Gallery g = (Gallery)findViewById(R.id.secondButton);  因为这句运行报错，放鼠标在这上面时显示

@Deprecated

This class was deprecated in API level 16.
This widget is no longer supported. Other horizontally scrolling widgets include HorizontalScrollView and ViewPager from the support library.

删除Gallery g = (Gallery)findViewById(R.id.secondButton);就可以了   

用这种表示   secondButton = (Button)findViewById(R.id.secondButton);

求大神求解

android.widget.Button cannot be cast to android.widget.Gallery,布布扣,bubuko.com

android.widget.Button cannot be cast to android.widget.Gallery