1. getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

2.
 onResume  中啟用
  wakeLock = ((PowerManager) getSystemService(POWER_SERVICE))
    .newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK
      | PowerManager.ON_AFTER_RELEASE, TAG);
  wakeLock.acquire();

onPause 中禁用
  if (wakeLock != null) {
   wakeLock.release();
  }

  mContentResolver = getContentResolver();
  setLockPatternEnabled(false);
 public void setLockPatternEnabled(boolean enabled) {
  setBoolean(android.provider.Settings.System.LOCK_PATTERN_ENABLED,
    enabled);
 }
 private void setBoolean(String systemSettingKey, boolean enabled) {
  android.provider.Settings.System.putInt(mContentResolver,
    systemSettingKey, enabled ? 1 : 0);
 }

權限  <uses-permission android:name="android.permission.WRITE_SETTINGS" />