当我选择其他项目时，BottomNavigationView 中的第一项保持高亮显示

问题描述

导航栏中的第一项一直高亮显示.

The first item in the navigation bar keep highlighting.

当我点击导航栏上的其他项目时，内容会发生变化，但不会突出显示相应的项目，继续突出显示第一项.

When I click other item on the navigation bar, the content will change but the corresponding item will not be highlighted, just keep highlighting the first item.

        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            Fragment fragment=null;
            switch (item.getItemId()){
                case R.id.number:
                    fragment=new data();
                    break;
                case R.id.graph:
                    fragment=new graph();
                    break;
            }
            FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.replace(R.id.content_drawer, fragment);
            fragmentTransaction.commit();
            return true;
        }
    });

这是听众

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>

<android.support.design.widget.BottomNavigationView
    android:id="@+id/navigation"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/colorPrimaryDark"
    android:layout_alignParentBottom="true"
    android:layout_gravity="bottom"
    app:menu="@menu/navigation" />

<LinearLayout
    android:id="@+id/graphlayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@id/navigation"
    android:orientation="vertical"
    android:gravity="center_vertical">

</LinearLayout>
</RelativeLayout>

这是xml

<?xml version="1.0" encoding="utf-8"?>

<item
    android:id="@+id/number"
    android:title="number"
    android:checkable="true"/>

<item
    android:id="@+id/graph"
    android:title="graph"
    android:checkable="true"/>

</menu>

这是meun.xml

推荐答案

这通常发生的原因是 onNavigationItemSelected 方法返回 false 值.您可以通过在 onNavigationItemSelected 方法中删除除 return true 之外的所有代码来检查这一点.就这样;

This usually happens beacause of when onNavigationItemSelected method return false value. You can check this with remove all code except return true inside the onNavigationItemSelected method. Just like this;

bottomNavigationView.setOnNavigationItemSelectedListener(new
BottomNavigationView.OnNavigationItemSelectedListener() {
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
       return true;
    }
});

然后你会看到它可以工作，但内容没有改变.对于内容更改，如果我是你，我会像这样将默认返回值更改为 false；

Then you'll see it works but the content was not changed. For change with content, If I were you I'll change the default return value as false like this;

bottomNavigationView.setOnNavigationItemSelectedListener(new
BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()){
            case R.id.number:
               //Open fragment or do whatever you want.
               return true;
            case R.id.graph:
               //Open another fragment or do whatever you want.
               return true;
        }
    return false;
}
});

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