android开发分享Android Jetpack 一个demo两分钟实现底部滑动导航栏

   BottomNavigationBar bottomNavigationBar;      FloatingActionButton fabHome;      Spinner modeSpinner;     Spinner shapeSpinner;     Spinner itemSpinner;     Spinner bgSpinner;     CheckBox autoHide;      Button toggleHide;     Button toggleBadge;      TextView message;     TextView scrollableText;      int lastSelectedPosition = 0;      TextFragment fragment1;     TextFragment fragment2;     TextFragment fragment3;     TextFragment fragment4;     TextFragment fragment5;     TextFragment fragment6;      @Nullable     TextBadgeItem numberBadgeItem;      @Nullable     ShapeBadgeItem shapeBadgeItem;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_home);          bottomNavigationBar = findViewById(R.id.bottom_navigation_bar);         fabHome = findViewById(R.id.fab_home);          modeSpinner = findViewById(R.id.mode_spinner);         bgSpinner = findViewById(R.id.bg_spinner);         shapeSpinner = findViewById(R.id.shape_spinner);         itemSpinner = findViewById(R.id.item_spinner);         autoHide = findViewById(R.id.auto_hide);          toggleHide = findViewById(R.id.toggle_hide);         toggleBadge = findViewById(R.id.toggle_badge);          message = findViewById(R.id.message);          fragment1 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para1));         fragment2 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para2));         fragment3 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para3));         fragment4 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para4));         fragment5 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para5));         fragment6 = TextFragmentKt.newTextFragmentInstance(getString(R.string.para6));          ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, new String[]{"MODE_DEFAULT", "MODE_FIXED", "MODE_SHIFTING", "MODE_FIXED_NO_TITLE", "MODE_SHIFTING_NO_TITLE"});         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);         modeSpinner.setAdapter(adapter);         modeSpinner.setSelection(2);          ArrayAdapter<String> itemAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, new String[]{"3 items", "4 items", "5 items"});         itemAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);         itemSpinner.setAdapter(itemAdapter);         itemSpinner.setSelection(2);          ArrayAdapter<String> shapeAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, new String[]{"SHAPE_OVAL", "SHAPE_RECTANGLE", "SHAPE_HEART", "SHAPE_STAR_3_VERTICES", "SHAPE_STAR_4_VERTICES", "SHAPE_STAR_5_VERTICES", "SHAPE_STAR_6_VERTICES"});         shapeAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);         shapeSpinner.setAdapter(shapeAdapter);         shapeSpinner.setSelection(5);          ArrayAdapter<String> bgAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, new String[]{"BACKGROUND_STYLE_DEFAULT", "BACKGROUND_STYLE_STATIC", "BACKGROUND_STYLE_RIPPLE"});         bgAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);         bgSpinner.setAdapter(bgAdapter);         bgSpinner.setSelection(1);          modeSpinner.setOnItemSelectedListener(this);         bgSpinner.setOnItemSelectedListener(this);         shapeSpinner.setOnItemSelectedListener(this);         itemSpinner.setOnItemSelectedListener(this);         autoHide.setOnCheckedChangeListener(this);          toggleHide.setOnClickListener(this);         toggleBadge.setOnClickListener(this);         fabHome.setOnClickListener(this);          bottomNavigationBar.setTabSelectedListener(this);     }      @Override     public boolean onCreateOptionsMenu(Menu menu) {         MenuInflater inflater = getMenuInflater();         inflater.inflate(R.menu.home_menu, menu);         return true;     }      @Override     public boolean onOptionsItemSelected(MenuItem item) {         switch (item.getItemId()) {             case R.id.menu_github:                 String url = "https://github.com/Ashok-Varma/BottomNavigation";                 Intent i = new Intent(Intent.ACTION_VIEW);                 i.setData(Uri.parse(url));                 startActivity(i);                 return true;         }         return super.onOptionsItemSelected(item);     }      @Override     public void onClick(View v) {         switch (v.getId()) {             case R.id.toggle_hide:                 if (bottomNavigationBar != null) {                     bottomNavigationBar.toggle();                 }                 break;             case R.id.toggle_badge:                 if (numberBadgeItem != null) {                     numberBadgeItem.toggle();                 }                 if (shapeBadgeItem != null) {                     shapeBadgeItem.toggle();                 }                 break;             case R.id.fab_home:                 final Snackbar snackbar = Snackbar.make(message, "Fab Clicked", Snackbar.LENGTH_LONG);                 snackbar.setAction("dismiss", new View.OnClickListener() {                     @Override                     public void onClick(View v) {                         snackbar.dismiss();                     }                 });                 snackbar.show();                 break;         }     }      @Override     public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {         refresh();     }      @Override     public void onNothingSelected(AdapterView<?> adapterView) {      }      @Override     public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {         refresh();     }      private void refresh() {          bottomNavigationBar.clearAll(); //        bottomNavigationBar.setFab(fabHome, BottomNavigationBar.FAB_BEHAVIOUR_TRANSLATE_AND_STICK);         bottomNavigationBar.setFab(fabHome);          setScrollableText(lastSelectedPosition);          numberBadgeItem = new TextBadgeItem()                 .setBorderWidth(4)                 .setBackgroundColorResource(R.color.blue)                 .setText("" + lastSelectedPosition)                 .setHideOnSelect(autoHide.isChecked());          shapeBadgeItem = new ShapeBadgeItem()                 .setShape(shapeSpinner.getSelectedItemPosition())                 .setShapeColorResource(R.color.teal)                 .setGravity(Gravity.TOP | Gravity.END)                 .setHideOnSelect(autoHide.isChecked());          bottomNavigationBar.setMode(modeSpinner.getSelectedItemPosition());         bottomNavigationBar.setBackgroundStyle(bgSpinner.getSelectedItemPosition());           switch (itemSpinner.getSelectedItemPosition()) {             case 0:                 bottomNavigationBar                         .addItem(new BottomNavigationItem(R.drawable.ic_location_on_white_24dp, "Nearby").setActiveColorResource(R.color.orange).setBadgeItem(numberBadgeItem))                         .addItem(new BottomNavigationItem(R.drawable.ic_find_replace_white_24dp, "Find").setActiveColorResource(R.color.teal))                         .addItem(new BottomNavigationItem(R.drawable.ic_favorite_white_24dp, "Categories").setActiveColorResource(R.color.blue).setBadgeItem(shapeBadgeItem))                         .setFirstSelectedPosition(lastSelectedPosition > 2 ? 2 : lastSelectedPosition)                         .initialise();                 break;             case 1:                 bottomNavigationBar                         .addItem(new BottomNavigationItem(R.drawable.ic_home_white_24dp, "Home").setActiveColorResource(R.color.orange).setBadgeItem(numberBadgeItem))                         .addItem(new BottomNavigationItem(R.drawable.ic_book_white_24dp, "Books").setActiveColorResource(R.color.teal))                         .addItem(new BottomNavigationItem(R.drawable.ic_music_note_white_24dp, "Music").setActiveColorResource(R.color.blue).setBadgeItem(shapeBadgeItem))                         .addItem(new BottomNavigationItem(R.drawable.ic_tv_white_24dp, "Movies & TV").setActiveColorResource(R.color.brown))                         .setFirstSelectedPosition(lastSelectedPosition > 3 ? 3 : lastSelectedPosition)                         .initialise();                 break;             case 2:                 bottomNavigationBar                         .addItem(new BottomNavigationItem(R.drawable.ic_home_white_24dp, "Home").setActiveColorResource(R.color.orange).setBadgeItem(numberBadgeItem))                         .addItem(new BottomNavigationItem(R.drawable.ic_book_white_24dp, "Books").setActiveColorResource(R.color.teal))                         .addItem(new BottomNavigationItem(R.drawable.ic_music_note_white_24dp, "Music").setActiveColorResource(R.color.blue).setBadgeItem(shapeBadgeItem))                         .addItem(new BottomNavigationItem(R.drawable.ic_tv_white_24dp, "Movies & TV").setActiveColorResource(R.color.brown))                         .addItem(new BottomNavigationItem(R.drawable.ic_videogame_asset_white_24dp, "Games").setActiveColorResource(R.color.grey))                         .setFirstSelectedPosition(lastSelectedPosition)                         .initialise();                 break;         }     }      @Override     public void onTabSelected(int position) {         lastSelectedPosition = position;         setMessageText(position + " Tab Selected");         if (numberBadgeItem != null) {             numberBadgeItem.setText(Integer.toString(position));         }         setScrollableText(position);     }      @Override     public void onTabUnselected(int position) {     }      @Override     public void onTabReselected(int position) {         setMessageText(position + " Tab Reselected");     }      private void setMessageText(String messageText) {         message.setText(messageText);     }      private void setScrollableText(int position) {         switch (position) {             case 0:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment1).commitAllowingStateLoss();                 break;             case 1:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment2).commitAllowingStateLoss();                 break;             case 2:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment3).commitAllowingStateLoss();                 break;             case 3:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment4).commitAllowingStateLoss();                 break;             case 4:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment5).commitAllowingStateLoss();                 break;             default:                 getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_frag_container, fragment6).commitAllowingStateLoss();                 break;         }     } }