效果图
嗯…首页常用2种Fragment切换一种是利用Fragment的hide,show来切换,另一种则直接将Fragment放在viewpager里,通过切换viewpager的item来实现。
这里配合RadioGroup实现,代码:
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.widget.RadioGroup;
import butterknife.Bind;
import butterknife.ButterKnife;
public class RadioGroupActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {
private Fragment1 fragment1;
private Fragment2 fragment2;
private Fragment3 fragment3;
private Fragment4 fragment4;
@Bind(R.id.rg)
RadioGroup radioGroup;
private FragmentManager fragmentManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_radio_group);
ButterKnife.bind(this);
fragmentManager = getSupportFragmentManager();
//默认选中第一个tab
showFragment(1);
radioGroup.check(R.id.rb_1);
radioGroup.setOnCheckedChangeListener(this);
}
private void showFragment(int page) {
FragmentTransaction ft = fragmentManager.beginTransaction();
// 想要显示一个fragment,先隐藏所有fragment,防止重叠
hideFragments(ft);
switch (page) {
case 1:
// 如果fragment1已经存在则将其显示出来
if (fragment1 != null)
ft.show(fragment1);
// 否则添加fragment1,注意添加后是会显示出来的,replace方法也是先remove后add
else {
fragment1 = new Fragment1();
ft.add(R.id.fl_content_main, fragment1);
}
break;
case 2:
if (fragment2 != null)
ft.show(fragment2);
else {
fragment2 = new Fragment2();
ft.add(R.id.fl_content_main, fragment2);
}
break;
case 3:
if (fragment3 != null) {
ft.show(fragment3);
}
else {
fragment3 = new Fragment3();
ft.add(R.id.fl_content_main, fragment3);
}
break;
case 4:
if (fragment4 != null){
ft.show(fragment4);
}
else {
fragment4 = new Fragment4();
ft.add(R.id.fl_content_main, fragment4);
}
break;
}
ft.commit();
}
// 当fragment已被实例化,相当于发生过切换,就隐藏起来
public void hideFragments(FragmentTransaction ft) {
if (fragment1 != null)
ft.hide(fragment1);
if (fragment2 != null)
ft.hide(fragment2);
if (fragment3 != null)
ft.hide(fragment3);
if (fragment4 != null)
ft.hide(fragment4);
}
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.rb_1:
showFragment(1);
break;
case R.id.rb_2:
showFragment(2);
break;
case R.id.rb_3:
showFragment(3);
break;
case R.id.rb_4:
showFragment(4);
break;
}
}
}
布局xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_radio_group"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/fl_content_main"
android:layout_width="match_parent"
android:layout_height="0dip"
android:layout_weight="1"
android:orientation="vertical" >
LinearLayout>
<RadioGroup
android:layout_centerVertical="true"
android:id="@+id/rg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingTop="5dp"
android:paddingBottom="5dp">
<RadioButton
android:id="@+id/rb_1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/homepage_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="首页"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/faxian_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="发现"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/message_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="消息"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/wo_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="我"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
RadioGroup>
LinearLayout>
文字颜色选择textcolor_bottom_main.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_checked="true" android:color="#F64358" />
<item android:state_checked="false" android:color="#93929A"/>
selector>
radioButton选中状态,这里只展示一个,其他的一样homepage_btn_bg.xml
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/chomepage" android:state_checked="true">item>
<item android:drawable="@drawable/homepage" android:state_checked="false">item>
selector>
实现思路,当选中某个radioButton的时候,1 先判断所有的Fragment是否存在,若存在则隐藏 hideFragments(ft) ;2 判断该radioButton对应的Fragment是否存在,若存在则show, 不存在则new出来add进FragmentTransaction里,这里不需要再show了,因为存在的页面都已经hide了,直接add进来的会显示出来。 这样实现的好处是,当你为切换到某个按钮时,这个按钮对应的Fragment是不会加载的。
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioGroup;
import java.util.ArrayList;
import java.util.List;
import butterknife.Bind;
import butterknife.ButterKnife;
public class ViewPagerActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener, RadioGroup.OnCheckedChangeListener {
private Fragment1 fragment1;
private Fragment2 fragment2;
private Fragment3 fragment3;
private Fragment4 fragment4;
@Bind(R.id.rg)
RadioGroup rg;
@Bind(R.id.viewpager)
ViewPager viewPager;
ViewPagerAdapter viewPagerAdapter;
Listfragments=new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_pager);
ButterKnife.bind(this);
initViewPager();
}
private void initViewPager() {
fragment1=new Fragment1();
fragment2=new Fragment2();
fragment3=new Fragment3();
fragment4=new Fragment4();
fragments.add(fragment1);
fragments.add(fragment2);
fragments.add(fragment3);
fragments.add(fragment4);
viewPagerAdapter=new ViewPagerAdapter(getSupportFragmentManager(),fragments);
viewPager.setAdapter(viewPagerAdapter);
viewPager.addOnPageChangeListener(this);
//默认选中第一个
rg.check(R.id.rb_1);
rg.setOnCheckedChangeListener(this);
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
switch (position){
case 0:
rg.check(R.id.rb_1);
break;
case 1:
rg.check(R.id.rb_2);
break;
case 2:
rg.check(R.id.rb_3);
break;
case 3:
rg.check(R.id.rb_4);
break;
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.rb_1:
viewPager.setCurrentItem(0);
break;
case R.id.rb_2:
viewPager.setCurrentItem(1);
break;
case R.id.rb_3:
viewPager.setCurrentItem(2);
break;
case R.id.rb_4:
viewPager.setCurrentItem(3);
break;
}
}
}
adapter代码
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import java.util.ArrayList;
import java.util.List;
/**
* Created by KID on 2017/8/10 0010.
*/
public class ViewPagerAdapter extends FragmentPagerAdapter {
List fragments=new ArrayList<>();
public ViewPagerAdapter(FragmentManager fm, List fragments) {
super(fm);
this.fragments = fragments;
}
@Override
public int getCount() {
return fragments.size();
}
@Override
public Fragment getItem(int position) {
return fragments.get(position);
}
}
布局activity_view_pager.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"/>
<RadioGroup
android:layout_centerVertical="true"
android:id="@+id/rg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:paddingTop="5dp"
android:paddingBottom="5dp">
<RadioButton
android:id="@+id/rb_1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/homepage_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="首页"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/faxian_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="发现"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_3"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/message_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="消息"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
<RadioButton
android:id="@+id/rb_4"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:button="@null"
android:drawableTop="@drawable/wo_btn_bg"
android:gravity="center_horizontal"
android:drawablePadding="6dp"
android:text="我"
android:textColor="@drawable/textcolor_bottom_main"
android:textSize="10sp" />
RadioGroup>
LinearLayout>
ViewPager+Fragment实现起来会暴力很多,因为ViewPager在setAdapter的时候,我们已经把所有的Fragment new出来放入adapter里了。嗯哼…..当然你可以new的时候不加载Fragment数据。把加载数据的方法 initData写在onPageSelected时获取当前选中item对应的Fragment去调用,这样也能实现选中才加载网络数据。
代码传送们http://download.csdn.net/download/qq_31390699/9954325