[英]How can I implement the bottom navigation bar into an app for android?
這是一段Java代碼。 當我在BottomNavigationView
點擊一個項目時,Android應用程序停止BottomNavigationView
,它將打開一個片段。
public class MainActivity extends AppCompatActivity {
private BottomNavigationView bottomNavigationView;
private BottomNavigationView bottomNavigationView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottomNavigationView);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
與if-then和if-then-else語句不同,switch語句可以具有許多可能的執行路徑:
switch (item.getItemId()) {
case R.id.item0:
transaction.replace(R.id.content, new Item0_Fragment()).commit();
return true;
case R.id.item1:
transaction.replace(R.id.content, new Item1_Fragment()).commit();
return true;
case R.id.item2:
transaction.replace(R.id.content, new Item2_Fragment()).commit();
return true;
case R.id.item3:
transaction.replace(R.id.content, new Item3_Fragment()).commit();
return true;
}
return false;
}
});
}
首先,您確實兩次聲明了BottomNavigationView。 第二,您沒有編寫完整的代碼,而忽略了可能很重要的部分。 但是我確實為此編寫了代碼。 嘗試閱讀我的代碼,或者只是復制並粘貼。 您只需要創建片段,如果需要幫助,請告訴我。
MainActivity.java
public class MainActivity extends AppCompatActivity {
List<Fragment> fragmentList;
MyAdapter myAdapter;
ViewPager viewPager;
BottomNavigationView bottomNavigationView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.i(TAG,"onCreate()");
fragmentList = new ArrayList<>();
fragmentList.add(new Fragment1());
fragmentList.add(new Fragment2());
bottomNavigationView = findViewById(R.id.bottomNavigationView);
viewPager = findViewById(R.id.viewPagerAppActivity);
myAdapter = new MyAdapter(getSupportFragmentManager());
viewPager.setAdapter(myAdapter);
viewPager.setCurrentItem(0);
bottomNavigationView.setOnNavigationItemSelectedListener(botNavViewItemSelectedListener());
}
public BottomNavigationView.OnNavigationItemSelectedListener botNavViewItemSelectedListener() {
return new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.itemFragment1:
viewPager.setCurrentItem(0);
break;
case R.id.itemFragment2:
viewPager.setCurrentItem(1);
break;
}
return true;
}
};
}
public class MyAdapter extends FragmentStatePagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
@Override
public int getCount() {
return fragmentList.size();
}
}
}
activity_main.xml
<android.support.constraint.ConstraintLayout android:layout_width="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<android.support.v4.view.ViewPager
android:id="@+id/viewPagerAppActivity"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@id/bottomNavigationView"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginBottom="0dp"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="0dp"
app:layout_constraintVertical_bias="1.0" />
<android.support.design.widget.BottomNavigationView
app:menu="@menu/menu_bottom"
android:id="@+id/bottomNavigationView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:itemBackground="@color/colorPrimary"
app:itemIconTint="@drawable/bottom_bar_item_selector"
app:itemTextColor="@drawable/bottom_bar_item_selector"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent" />
</android.support.constraint.ConstraintLayout>
menu_bottom.xml填充我的導航菜單
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item android:id="@+id/itemFragment1" android:title="Frag1" android:enabled="true" app:showAsAction="always|withText" android:icon="@mipmap/ic_launcher"/>
<item android:id="@+id/itemFragment2" android:title="Frag2" android:enabled="true" app:showAsAction="always|withText" android:icon="@mipmap/ic_launcher"/>
</menu>
*有關片段,請點擊此http://www.truiton.com/2017/01/android-bottom-navigation-bar-example/
*活動
下面的代碼使活動底部導航(就像碎片一樣)
步驟1:創建一個BaseActivity並將其命名為BaseActivity
BaseActivity.java
public abstract class BaseActivity extends AppCompatActivity implements
BottomNavigationView.OnNavigationItemSelectedListener{
protected BottomNavigationView navigationView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(getContentViewId());
navigationView = findViewById(R.id.navigation);
navigationView.setOnNavigationItemSelectedListener(this);
BottomNavigationViewHelper.disableShiftMode(navigationView);
}
@Override
protected void onStart() {
super.onStart();
updateNavigationBarState();
}
@Override
public void onPause() {
super.onPause();
}
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
int itemId = item.getItemId();
if (itemId == R.id.menuBuilding) {
startActivity(new Intent(this, ActivityA.class));
} else if (itemId == R.id.menuChat) {
startActivity(new Intent(this, ActivityB.class));
} else if (itemId == R.id.menuProfile) {
startActivity(new Intent(this, ActivityC.class));
}
overridePendingTransition(0, 0);
finish();
return true;
}
private void updateNavigationBarState() {
int actionId = getNavigationMenuItemId();
selectBottomNavigationBarItem(actionId);
}
void selectBottomNavigationBarItem(int itemId) {
Menu menu = navigationView.getMenu();
for (int i = 0, size = menu.size(); i < size; i++) {
MenuItem item = menu.getItem(i);
boolean shouldBeChecked = item.getItemId() == itemId;
if (shouldBeChecked) {
item.setChecked(true);
break;
}
}
}
abstract int getContentViewId();
abstract int getNavigationMenuItemId();
}
步驟2:創建一個子活動並將其命名為ActivityA,然后復制並粘貼以下代碼
ActivityA.java
public class ActivityA extends BaseActivity implements {
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
int getContentViewId() {
return R.layout.activity_a_layout;
}
@Override
int getNavigationMenuItemId() {
return R.id.menuBuilding;
}
}
類似地創建ActivityB.java
和ActivityC.java
這兩個類都類似於ActivityA.java,但是不同的是ActivityA.java
返回
@Override
int getNavigationMenuItemId() {
return R.id.menuBuilding;
}
和
ActivityB.java
返回
@Override
int getNavigationMenuItemId() {
return R.id.menuChat;
}
和
ActivityC.java
返回`
@Override
int getNavigationMenuItemId() {
return R.id.menuProfile;
}
還為兩個Java類創建布局,然后將activity_a_layout.xml
代碼復制粘貼到ActivityB.java
和ActivityC.java
兩種布局中
步驟3:創建一個名為activity_a_layout的布局,並復制粘貼以下代碼
'activity_a_layout.xml'
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/toolbar"
android:background="@android:color/white">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Coming soon..."
android:textSize="19sp"
android:textStyle="bold"
android:layout_centerInParent="true"/>
</RelativeLayout>
<include
android:id="@+id/navigation"
layout="@layout/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true" />
</RelativeLayout>
第四步:
創建一個名為bottom_navigation的布局,並復制以下代碼
bottom_navigation.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.BottomNavigationView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/dark_grey"
app:itemIconTint="@drawable/nav_item_menu_selector"
app:itemTextColor="@drawable/nav_item_menu_selector"
app:menu="@menu/bottom_nav_items" />
步驟5:在res內部創建一個菜單文件夾,並在菜單內部創建一個名為bottom_nav_items的文件,然后復制並粘貼以下代碼
bottom_nav_items.xml
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="@+id/menuChat"
android:icon="@drawable/ic_chat"
android:title="Chat" />
<item
android:id="@+id/menuBuilding"
android:icon="@drawable/ic_building_white"
android:title="Company" />
<item
android:id="@+id/menuProfile"
android:icon="@drawable/menu_item_profile"
android:title="Profile"
app:itemTextColor="@android:color/transparent" />
</menu>
**不要忘記在清單中聲明ActivityA.java
, ActivityB.java
和ActivityC.java
快樂編碼
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