Fragment和BottomNavigationview实现导航布局
思路分析
实现导航栏有很多思路,一种比较简单的方法是使用 Fragment 和 BottomNavigationView 实现
- Activity 作为 Fragment 的宿主
- BottomNavigationview 作为底部 tab 用来切换
- Framelayout 作为 Fragment 的容器
- FragmentManager (FragmentTransaction) 作为隐藏和显示的开关
思路很简单,实现起来也很简单,我看到 wanAndroid 这款 APP 就是使用这种思路做的导航栏
效果如下
代码
Activity
package me.tinuv.fragmentfornavi;
import android.os.Bundle;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
ArrayList<Fragment> fragments;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fragments = new ArrayList<>();
fragments.add(HomeFragment.newInstance());
fragments.add(DashBoardFragment.newInstance());
fragments.add(NoticeFragment.newInstance());
BottomNavigationView navigation = findViewById(R.id.navigation);
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().add(R.id.fragment_container, fragments.get(0), "HOME")
.add(R.id.fragment_container, fragments.get(1), "DASHBOARD")
.add(R.id.fragment_container, fragments.get(2), "NOTICE")
.commit();
fm.beginTransaction()
.hide(fragments.get(1))
.hide(fragments.get(2))
.commit();
navigation.setOnNavigationItemSelectedListener((item) -> {
switch (item.getItemId()) {
case R.id.navigation_home:
fm.beginTransaction()
.hide(fragments.get(1))
.hide(fragments.get(2))
.show(fragments.get(0))
.commit();
return true;
case R.id.navigation_dashboard:
fm.beginTransaction()
.hide(fragments.get(0))
.hide(fragments.get(2))
.show(fragments.get(1))
.commit();
return true;
case R.id.navigation_notifications:
fm.beginTransaction()
.hide(fragments.get(0))
.hide(fragments.get(1))
.show(fragments.get(2))
.commit();
return true;
}
return false;
});
}
}
Fragment
很简单,没有太多东西
package me.tinuv.fragmentfornavi;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class HomeFragment extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.layout_home, container, false);
}
public static HomeFragment newInstance() {
return new HomeFragment();
}
}
布局
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity"
android:gravity="bottom">
<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="500dp">
</FrameLayout>
<android.support.design.widget.BottomNavigationView
android:id="@+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
app:menu="@menu/navigation" />
</LinearLayout>
????????正文结束????????