怎样给Android去除标题栏

1、在setContentView(R.layout.activity_main);之前添加getSupportActionBar().hide();只消除当前Activity的标题栏

2、在setContentView(R.layout.activity_main);之前添加requestWindowFeature(Window.FEATURE_NO_TITLE)；并将AppCompatActivity改为Activity，只消除当前Activity的标题栏

修改主题消除整个应用的所有标题栏我试了没好用，错误代码如下，还希望知道原因的小伙伴指教一下~

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.administrator.clouddiary/com.example.administrator.clouddiary.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.