public class MainActivity extends AppCompatActivity {
Fragment fragment = null;
protected void onCreate(Bundle savedInstanceState) { setContentView(R.layout.activity_main
警告:存储库'oss_update‘似乎过时了。考虑使用不同的镜像或server.读取已安装的软件包..。没什么可做的。[done]
Repository 'oss' is up to date.Retrieving repository 'oss_update' metadata .........................................................| oss