1.底部导航栏实现

MyFragment.javapublic class MyFragment extends Fragment {
         private String content;    private TextView txt_title;    private FrameLayout myfragment_contet;    private Context mContext;    private ArrayList datas = null;    private FragmentManager fManager = null;    private long exitTime = 0;    public MyFragment(String content) {        this.content = content;    }    @Override    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {        if (content == "first1") {            View view = inflater.inflate(R.layout.myfg_message, container, false);            WebView main_webcontent = (WebView) view.findViewById(R.id.webView1);            String url = "http://www.baidu.com";            main_webcontent.loadUrl(url);            return view;        } else {            View view = inflater.inflate(R.layout.myfragment_content, container, false);            TextView txt_content = (TextView) view.findViewById(R.id.txt_content);            txt_content.setText(content);            return view;        }    }}

MainActivity.javapublic class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener{
         private RadioGroup rg_tab_bar;    private RadioButton rb_channel;    //Fragment Object    private MyFragment fg1,fg2,fg3,fg4;    private FragmentManager fManger;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        fManger =getFragmentManager();        rg_tab_bar = (RadioGroup) findViewById(R.id.rg_tab_bar);        rg_tab_bar.setOnCheckedChangeListener(this);        //获取第一个单选按钮，并设置其为选中状态        rb_channel = (RadioButton) findViewById(R.id.rb_channel);        rb_channel.setChecked(true);    }    @Override    public void onCheckedChanged(RadioGroup group, int checkedId) {        FragmentTransaction fTransaction = fManger.beginTransaction();        hideAllFragment(fTransaction);        switch (checkedId){            case R.id.rb_channel:                if(fg1 == null){                    fg1=new MyFragment("first1");                    fTransaction.add(R.id.ly_content,fg1);                }                else {                    fTransaction.show(fg1);                }                break;            case R.id.rb_message:                if(fg2 == null){                    fg2 = new MyFragment("第二个Fragment");                    fTransaction.add(R.id.ly_content,fg2);                }else{                    fTransaction.show(fg2);                }                break;            case R.id.rb_better:                if(fg3 == null){                    fg3 = new MyFragment("第三个Fragment");                    fTransaction.add(R.id.ly_content,fg3);                }else{                    fTransaction.show(fg3);                }                break;            case R.id.rb_setting:                if(fg4 == null){                    fg4 = new MyFragment("第四个Fragment");                    fTransaction.add(R.id.ly_content,fg4);                }else{                    fTransaction.show(fg4);                }                break;        }        fTransaction.commit();    }    //隐藏所有Fragment    private void hideAllFragment(FragmentTransaction fragmentTransaction){        if(fg1!=null)fragmentTransaction.hide(fg1);        if(fg2 != null)fragmentTransaction.hide(fg2);        if(fg3 != null)fragmentTransaction.hide(fg3);        if(fg4 != null)fragmentTransaction.hide(fg4);    }}

2.自动添加生命周期控件

You are correct: that code is automatically created for you by Android Studio, to aid in the implementation of the App Indexing API.

However, it is not created by simply adding a new activity to your app. You would need to explicitly ask Android Studio to create this code. You would then need to update it with details of your activity: Type of Action, Title, Deep Link, Corresponding Web Page (if one exists).

To have this code generated for you, you can use the pop-up intention list by Alt + Enter, select “Insert App Indexing API Code”:

enter image description here

Or you can use pop-up code generate list by Alt + Insert, select “App Indexing API Code”:

enter image description here