Android Log.isLoggable 妙用

近來發現源碼裏面好多地方用到了 Log.isLoggable , 一查一看，是個東西，適合系統層以及root 主板設備上使用，能實現動態開關

android.util.Log.isLoggable(TAG, android.util.Log.DEBUG)

如上面代碼以及文檔說明，setprop log.tag.YOUR_LOG_TAG LEVEL 開啓指定級別的日誌開關屬性，VERBOSE, DEBUG, INFO, WARN, ERROR, ASSERT, or SUPPRESS. SUPPRESS will turn off all logging for your tag. 一目瞭然了啊，

adb shell setprop log.tag.VxApk D
adb shell setprop log.tag.SUPPRESS

另外還有收穫的是，系統重啓之後prop 會被還原，所以瞭解到了重啓系統服務這招，ServiceManager/ SystemServer/

adb shell stop
adb shell start

public static boolean restartSystemServer() {
        try {
            OutputStream out;
            Process process = createSuProcess();
            String cmd = "stop \n";
            out = process.getOutputStream();
            out.write(cmd.getBytes());
            cmd = "start \n";
            out.write(cmd.getBytes());
            out.flush();
            out.close();
            return true;
        } catch (IOException e) {
            Log.error(TAG, "restartSystemServer error");
        }
        return false;
 }