写这个我们需要写四个fragment的布局，下面只给出其中一个布局的xml.
代码如下：
<?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:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:id="@+id/touxiang"
android:src="@mipmap/toupiao"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
接下来我们需要写四个相应的Fragment的实现类，同样拷贝4份，改用inflate加载Fragment即可。即，包含四个差不多一样的Fragment
fragment的实现：
public class Fragment1 extends Fragment {
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_center,null);
return view;
}
}
然后是activity的布局：一个Framelayout+RadioGroup包含四个RadioButton，代码如下：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent">
<FrameLayout
android:id="@+id/fragment_fragment"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp">
</FrameLayout>
<RadioGroup
android:id="@+id/fragmeng_radioGroup"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RadioButton
android:id="@+id/fragment_radioBtn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/radio_button_pic1"
android:gravity="center"
android:text="主页" />
<RadioButton
android:id="@+id/fragment_radioBtn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/radio_button_pic2"
android:gravity="center"
android:text="物业" />
<RadioButton
android:id="@+id/fragment_radioBtn3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/radio_button_pic3"
android:gravity="center"
android:text="发现" />
<RadioButton
android:id="@+id/fragment_radioBtn4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/radio_button_pic4"
android:gravity="center"
android:text="我的" />
</RadioGroup>
</LinearLayout>
最后写最重要的Activity的实现：
各个七零八落的小部件都已经准备到序了，现在只剩下这个主界面实现类把他们融合在一起，实现相应的效果了。FragmentActivity.java 的编写也很简单，直接看代码和注释就可以了，不多解释额：主要包含几个初始化方法、选中处理、隐藏所有Fragment的方法。
public class FragmentActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener{
private FragmentManager fragmentManager;
private RadioGroup radioGroup;
private Fragment fragment1, fragment2, fragment3, fragment4;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fragment);
initView();
initData();
}
public void initView() {
radioGroup = findViewById(R.id.fragmeng_radioGroup);
radioGroup.setOnCheckedChangeListener(this);
}
public void initData() {
//1-创建fragment管理器
fragmentManager = getFragmentManager();
radioGroup.check(R.id.fragment_radioBtn1);
}
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
//2-通过fragment管理器得到fragment事物
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
hideFragmentAll(fragmentTransaction);//隐藏所有framgnet
switch (checkedId) {
case R.id.fragment_radioBtn1:
//3-往事物里面添加fragment
if (fragment1 == null) {
fragment1 = new Fragment1();
fragmentTransaction.add(R.id.fragment_fragment, fragment1);
}
fragmentTransaction.show(fragment1);
break;
case R.id.fragment_radioBtn2:
if (fragment2 == null) {
fragment2 = new Fragment2();
fragmentTransaction.add(R.id.fragment_fragment, fragment2);
}
fragmentTransaction.show(fragment2);
break;
case R.id.fragment_radioBtn3:
if (fragment3 == null) {
fragment3 = new Fragment3();
fragmentTransaction.add(R.id.fragment_fragment, fragment3);
}
fragmentTransaction.show(fragment3);
break;
case R.id.fragment_radioBtn4:
if (fragment4 == null) {
fragment4 = new Fragment4();
fragmentTransaction.add(R.id.fragment_fragment, fragment4);
}
fragmentTransaction.show(fragment4);
break;
}
//4-提交事物
fragmentTransaction.commit();
}
//隐藏所有framgnet
public void hideFragmentAll(FragmentTransaction fragmentTransaction) {
if (fragment1 != null) fragmentTransaction.hide(fragment1);
if (fragment2 != null) fragmentTransaction.hide(fragment2);
if (fragment3 != null) fragmentTransaction.hide(fragment3);
if (fragment4 != null) fragmentTransaction.hide(fragment4);
}
}
到这里我们的功能就基本实现了，是不是还挺简单的。
注意：
Fragment相关类导入的时候是v4包还是app包！我们先导app的包，不对再导v4的包.
以上内容是小白给大家分享的Android程序开发之Fragment实现底部导航栏实例代码，希望对大家有所帮助！
源码下载地址： https://download.csdn.net/download/weixin_42267745/10439958