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ViewPager 与 Fragment相结合实现微信界面实例代码

时间:2021-07-19 08:00:27 | 栏目:Android代码 | 点击:

在如今的互联网时代,微信已是一个超级App。这篇通过ViewPager + Fragment实现一个类似于微信的界面,之前有用FragmentTabHost实现过类似界面,ViewPager的实现方式相对于FragmentTabHost的方式更简单明了。

ViewPager:

  ViewPager继承自ViewGroup,是一个容器类,可以往里添加View.

  ViewPager的使用很简单,通过setAdapter()方法设置一个PagerAdapter即可,这个PagerAdapter需要自己写,实现里面的一些方法。本篇要和Fragment结合,所以实现的是FragmentPagerAdapter类,FragmentPagerAdapter继承自PagerAdapter.

  ViewPager通过addOnPageChangeListener()方法可以设置一个ViewPager.OnPageChangeListener监听,当Pager发生变化时就调用相应的方法。

Fragment:

  Fragment有自己的生命周期, 有兴趣的可以自己通过各种方式研究下(自己打Log看是最简单的一种方式),这里就不在赘述。和ViewPager结合,有几个Pager就需要实现几个不同的Fragment.

先看一下最后实现的效果图:


布局上分为三部分:

  最上面的layout_top.xml,主要就是上面那个标题,就一个TextView,中间的ViewPager,最下面的layout_bottom.xml包括三个线性布局,每个线性布局包括一个ImageView和TextView.

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.administrator.viewpagerl.MainActivity">
<include layout="@layout/layout_top"></include>
<android.support.v4.view.ViewPager
android:id="@+id/ViewPagerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1">
</android.support.v4.view.ViewPager>
<include layout="@layout/layout_bottom"></include>
</LinearLayout>

layout_top.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="3dp"
android:paddingBottom="3dp"
android:background="@android:color/darker_gray">
<TextView
android:id="@+id/ViewTitle"
android:layout_marginLeft="20dp"
android:layout_marginTop="5dp"
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>

layout_bottom.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:paddingTop="3dp"
android:paddingBottom="3dp"
android:background="@android:color/holo_green_light">
<LinearLayout
android:id="@+id/firstLinearLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center_horizontal"
android:layout_weight="1">
<ImageView
android:id="@+id/firstImageView"
android:background="@drawable/tab_weixin"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/firstTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="微信"
/>
</LinearLayout>
<LinearLayout
android:id="@+id/secondLinearLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center_horizontal"
android:layout_weight="1">
<ImageView
android:id="@+id/secondImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/tab_setting"/>
<TextView
android:id="@+id/secondTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="朋友"
/>
</LinearLayout>
<LinearLayout
android:id="@+id/threeLinearLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center_horizontal"
android:layout_weight="1">
<ImageView
android:id="@+id/threeImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/tab_find"/>
<TextView
android:id="@+id/threeTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="发现"
/>
</LinearLayout>
</LinearLayout>

  上面有提到,ViewPager需要实现一个Pageradapter,很简单继承FragmentPagerAdapter,实现里面的getItem()和getCount()方法即可。

ViewPagerFragmentAdapter .java

package com.example.administrator.viewpagerl;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.util.Log;
import java.util.ArrayList;
import java.util.List;
public class ViewPagerFragmentAdapter extends FragmentPagerAdapter {
private List<Fragment> mList = new ArrayList<Fragment>();
public ViewPagerFragmentAdapter(FragmentManager fm , List<Fragment> list) {
super(fm);
this.mList = list;
}
@Override
public Fragment getItem(int position) {
return mList.get(position);
}
@Override
public int getCount() {
return mList != null ? mList.size() : 0;
}
}

  ViewPager的每个Pager都需要一个Fragment,Fragment会实例化布局,显示在ViewPager的每个Pager中

ChatFragment.java

package com.example.administrator.fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.example.administrator.viewpagerl.R;
public class ChatFragment extends Fragment {
View mView;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
if (mView == null) {
mView = inflater.inflate(R.layout.fragment_layout,null);
}
((TextView)mView.findViewById(R.id.mTextView)).setText("聊天界面");
return mView;
}
}

  这里需要三个Fragment,因为这里使用的布局很简单,三个布局基本是一致的,FriendFragment、FindFragment 这里就都不贴出代码了。微信里面的聊天列表,朋友列表都是在Fragment里面实例化的布局里有个ListView,通过ListView的方式实现的,这里只是为了记录ViewPager就没有实现那些,有兴趣的可以自己搞搞,其实也不难。

  在Activity里面只需要给ViewPager设置上面那个Adapter,设置一个监听知道Pager如何变化即可。点击最下面微信、朋友、发现三个按钮,通过ViewPager的setCurrentItem()方法就能跳转到对应的Pager,除了这些还有就是通过一些简单的逻辑,控制一下界面的改变就行,没有太难的东西。

MainActivity.java

package com.example.administrator.viewpagerl;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
import com.example.administrator.fragment.ChatFragment;
import com.example.administrator.fragment.FindFragment;
import com.example.administrator.fragment.FriendFragment;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "MainActivity.TAG";
TextView titleTextView;
public LinearLayout firstLinearLayout;
public LinearLayout secondLinearLayout;
public LinearLayout threeLinearLayout;
ViewPager mViewPager;
ViewPagerFragmentAdapter mViewPagerFragmentAdapter;
FragmentManager mFragmentManager;
String[] titleName = new String[] {"微信","朋友","发现"};
List<Fragment> mFragmentList = new ArrayList<Fragment>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mFragmentManager = getSupportFragmentManager();
setContentView(R.layout.activity_main);
initFragmetList();
mViewPagerFragmentAdapter = new ViewPagerFragmentAdapter(mFragmentManager,mFragmentList);
initView();
initViewPager();
}
@Override
protected void onResume() {
super.onResume();
}
public void initViewPager() {
mViewPager.addOnPageChangeListener(new ViewPagetOnPagerChangedLisenter());
mViewPager.setAdapter(mViewPagerFragmentAdapter);
mViewPager.setCurrentItem(0);
titleTextView.setText(titleName[0]);
updateBottomLinearLayoutSelect(true,false,false);
}
public void initFragmetList() {
Fragment chat = new ChatFragment();
Fragment friend = new FriendFragment();
Fragment find = new FindFragment();
mFragmentList.add(chat);
mFragmentList.add(friend);
mFragmentList.add(find);
}
public void initView() {
titleTextView = (TextView) findViewById(R.id.ViewTitle);
mViewPager = (ViewPager) findViewById(R.id.ViewPagerLayout);
firstLinearLayout = (LinearLayout) findViewById(R.id.firstLinearLayout);
firstLinearLayout.setOnClickListener(this);
secondLinearLayout = (LinearLayout) findViewById(R.id.secondLinearLayout);
secondLinearLayout.setOnClickListener(this);
threeLinearLayout = (LinearLayout) findViewById(R.id.threeLinearLayout);
threeLinearLayout.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.firstLinearLayout:
mViewPager.setCurrentItem(0);
updateBottomLinearLayoutSelect(true,false,false);
break;
case R.id.secondLinearLayout:
mViewPager.setCurrentItem(1);
updateBottomLinearLayoutSelect(false,true,false);
break;
case R.id.threeLinearLayout:
mViewPager.setCurrentItem(2);
updateBottomLinearLayoutSelect(false,false,true);
break;
default:
break;
}
}
private void updateBottomLinearLayoutSelect(boolean f, boolean s, boolean t) {
firstLinearLayout.setSelected(f);
secondLinearLayout.setSelected(s);
threeLinearLayout.setSelected(t);
}
class ViewPagetOnPagerChangedLisenter implements ViewPager.OnPageChangeListener {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// Log.d(TAG,"onPageScrooled");
}
@Override
public void onPageSelected(int position) {
Log.d(TAG,"onPageSelected");
boolean[] state = new boolean[titleName.length];
state[position] = true;
titleTextView.setText(titleName[position]);
updateBottomLinearLayoutSelect(state[0],state[1],state[2]);
}
@Override
public void onPageScrollStateChanged(int state) {
Log.d(TAG,"onPageScrollStateChanged");
}
}
}

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