我正在尝试在创建的活动上设置默认项目,但它不起作用? 这是我的代码:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_userhome);
mTextMessage = (TextView) findViewById(R.id.message);
profile = (FrameLayout) findViewById(R.id.profile);
mall = (FrameLayout) findViewById(R.id.mall);
dietplan =(FrameLayout) findViewById(R.id.dietplan);
BottomNavigationView navigation = (BottomNavigationView)
findViewById(R.id.navigation);
navigation.setSelectedItemId(R.id.dietplan);
navigation.setOnNavigationItemSelectedListener
(mOnNavigationItemSelectedListener);
}
但似乎navigation.setSelectedItemId(R.id.dietplan);
无效。请帮我设置底部导航栏的默认项目:
这是我的堆栈跟踪(logcat):
FATAL EXCEPTION: main
Process: gym.android.ommsoftware.gym, PID: 1915
java.lang.RuntimeException: Unable to start activity ComponentInfo{gym.android.ommsoftware.gym/gym.android.ommsoftware.gym.Userhome}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2404)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at gym.android.ommsoftware.gym.Userhome.onCreate(Userhome.java:57)
at android.app.Activity.performCreate(Activity.java:5541)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分:23)
您需要setChecked(true)
该项目,而非选择。试试这段代码
mBottomNavigationView=(BottomNavigationView)findViewById(R.id.bottom_nav);
mBottomNavigationView.getMenu().findItem(R.id.item_id).setChecked(true);
选中的项目在BottomNavigationView
中突出显示。
答案 1 :(得分:9)
只需分享我的工作源代码
在Xml中,
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.BottomNavigationView
android:background="@color/colorWhite"
android:id="@+id/gfPrlBnvBtmView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="start"
android:layout_alignParentBottom="true"
app:menu="@menu/bottom_navigation_main" />
</LinearLayout>
在Java中,
public class TestActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener
{
private BottomNavigationView mBtmView;
private int mMenuId;
@Override
public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {
super.onCreate(savedInstanceState, persistentState);
setContentView(R.layout.test);
mBtmView = (BottomNavigationView) findViewById(R.id.gfPrlBnvBtmView);
mBtmView.setOnNavigationItemSelectedListener(this);
mBtmView.getMenu().findItem(R.id.action_yoga).setChecked(true);
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
// uncheck the other items.
mMenuId = item.getItemId();
for (int i = 0; i < mBtmView.getMenu().size(); i++) {
MenuItem menuItem = mBtmView.getMenu().getItem(i);
boolean isChecked = menuItem.getItemId() == item.getItemId();
menuItem.setChecked(isChecked);
}
switch (item.getItemId()) {
case R.id.action_food: {
}
break;
case R.id.action_medical: {
}
break;
case R.id.action_yoga: {
}
break;
case R.id.action_postures: {
}
break;
}
return true;
}
}
答案 2 :(得分:6)
在片段中
getActivity()?.myNavigationViewId?.selectedItemId = R.id.other_tab_id
在活动中
myNavigationViewId?.selectedItemId = R.id.other_tab_id
注意:请确保将
myNavigationViewId
和other_tab_id
替换为实际的导航视图和标签ID。
答案 3 :(得分:2)
Kotlin片段溶液
var fragment = Fragment()
bottomNav = findViewById(R.id.bottom_nav)
bottomNav.setOnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.home -> {
fragment = HomeForm()
}
R.id.score -> {
fragment = ScoreForm()
}
}
supportFragmentManager
.beginTransaction()
.replace(R.id.frame_layout, fragment)
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
.commit()
true
}
bottomNav.selectedItemId = R.id.score // init open score tab
答案 4 :(得分:1)
这对我有用
活动布局:
<android.support.design.widget.BottomNavigationView
android:id="@+id/bottomNavigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:itemBackground="@color/colorPrimary"
app:itemIconTint="@color/tabs"
app:itemTextColor="@color/tabs"
app:menu="@menu/bottom_navigation_main" />
<强>颜色/ tabs.xml:强>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:color="@color/not_active" android:state_checked="false"/>
<item android:color="@color/active" android:state_checked="true"/>
</selector>
点击回调:
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.action_tab0:
setFragment(f0);
break;
case R.id.action_tab1:
setFragment(f1);
break;
}
return true; // not false!
}
答案 5 :(得分:1)
您还可以使用以下索引在BottomNavigatioView中设置选择:
public void selectBottomNavigationOption(int index) {
switch (index) {
case 0:
index = R.id.action_1;
break;
case 1:
index = R.id.action_2;
break;
case 2:
index = R.id.action_3;
break;
case 3:
index = R.id.action_4;
break;
}
bottomNavigationView.setSelectedItemId(index);
}
答案 6 :(得分:1)
将 android:enabled="true"
添加到您的BottomNavigation菜单项。
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="@+id/menu_id"
android:enabled="true"
android:icon="@drawable/ic_my_icon"
android:title="@string/menu_title"/>
</menu>
在onCreate()
方法中,
通过设置听众
bottomNavigationView.setOnNavigationItemSelectedListener(mListener)
。
并通过执行bottomNavigationView.selectedItemId = R.id.menu_id
设置要选择的所需项目。
无论何时创建活动,这都会从onNavigationItemSelected()
触发NavigationItemSelectedListener
。
答案 7 :(得分:1)
您可以使用:
navigationView?.menu?.findItem(drawableMenuItem.id)?.isChecked = true
,它将不会触发OnNavigationItemSelectedListener
个事件。
答案 8 :(得分:0)
Kotlin扩展版Abshishek's回答:
internal fun BottomNavigationView.checkItem(actionId: Int) {
menu.findItem(actionId)?.isChecked = true
}
// use
bottom_navigation.checkItem(R.id.navigation_home)
这不会触发OnNavigationItemSelectedListener
。
答案 9 :(得分:0)
如果您想要的是在视图上忽略clicked元素,并且不将其作为“ selected”返回,则可以在处理了click之后返回false,在某些情况下和某些设计中,您可能需要打开活动而不是一个片段,活动结束后,这将使所选内容成为底部的项目。
private val onNavigationItemSelectedListener = BottomNavigationView.OnNavigationItemSelectedListener { item ->
when (item.itemId) {
R.id.navigation_shipment -> {
currentItem = TAB_INDEX_SHIPMENT
val intent = Intent(this, BookShipmentActivity::class.java)
startActivity(intent)
return@OnNavigationItemSelectedListener false
}
}
false
}
答案 10 :(得分:0)
仅供参考:对于片段,onCreateView
BottomNavigationView mBottomNavigationView = getActivity().findViewById(R.id.bottomNavigationView);
mBottomNavigationView.setSelectedItemId(R.id.your_item);
答案 11 :(得分:0)
有两个senario
设置所选菜单项的ID。行为与点击项目相同。
代码示例:
BottomNavigationView bottomNavigationView;
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottomNavigationView);
bottomNavigationView.setOnNavigationItemSelectedListener(myNavigationItemListener);
bottomNavigationView.setSelectedItemId(R.id.my_menu_item_id);
我只需要检查它而无需点击
代码示例:
BottomNavigationView bottomNavigationView= (getActivity()).findViewById(R.id.bottom_navigation);
bottomNavigationView.getMenu().findItem(R.id.action_manage_orders_id).setChecked(true);
答案 12 :(得分:0)
对我来说,setSelectedItemId(int id)
只显示了片段,但选择的菜单项仍然是错误的。
我发现在 setSelectedItemId(int id)
全部设置后调用 BottomNavigationView
是不够的。
我不再在 setSelectedItemId(int id)
中调用 onCreate(savedInstanceState: Bundle?)
,而是开始在 onResume()
中调用它。这解决了问题。