我的随机数生成器总是返回零

导入androidx.appcompat.app.AppCompatActivity;

导入android.os.Bundle;

导入android.util.Log;

导入android.view.View;

导入android.widget.EditText;

导入android.widget.Toast;

导入java.util.Random;

公共类MainActivity扩展了AppCompatActivity {

int random;

public void createRandomNum() {     // Function than creating random number

    Random rand = new Random();

    int random = rand.nextInt(21);

}

public void guess(View view) {

    EditText guess = (EditText) findViewById(R.id.editText);
    int guessInt = Integer.parseInt(guess.getText().toString());
    String message;
    if (guessInt == random) {

        message = "congo!!";

    }
    else if (guessInt > random) {

        message = "Lower!!";

    }
    else {

        message = "Higher!!";

    }

    Toast.makeText(this, message, Toast.LENGTH_SHORT).show();

    createRandomNum();       //calling createRandomNum() function

}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    createRandomNum();   //calling that function
}

}

//在android模拟器中运行它之后，它总是猜测值为零