先看效果圖
步驟一：
完成對主界面main.xml的創建：
<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context=".MainActivity">
<FrameLayout
android:id="@+id/fragment_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
/>
<RadioGroup
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/rg_group"
android:layout_alignParentBottom="true"
android:orientation="horizontal"
>
<RadioButton
android:id="@+id/rb_home"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:button="@null"
style="@style/fragment"
android:drawableTop="@drawable/rb_home_selector"
android:text="首頁"
/>
<RadioButton
android:id="@+id/rb_discover"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:button="@null"
style="@style/fragment"
android:drawableTop="@drawable/rb_discover_selector"
android:text="熱賣"
/>
<RadioButton
android:id="@+id/rb_cart"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:button="@null"
style="@style/fragment"
android:drawableTop="@drawable/rb_cart_selector"
android:text="購物車"
/>
<RadioButton
android:id="@+id/rb_user"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:button="@null"
style="@style/fragment"
android:drawableTop="@drawable/rb_user_selector"
android:text="我的"
/>
</RadioGroup>
</RelativeLayout>
radioButton中重復使用的樣式：被抽取出來在style中寫出
<style name="fragment">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">match_parent</item>
<item name="android:padding">5dp</item>
<item name="android:gravity">center</item>
<item name="android:textColor">@drawable/rb_text_color</item>
<item name="android:textSize">16sp</item>
<item name="android:textStyle">normal</item>
</style>
點擊RadioButton之后，導航欄文字顏色發生改變，宣告在drawable中
名字為：rb_text_color代碼如下：
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_selected="true" android:color="#FF0000"/>
<item android:color="#808080"/>
</selector>
導航欄圖示發生變化這里只寫其中一個其他三個都基本一樣：
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/icon_cartfill_press" android:state_selected="true" />
<item android:drawable="@drawable/icon_cart" />
</selector>
完成這些基本步驟之后，接下來就需要寫Fragment的布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center">
<TextView
android:id="@+id/tv_cart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="購物車"
android:textSize="30sp" />
</LinearLayout>
寫出其中一個另外三個類似，
之后后臺代碼中創建Fragment,這里也寫其中一個：CartFragment
package com.example.fragmentdemo;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
public class CartFragment extends Fragment {
private View view;
private TextView tv_home;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
if (view==null){
view = inflater.inflate(R.layout.cart_fragment,container,false);
}
return view;
}
}
步驟二：在MainActivity中，完成對fragment的切換功能
具體注釋已在代碼中給出，
package com.example.fragmentdemo;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import java.time.LocalDate;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {
private RadioButton rb_home,rb_discover,rb_cart,rb_user;
private RadioGroup rg_group;
private List<Fragment> fragments;
private int position=0;
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rb_home=findViewById(R.id.rb_home);
rb_discover=findViewById(R.id.rb_discover);
rb_cart=findViewById(R.id.rb_cart);
rb_user=findViewById(R.id.rb_user);
rg_group=findViewById(R.id.rg_group);
//默認選中第一個
rb_home.setSelected(true);
rg_group.setOnCheckedChangeListener(this);
//初始化fragment
initFragment();
//默認布局，選第一個
defaultFragment();
}
private void defaultFragment() {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fragment_layout,fragments.get(0));
transaction.commit();
}
private void setSelected() {
rb_home.setSelected(false);
rb_discover.setSelected(false);
rb_cart.setSelected(false);
rb_user.setSelected(false);
}
private void initFragment() {
fragments = new ArrayList<>();
fragments.add(0,new HomeFragment());
fragments.add(1,new DiscoverFragment());
fragments.add(2,new CartFragment());
fragments.add(3,new UserFragment());
}
@Override
public void onCheckedChanged(RadioGroup group, int i) {
//獲取fragment管理類物件
FragmentManager fragmentManager = getSupportFragmentManager();
//拿到fragmentManager的觸發器
FragmentTransaction transaction = fragmentManager.beginTransaction();
switch (i){
case R.id.rb_home:
position=0;
//呼叫replace方法，將fragment,替換到fragment_layout這個id所在UI，或者這個控制元件上面來
//這是創建replace這個事件，如果想要這個事件執行，需要把這個事件提交給觸發器
//用commit()方法
transaction.replace(R.id.fragment_layout,fragments.get(0));
//將所有導航欄設成默認色
setSelected();
rb_home.setSelected(true);
break;
case R.id.rb_discover:
position=1;
transaction.replace(R.id.fragment_layout,fragments.get(1));
//將所有導航欄設成默認色
setSelected();
rb_discover.setSelected(true);
break;
case R.id.rb_cart:
position=2;
transaction.replace(R.id.fragment_layout,fragments.get(2));
//將所有導航欄設成默認色
setSelected();
rb_cart.setSelected(true);
break;
case R.id.rb_user:
position=3;
transaction.replace(R.id.fragment_layout,fragments.get(3));
//將所有導航欄設成默認色
setSelected();
rb_user.setSelected(true);
break;
}
//事件的提交
transaction.commit();
}
}
這樣就完成了一個簡單的底部導航欄功能，這個只能通過點擊切換fragment，不能通過左右滑動去切換fragment，
轉載請註明出處，本文鏈接：https://www.uj5u.com/qita/286214.html
標籤：其他