfterInit();
}

private void updateShowSeconds() { if (mShowSeconds) { // Wait until we have a display to start trying to show seconds. if (mSecondsHandler == null && getDisplay() != null) { mSecondsHandler = new Handler(); if (getDisplay().getState() == Display.STATE_ON) { mSecondsHandler.postAtTime(mSecondTick, SystemClock.uptimeMillis() / 1000 * 1000 + 1000); } IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF); filter.addAction(Intent.ACTION_SCREEN_ON); mContext.registerReceiver(mScreenReceiver, filter); } } else { if (mSecondsHandler != null) { mContext.unregisterReceiver(mScreenReceiver); mSecondsHandler.removeCallbacks(mSecondTick); mSecondsHandler = null; updateClock(); } } } private final BroadcastReceiver mScreenReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (Intent.ACTION_SCREEN_OFF.equals(action)) { if (mSecondsHandler != null) { mSecondsHandler.removeCallbacks(mSecondTick); } } else if (Intent.ACTION_SCREEN_ON.equals(action)) { if (mSecondsHandler != null) { mSecondsHandler.postAtTime(mSecondTick, SystemClock.uptimeMillis() / 1000 * 1000 + 1000); } } } }; private final Runnable mSecondTick = new Runnable() { @Override public void run() { if (mCalendar != null) { updateClock(); } mSecondsHandler.postAtTime(this, SystemClock.uptimeMillis() / 1000 * 1000 + 1000); } }; } Android4.4编译报错getDisplay().getState(

根据您提供的代码，可能是因为在Android4.4中没有`getDisplay().getState()`这个方法而导致编译报错。可以尝试使用`getSystemService(Context.WINDOW_SERVICE).getDefaultDisplay().getState()`来获取屏幕状态。请修改代码如下：

private void updateShowSeconds() {
    if (mShowSeconds) {
        // Wait until we have a display to start trying to show seconds.
        if (mSecondsHandler == null && getSystemService(Context.WINDOW_SERVICE).getDefaultDisplay() != null) {
            mSecondsHandler = new Handler();
            if (getSystemService(Context.WINDOW_SERVICE).getDefaultDisplay().getState() == Display.STATE_ON) {
                mSecondsHandler.postAtTime(mSecondTick, SystemClock.uptimeMillis() / 1000 * 1000 + 1000);
            }
            IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
            filter.addAction(Intent.ACTION_SCREEN_ON);
            mContext.registerReceiver(mScreenReceiver, filter);
        }
    } else {
        if (mSecondsHandler != null) {
            mContext.unregisterReceiver(mScreenReceiver);
            mSecondsHandler.removeCallbacks(mSecondTick);
            mSecondsHandler = null;
            updateClock();
        }
    }
}

private final BroadcastReceiver mScreenReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (Intent.ACTION_SCREEN_OFF.equals(action)) {
            if (mSecondsHandler != null) {
                mSecondsHandler.removeCallbacks(mSecondTick);
            }
        } else if (Intent.ACTION_SCREEN_ON.equals(action)) {
            if (mSecondsHandler != null) {
                mSecondsHandler.postAtTime(mSecondTick, SystemClock.uptimeMillis() / 1000 * 1000 + 1000);
            }
        }
    }
};

private final Runnable mSecondTick = new Runnable() {
    @Override
    public void run() {
        if (mCalendar != null) {
            updateClock();
        }
        mSecondsHandler.postAtTime(this, SystemClock.uptimeMillis() / 1000 * 1000 + 1000);
    }
};