Android适配底部虚拟按键的方法详解

public class TestActivity extends AppCompatActivity {

 private View decorView;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_test);
  //获取顶层视图
  decorView = getWindow().getDecorView();
 }

 @Override
 protected void onStart() {
  //调用配置
  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;
  //判断当前版本在4.0以上并且存在虚拟按键，否则不做操作
  if (Build.VERSION.SDK_INT < 19 || !checkDeviceHasNavigationBar()) {
  //一定要判断是否存在按键，否则在没有按键的手机调用会影响别的功能。如之前没有考虑到，导致图传全屏变成小屏显示。
   return;
  } else {
   // 获取属性
   decorView.setSystemUiVisibility(flag);
  }
 }

 /**
  * 判断是否存在虚拟按键
  * @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;
 }