AndroidStudio按钮点击事件和时间显示

1.日期工具类
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateUtil {

    public static String getDateTime(){
        SimpleDateFormat ss =new SimpleDateFormat("HH:mm:ss");
        return ss.format(new Date());
    }
}

2.按钮点击监听

private Button btn;
private TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = findViewById(R.id.text);
    btn = findViewById(R.id.btn);
    btn.setOnClickListener(new MyOnClickListener(textView));

}

static class MyOnClickListener implements View.OnClickListener {

    private final TextView textView;

    public MyOnClickListener(TextView textView) {
        this.textView = textView;
    }

    public void onClick(View v) {
       String ss=String.format("点击：%s", DateUtil.getDateTime());
         textView.setText(ss);
    }

}