三、开发遇到的问题汇总
1、如果发现wifi当前是开着的，而却发现关机再重启却没自动开启的话，很有可能是飞行模式揉的货！修改数据库即可正常，如下：
sqlite3 /data/data/com.Android.providers.settings/databases/settings.db
delete from system where name = 'airplane_mode_on';
.exit
2、wi-fi信号强度问题
源码位置2.2和2.3不同，2.2在frameworks/base/services/java/com/android/server/status/StatusBarPolicy.java
2.3在frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/StatusBarPolicy.java
2.3中单独成为一个apk，叫SystemUI.apk, 从源码位置也能看出来。更新wifi status bar部分代码如下：
else if (action.equals(WifiManager.NETWORK_STATE_CHANGED_ACTION) ||
action.equals(WifiManager.WIFI_STATE_CHANGED_ACTION) ||
action.equals(WifiManager.RSSI_CHANGED_ACTION)) {
updateWifi(intent); }
private final void updateWifi(Intent intent) {
final String action = intent.getAction();
if (action.equals(WifiManager.WIFI_STATE_CHANGED_ACTION)) {
final boolean enabled = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,
WifiManager.WIFI_STATE_UNKNOWN) == WifiManager.WIFI_STATE_ENABLED;
if (!enabled) {
// If disabled, hide the icon. (We show icon when connected.)
mService.setIconVisibility("wifi", false);
}
} else if (action.equals(WifiManager.SUPPLICANT_CONNECTION_CHANGE_ACTION)) {
final boolean enabled = intent.getBooleanExtra(WifiManager.EXTRA_SUPPLICANT_CONNECTED,
false);
if (!enabled) {
mService.setIconVisibility("wifi", false);
}
} else if (action.equals(WifiManager.RSSI_CHANGED_ACTION)) {
int iconId;
final int newRssi = intent.getIntExtra(WifiManager.EXTRA_NEW_RSSI, -200);
int newSignalLevel = WifiManager.calculateSignalLevel(newRssi,
sWifiSignalImages[0].length);
if (newSignalLevel != mLastWifiSignalLevel) {
mLastWifiSignalLevel = newSignalLevel;
if (mIsWifiConnected) {
iconId = sWifiSignalImages[mInetCondition][newSignalLevel];
} else {
iconId = sWifiTemporarilyNotConnectedImage;
}
mService.setIcon("wifi", iconId, 0);
}
}
}
/**
* Calculates the level of the signal. This should be used any time a signal
* is being shown.
*
* @param rssi The power of the signal measured in RSSI.
* @param numLevels The number of levels to consider in the calculated
* level.
* @return A level of the signal, given in the range of 0 to numLevels-1
* (both inclusive).
*/
public static int calculateSignalLevel(int rssi, int numLevels) {
if (rssi <= MIN_RSSI) {
return 0;
} else if (rssi >= MAX_RSSI) {
return numLevels - 1;
} else {
int partitionSize = (MAX_RSSI - MIN_RSSI) / (numLevels - 1);
return (rssi - MIN_RSSI) / partitionSize;
}
}
I/WifiStateTracker( 1799): ----------getRssiApprox------------WifiNative.getRssiCommand():-20
I/WifiStateTracker( 1799): ---------------------->newRssi:-20
I/WifiStateTracker( 1799): ---------------------->newSignalLevel:3
根据log可发现level为-20，而根据计算公式算为 （-55 - （-100））/ 3 = 15；
若rssi level = -20，那么结果为 （-20 - （-100））/ 15 = 5。
后来发现自己忽略了前面一个if语句，-20 明显 > -55，将不进入计算分支，而直接计算 4 - 1 = 3；
所以问题就解决了！