问具有更改活动的布局上的动画

EN

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signup);
        mSignUpButton = findViewById(R.id.btnSigUp);
        linearLayout=findViewById(R.id.linearLayout1);
        mGotoLoginActivityButton=findViewById(R.id.btnLoginSignUpActivity);
        slideDown= AnimationUtils.loadAnimation(getApplicationContext(),R.anim.slide_down);

      
//listener for Login button
        mGotoLoginActivityButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                //setValidation();

                Intent intent = new Intent(SignupActivity.this, LoginActivity.class);
                startActivity(intent);
                linearLayout.startAnimation(slideDown);

            }
        });
    }