前言
之前講過TabLayout的基本屬性全解,但是對于TabLayout實現的導航欄仍是有諸多限制,例如不能任意設置text的文字大小,若導航中涉及到圖片的話,圖片只能簡單的設計到文字上方,所以布局方面仍是很受限制,為了解決這種情況,這篇文章就介紹TabLayout自定義tab,讓你導航欄隨心所欲的布局。
此篇文章將介紹以下內容:
- TabLayout庫的導入
- TabLayout自定義導航的實現
- 需要注意的地方
- 效果圖
一.TabLayout庫的導入
TabLayout屬于android的Design庫中的控件,所以需要在使用之前在項目的app對應的buildle.gradle中導入該庫
//TabLayout
implementation 'com.android.support:design:27.1.1'
implementation 'com.android.support:support-v4:27.1.1'
二.TabLayout自定義導航的實現
2.1 mainActivity對應的xml布局
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="com.android.testdemo.main.MainActivity">
<android.support.design.widget.TabLayout
android:id="@+id/tablayout"
android:layout_width="0dp"
android:layout_height="@dimen/dp_80"
app:tabMode="scrollable"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="5dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tablayout" />
</android.support.constraint.ConstraintLayout>
2.2 需要加載的Fragment的代碼
TabLayout和ViewPager實現的導航欄,肯定涉及到Fragment了,下面給出MyFragment.java代碼:
public class MyFragment extends AppFragment {
@BindView(R.id.tv_name)
TextView mTvName;
private String mName;
@Override
public void onCreate(@Nullable Bundle bundle) {
super.onCreate(bundle);
if(getArguments()!=null){
mName = getArguments().getString("text");
}
}
@Override
public int getContentViewId() {
return R.layout.fragment_my;
}
@Override
public void initData() {
mTvName.setText(mName);
}
@Override
public void setListener() {
}
@Override
protected void onVisible(boolean isFirstTimeLoad) {
}
@Override
protected void onInvisible() {
}
}
2.3 MyFragment對應的fragment_my.xml代碼
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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="com.android.testdemo.main.MainActivity">
<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
2.4 ViewPager對應的adapter,即TabFragmentAdapter代碼
package com.android.testdemo.function;
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.TextView;
import com.android.testdemo.R;
import java.util.List;
/**
* Title:
* Description:
* <p>
* Created by pei
* Date: 2018/12/12
*/
public class TabFragmentAdapter extends FragmentPagerAdapter {
private String[] mTitles;
private Context mContext;
private List<Fragment> mFragments;
public TabFragmentAdapter(List<Fragment> fragments, String[] titles, FragmentManager fm, Context context) {
super(fm);
this.mContext = context;
this.mFragments = fragments;
this.mTitles = titles;
}
@Override
public Fragment getItem(int position) {
return mFragments.get(position);
}
@Override
public int getCount() {
return mTitles.length;
}
@Override
public CharSequence getPageTitle(int position) {
return mTitles[position];
}
public View getTabView(int position) {
View view = LayoutInflater.from(mContext).inflate(R.layout.item_header, null);
TextView textView=view.findViewById(R.id.tv_header);
textView.setText(mTitles[position]);
return view;
}
}
當中getTabView(int position)即為自定義Tab的布局,這在mainActivity中會用到,這里給出自定義布局item_header.xml的代碼
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="horizontal"
tools:context="com.android.testdemo.main.MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitCenter"
android:src="@mipmap/ic_launcher"/>
<TextView
android:id="@+id/tv_header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="@dimen/dp_5"
android:textColor="@color/blue"
android:textSize="@dimen/sp_12"
android:gravity="center"/>
</LinearLayout>
2.5 MainActivity中的代碼
package com.android.testdemo.main;
import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.widget.TextView;
import com.android.testdemo.R;
import com.android.testdemo.base.BaseActivity;
import com.android.testdemo.function.TabFragmentAdapter;
import com.android.testdemo.utils.LogUtil;
import com.android.testdemo.utils.ToastUtil;
import java.util.ArrayList;
import java.util.List;
import butterknife.BindView;
public class MainActivity extends BaseActivity{
@BindView(R.id.tablayout)
TabLayout mTabLayout;
@BindView(R.id.viewPager)
ViewPager mViewPager;
private String mTitles[] = {
"上海", "頭條推薦", "生活", "娛樂八卦", "體育",
"段子", "美食", "電影", "科技", "搞笑",
"社會", "財經", "時尚", "汽車", "軍事",
"小說", "育兒", "職場", "萌寵", "游戲",
"健康", "動漫", "互聯網"};
private List<Fragment> mFragments;
private TabFragmentAdapter mTabFragmentAdapter;
@Override
public int getContentViewId() {
return R.layout.activity_main;
}
@Override
public void initData() {
mFragments = new ArrayList<>();
for (int i = 0; i < mTitles.length; i++) {
Fragment fragment = new MyFragment();
Bundle bundle = new Bundle();
bundle.putString("text", mTitles[i]);
fragment.setArguments(bundle);
mFragments.add(fragment);
}
mTabFragmentAdapter = new TabFragmentAdapter(mFragments, mTitles, getSupportFragmentManager(), mContext);
// mViewPager.setOffscreenPageLimit(mFragments.size());// 設置預加載Fragment個數
mViewPager.setOffscreenPageLimit(6);// 設置預加載Fragment個數
mViewPager.setAdapter(mTabFragmentAdapter);
mViewPager.setCurrentItem(0);// 設置當前顯示標簽頁為第一頁
// 將ViewPager和TabLayout綁定
mTabLayout.setupWithViewPager(mViewPager);
//設置自定義tab
for (int i = 0; i < mTabLayout.getTabCount(); i++){
TabLayout.Tab tab = mTabLayout.getTabAt(i);
if (tab != null) {
tab.setCustomView(mTabFragmentAdapter.getTabView(i));
}
}
//設置第一頁為選中狀態時的tab文字顏色為紅色
View view=mTabLayout.getTabAt(0).getCustomView();
TextView textView=view.findViewById(R.id.tv_header);
textView.setTextColor(Color.RED);
}
@Override
public void setListener() {
//監聽事件
mTabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
//選中了tab的邏輯
LogUtil.i("======我選中了====");
View view=tab.getCustomView();
TextView textView=view.findViewById(R.id.tv_header);
textView.setTextColor(Color.RED);
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
//未選中tab的邏輯
LogUtil.i("======我未被選中====");
View view=tab.getCustomView();
TextView textView=view.findViewById(R.id.tv_header);
textView.setTextColor(Color.BLUE);
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
//再次選中tab的邏輯
LogUtil.i("======我再次被選中====");
}
});
}
@Override
public void onClick(View v) {
super.onClick(v);
}
private void showShort(String msg){
ToastUtil.shortShow(mContext,msg);
}
}
三. 需要注意的地方
- 可以在item_header.xml中自定義你想要的布局
- 在MainActivity中,"設置自定義tab"的代碼必須在"將ViewPager和TabLayout綁定"的代碼之后執行,不然自定義布局不起效果
- mainActivity對應的xml中TabLayout控件的高度必須用一個固定值,不能用wrap_content,不然會不起效果
mViewPager.setCurrentItem(0);// 設置當前顯示標簽頁為第一頁
設置的初始項要和
//設置第一頁為選中狀態時的tab文字顏色為紅色
View view=mTabLayout.getTabAt(0).getCustomView();
TextView textView=view.findViewById(R.id.tv_header);
textView.setTextColor(Color.RED);
設置的初始項保持一致
- 在 mTabLayout.addOnTabSelectedListener方法中要記得設置導航文字的選中和未選中文字顏色,當然在item_header.xml中要給text設置一個初始textcolor。
四.效果圖
效果圖.gif
ok,今天的內容就到這里了。