这次使用Fragment 与ViewPager2,Android --ViewPager2 基础学习–滑动效果有所介绍,Fristappbuild.gradle中的dependencies{}添加viewpager2依赖包,最终代码res/layout/fragment_blank.xml,对应的类java/com/pha/second/BlankFragment.java,暂不修改,新增Adapter继承FragmentStateAdapter
最终代码 java/com/pha/second/adapter/FragmentPager2Adapter.java,备注
其实,FragmentPager2Adapter方法是默认两个参数,第三个为了传进Fragment新增的,修改java/com/pha/second/BlankFragment.java
默认新增的BlankFragment.java 是传两个参数。现在改为一个,界面没有那么复杂,所以就留一个就可以了。然后将参数复制到fragment_blank.xml的TextView中
最终代码 java/com/pha/second/BlankFragment.java,java/com/pha/second/MainActivity.java
定义Fragment数组,初始化frag_List_Data,并在onCreate 调用,java/com/pha/second/MainActivity.java中onCreate 增加,==========至此界面可以实现Fragment的左右滑动,新增布局res/layout/bottom_tab.xml,
由于底部菜单栏还有选中效果所以
增加样式
res/drawable/tab_message_normal.png
res/drawable/tab_message_pressed.png
res/drawable/tab_menu_message.xml,备注: 其他几个图标同样如此,最终代码res/layout/activity_main.xml,java/com/pha/second/MainActivity.java中onCreate 增加,主界面 java/com/pha/second/MainActivity.java 增加继承View.OnClickListener
在onCreat 中引用InitEvent(),java/com/pha/second/MainActivity.java 新增ChangeFragment();,**最终代码java/com/pha/second/MainActivity.java **,
,
可能学习中有许多不对,可以再评论中指出,共同进步
主要是使用Fragment 与ViewPager2做的实践,实现类似WX 或ZFB的界面
其实之前在ViewPage的动态加载已经有过类似功能,使用的是ViewPage 和LinearLayout
这次使用Fragment 与ViewPager2
Android --ViewPager2 基础学习–滑动效果有所介绍
引入ViewPager2依赖包Fristappbuild.gradle中的dependencies{}添加viewpager2依赖包
//添加 ViewPager2 的依赖包 implementation 'androidx.viewpager2:viewpager2:1.0.0'主Layout 增加ViewPager2控件
2、子布局Fragment- -BlankFragment
最终代码res/layout/fragment_blank.xml
对应的类java/com/pha/second/BlankFragment.java,暂不修改
3、ViewPager2的Adapter新增Adapter继承FragmentStateAdapter
最终代码 java/com/pha/second/adapter/FragmentPager2Adapter.java
package com.pha.second.adapter; import androidx.annotation.NonNull; import androidx.fragment.app.Fragment; import androidx.fragment.app.FragmentManager; import androidx.lifecycle.Lifecycle; import androidx.viewpager2.adapter.FragmentStateAdapter; import java.util.List; public class FragmentPager2Adapter extends FragmentStateAdapter { private List fragmentList; public FragmentPager2Adapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle,List fragments) { super(fragmentManager, lifecycle); fragmentList = fragments; } @NonNull @Override public Fragment createFragment(int position) { return fragmentList.get(position); } @Override public int getItemCount() { //返回 Fragment的数量 return fragmentList.size(); } }
备注
其实,FragmentPager2Adapter方法是默认两个参数,第三个为了传进Fragment新增的
修改java/com/pha/second/BlankFragment.java
默认新增的BlankFragment.java 是传两个参数。现在改为一个,界面没有那么复杂,所以就留一个就可以了。然后将参数复制到fragment_blank.xml的TextView中
最终代码 java/com/pha/second/BlankFragment.java
package com.pha.second; import android.os.Bundle; import androidx.fragment.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; public class BlankFragment extends Fragment { // TODO: Rename parameter arguments, choose names that match // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER private static final String ARG_PARAM1 = "param1"; // TODO: Rename and change types of parameters private String mText; private View root; public BlankFragment() { // Required empty public constructor } // TODO: Rename and change types and number of parameters public static BlankFragment newInstance(String param1) { BlankFragment fragment = new BlankFragment(); Bundle args = new Bundle(); args.putString(ARG_PARAM1, param1); fragment.setArguments(args); return fragment; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (getArguments() != null) { mText = getArguments().getString(ARG_PARAM1); } } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if(root == null){ root = inflater.inflate(R.layout.fragment_blank, container, false); } TextView tv_bf_one = root.findViewById(R.id.tv_bf_one); tv_bf_one.setText(mText); return root; } }
java/com/pha/second/MainActivity.java
定义Fragment数组
private List frag_List_Data=new ArrayList<>();
初始化frag_List_Data,并在onCreate 调用
private void InitFragment() { frag_List_Data.add(new BlankFragment().newInstance("微信")); frag_List_Data.add(new BlankFragment().newInstance("通讯录")); frag_List_Data.add(new BlankFragment().newInstance("发现")); frag_List_Data.add(new BlankFragment().newInstance("我")); }5、展示ViewPager2
java/com/pha/second/MainActivity.java中onCreate 增加
vp2_one = findViewById(R.id.vp2_one); FragmentPager2Adapter fragmentPager2Adapter = new FragmentPager2Adapter(getSupportFragmentManager(), getLifecycle(), frag_List_Data); vp2_one.setAdapter(fragmentPager2Adapter);
==========至此界面可以实现Fragment的左右滑动
6、新增wx底部菜单栏新增布局res/layout/bottom_tab.xml
由于底部菜单栏还有选中效果所以
增加样式
res/drawable/tab_message_normal.png
res/drawable/tab_message_pressed.png
res/drawable/tab_menu_message.xml
备注: 其他几个图标同样如此
7、主Layout引入底部菜单栏最终代码res/layout/activity_main.xml
8、增加ViewPager2的监听事件
java/com/pha/second/MainActivity.java中onCreate 增加
vp2_one.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() { @Override public void onPageSelected(int position) { ChangeFragment(position); } });9、增加底部菜单栏的点击监听事件
主界面 java/com/pha/second/MainActivity.java 增加继承View.OnClickListener
在onCreat 中引用InitEvent()
private void InitEvent() { iv_one = findViewById(R.id.iv_one); iv_two = findViewById(R.id.iv_two); iv_three = findViewById(R.id.iv_three); iv_four = findViewById(R.id.iv_four); cur_iv = iv_one; findViewById(R.id.ll_one).setOnClickListener(this); findViewById(R.id.ll_two).setOnClickListener(this); findViewById(R.id.ll_three).setOnClickListener(this); findViewById(R.id.ll_four).setOnClickListener(this); } @Override public void onClick(View view) { ChangeFragment(view.getId()); }10、监听事件的方法(8、9中使用)
java/com/pha/second/MainActivity.java 新增ChangeFragment();
private void ChangeFragment(int position) { cur_iv.setSelected(false); switch (position){ case R.id.ll_one: vp2_one.setCurrentItem(0); case 0: iv_one.setSelected(true); cur_iv = iv_one; break; case R.id.ll_two: vp2_one.setCurrentItem(1); case 1: iv_two.setSelected(true); cur_iv = iv_two; break; case R.id.ll_three: vp2_one.setCurrentItem(2); case 2: iv_three.setSelected(true); cur_iv = iv_three; break; case R.id.ll_four: vp2_one.setCurrentItem(3); case 3: iv_four.setSelected(true); cur_iv = iv_four; break; default: break; } }
**最终代码java/com/pha/second/MainActivity.java **
package com.pha.second; import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.Fragment; import androidx.viewpager2.widget.ViewPager2; import android.os.Bundle; import android.view.View; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.Switch; import com.pha.second.adapter.FragmentPager2Adapter; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity implements View.OnClickListener{ private ViewPager2 vp2_one; private List frag_List_Data=new ArrayList<>(); private ImageView iv_one,iv_two,iv_three,iv_four,cur_iv; private LinearLayout ll_one,ll_two,ll_three,ll_four; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); InitEvent(); InitFragment(); vp2_one = findViewById(R.id.vp2_one); FragmentPager2Adapter fragmentPager2Adapter = new FragmentPager2Adapter(getSupportFragmentManager(), getLifecycle(), frag_List_Data); vp2_one.setAdapter(fragmentPager2Adapter); vp2_one.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() { @Override public void onPageSelected(int position) { ChangeFragment(position); } }); } private void ChangeFragment(int position) { cur_iv.setSelected(false); switch (position){ case R.id.ll_one: vp2_one.setCurrentItem(0); case 0: iv_one.setSelected(true); cur_iv = iv_one; break; case R.id.ll_two: vp2_one.setCurrentItem(1); case 1: iv_two.setSelected(true); cur_iv = iv_two; break; case R.id.ll_three: vp2_one.setCurrentItem(2); case 2: iv_three.setSelected(true); cur_iv = iv_three; break; case R.id.ll_four: vp2_one.setCurrentItem(3); case 3: iv_four.setSelected(true); cur_iv = iv_four; break; default: break; } } private void InitFragment() { frag_List_Data.add(new BlankFragment().newInstance("微信")); frag_List_Data.add(new BlankFragment().newInstance("通讯录")); frag_List_Data.add(new BlankFragment().newInstance("发现")); frag_List_Data.add(new BlankFragment().newInstance("我")); } private void InitEvent() { iv_one = findViewById(R.id.iv_one); iv_two = findViewById(R.id.iv_two); iv_three = findViewById(R.id.iv_three); iv_four = findViewById(R.id.iv_four); cur_iv = iv_one; findViewById(R.id.ll_one).setOnClickListener(this); findViewById(R.id.ll_two).setOnClickListener(this); findViewById(R.id.ll_three).setOnClickListener(this); findViewById(R.id.ll_four).setOnClickListener(this); } @Override public void onClick(View view) { ChangeFragment(view.getId()); } }效果图