java - WifiManager.setWifiEnabled() 究竟返回什么？

Question

你们中有人有过 setWifiEnabled() 返回值的经验吗？

文档不清楚，它说:

Returns true if the operation succeeds (or if the existing state is the same as the requested state).

运行失败怎么办？它会抛出异常还是返回 false？

是否可以这样做:

if (!WifiManager.setWifiEnabled(true)) {
    Log.i(LOG_TAG, "Wifi switch failed.");
} else {
    Log.i(LOG_TAG, "Wifi switch succeeded.")
}

非常感谢。

Answer 1

已接受的答案已过时(来源来自 android 4.2，其中当前的 android 现在是 10，11 将很快推出)。此方法可以返回 false。 WifiServiceImpl.java是处理WifiManager#setWifiEnabled(boolean)的电流源:

代码:

 /**
 * see {@link android.net.wifi.WifiManager#setWifiEnabled(boolean)}
 * @param enable {@code true} to enable, {@code false} to disable.
 * @return {@code true} if the enable/disable operation was
 *         started or is already in the queue.
 */
@Override
public synchronized boolean setWifiEnabled(String packageName, boolean enable) {
    if (enforceChangePermission(packageName) != MODE_ALLOWED) {
        return false;
    }
    boolean isPrivileged = isPrivileged(Binder.getCallingPid(), Binder.getCallingUid());
    if (!isPrivileged && !isDeviceOrProfileOwner(Binder.getCallingUid())
            && !mWifiPermissionsUtil.isTargetSdkLessThan(packageName, Build.VERSION_CODES.Q,
              Binder.getCallingUid())
            && !isSystem(packageName, Binder.getCallingUid())) {
        mLog.info("setWifiEnabled not allowed for uid=%")
                .c(Binder.getCallingUid()).flush();
        return false;
    }
    // If Airplane mode is enabled, only privileged apps are allowed to toggle Wifi
    if (mSettingsStore.isAirplaneModeOn() && !isPrivileged) {
        mLog.err("setWifiEnabled in Airplane mode: only Settings can toggle wifi").flush();
        return false;
    }
    // If SoftAp is enabled, only privileged apps are allowed to toggle wifi
    boolean apEnabled = mWifiApState == WifiManager.WIFI_AP_STATE_ENABLED;
    if (apEnabled && !isPrivileged) {
        mLog.err("setWifiEnabled SoftAp enabled: only Settings can toggle wifi").flush();
        return false;
    }
    // If we're in crypt debounce, ignore any wifi state change APIs.
    if (mFrameworkFacade.inStorageManagerCryptKeeperBounce()) {
        return false;
    }
    mLog.info("setWifiEnabled package=% uid=% enable=%").c(packageName)
            .c(Binder.getCallingUid()).c(enable).flush();
    long ident = Binder.clearCallingIdentity();
    try {
        if (!mSettingsStore.handleWifiToggled(enable)) {
            // Nothing to do if wifi cannot be toggled
            return true;
        }
    } finally {
        Binder.restoreCallingIdentity(ident);
    }
    mWifiMetrics.incrementNumWifiToggles(isPrivileged, enable);
    mWifiController.sendMessage(CMD_WIFI_TOGGLED);
    return true;
}