public class TestActivity extends AppCompatActivity { private View decorView; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_test);  //獲取頂層視圖  decorView = getWindow().getDecorView(); } @Override protected void onStart() {  //調用配置  init();  super.onStart(); } private void init(){  int flag = View.SYSTEM_UI_FLAG_LAYOUT_STABLE    | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN    | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide    | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar    | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY;  //判斷當前版本在4.0以上并且存在虛擬按鍵，否則不做操作  if (Build.VERSION.SDK_INT < 19 || !checkDeviceHasNavigationBar()) {  //一定要判斷是否存在按鍵，否則在沒有按鍵的手機調用會影響別的功能。如之前沒有考慮到，導致圖傳全屏變成小屏顯示。   return;  } else {   // 獲取屬性   decorView.setSystemUiVisibility(flag);  } } /**  * 判斷是否存在虛擬按鍵  * @return  */ public boolean checkDeviceHasNavigationBar() {  boolean hasNavigationBar = false;  Resources rs = getResources();  int id = rs.getIdentifier("config_showNavigationBar", "bool", "android");  if (id > 0) {   hasNavigationBar = rs.getBoolean(id);  }  try {   Class<?> systemPropertiesClass = Class.forName("android.os.SystemProperties");   Method m = systemPropertiesClass.getMethod("get", String.class);   String navBarOverride = (String) m.invoke(systemPropertiesClass, "qemu.hw.mainkeys");   if ("1".equals(navBarOverride)) {    hasNavigationBar = false;   } else if ("0".equals(navBarOverride)) {    hasNavigationBar = true;   }  } catch (Exception e) {  }  return hasNavigationBar; } @Override public boolean onTouch(View v, MotionEvent event) {  return false; }