Android通过应用来设置系统时间

public class SystemDateTime {
static final String TAG = "SystemDateTime";

public static void setDateTime(int year, int month, int day, int hour, int minute) throws IOException, InterruptedException {

requestPermission();

Calendar c = Calendar.getInstance();

c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month - 1);
c.set(Calendar.DAY_OF_MONTH, day);
c.set(Calendar.HOUR_OF_DAY, hour);
c.set(Calendar.MINUTE, minute);

long when = c.getTimeInMillis();

if (when / 1000 < Integer.MAX_VALUE) {
SystemClock.setCurrentTimeMillis(when);
}

long now = Calendar.getInstance().getTimeInMillis();
//Log.d(TAG, "set tm="+when + ", now tm="+now);

if (now - when > 1000)
throw new IOException("failed to set Date.");

}

public static void setDate(int year, int month, int day) throws IOException, InterruptedException {

requestPermission();

Calendar c = Calendar.getInstance();

c.set(Calendar.YEAR, year);
c.set(Calendar.MONTH, month);
c.set(Calendar.DAY_OF_MONTH, day);
long when = c.getTimeInMillis();

if (when / 1000 < Integer.MAX_VALUE) {
SystemClock.setCurrentTimeMillis(when);
}

long now = Calendar.getInstance().getTimeInMillis();
//Log.d(TAG, "set tm="+when + ", now tm="+now);

if (now - when > 1000)
throw new IOException("failed to set Date.");
}

public static void setTime(int hour, int minute) throws IOException, InterruptedException {

requestPermission();

Calendar c = Calendar.getInstance();

c.set(Calendar.HOUR_OF_DAY, hour);
c.set(Calendar.MINUTE, minute);
long when = c.getTimeInMillis();

if (when / 1000 < Integer.MAX_VALUE) {
SystemClock.setCurrentTimeMillis(when);
}

long now = Calendar.getInstance().getTimeInMillis();
//Log.d(TAG, "set tm="+when + ", now tm="+now);

if (now - when > 1000)
throw new IOException("failed to set Time.");
}

static void requestPermission() throws InterruptedException, IOException {
createSuProcess("chmod 666 /dev/alarm").waitFor();
}

static Process createSuProcess() throws IOException {
File rootUser = new File("/system/xbin/ru");
if (rootUser.exists()) {
return Runtime.getRuntime().exec(rootUser.getAbsolutePath());
} else {
return Runtime.getRuntime().exec("su");
}
}

static Process createSuProcess(String cmd) throws IOException {

DataOutputStream os = null;
Process process = createSuProcess();

try {
os = new DataOutputStream(process.getOutputStream());
os.writeBytes(cmd + "\n");
os.writeBytes("exit $?\n");
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
}
}
}

return process;
}
}