Question

我正在使用Android Studio制作App。

我有一个

public class MainActivity extends Activity implements View.OnClickListener, OnCheckedChangeListener

我需要在MainActivity中添加“ AppCompatActivity”。

我在Internet上进行了搜索，发现只有一个可以用于扩展。

所以我改为

public class MainActivity extends Activity implements View.OnClickListener, OnCheckedChangeListener, AppCompatActivity

这和AppCompatActivity出现错误“此处需要接口”。

我该如何解决这个问题？

Answer 1

AppCompatActivity是一个类，不是接口，因此您不能使用implements关键字来继承AppCompatActivity

您需要使用extends关键字来继承AppCompatActivity类

使用此

public class MainActivity extends AppCompatActivity implements View.OnClickListener, OnCheckedChangeListener

代替

public class MainActivity extends Activity implements View.OnClickListener, OnCheckedChangeListener, AppCompatActivity

Answer 2

The 'Interface expected here' occurs when you implement a class, not an interface. AppCompatActivity is a class which you are not able to implement.

I don't know why you want to extend from Activity in addition toAppCompatActivity, AppCompatActivity inherits from Activity already.

AppCompatActivity > FragmentActivity > SupportActivity > Activity

Just write:

public class MainActivity extends AppCompatActivity implements View.OnClickListener, OnCheckedChangeListener {

There is no need to extend Activity for you when you do it like that.

如何使用多种工具？

2 个答案: