<Button
android:id="@+id/btnok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
tools:layout_editor_absoluteX="158dp"
tools:layout_editor_absoluteY="463dp" />
//-----------------------------------------------------------------------------------------------------
public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 找到按钮
Button myButton = findViewById(R.id.btnok);

// 为按钮设置单击事件监听器
myButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
       
        // 在这里编写按钮单击时的代码
        Toast.makeText(MainActivity.this, "Button Clicked!", Toast.LENGTH_SHORT).show();
    }
});

}
}