Android-----AppBarLayout 的使用

AppBarLayout效果:
当向下滑动屏幕是时 顶部就会出现
当向上滑动屏幕时 顶部就会折叠

向下滑动时: "

既然设置了ViewPager 那么我就需要几个Fragment碎片放进去
(实际有三个item 需要几个碎片就放几个item 我这里就给出一个做示范)
Item1:

接下来就到了Java代码的编写

Java代码:
先将fragment的类定义出来:
(需要几个fragment就写几个类,关联上对应的item布局)

Fragment1:

package org.wdan.test008;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
public class Fragment1 extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    //对应上我们的item1
        View view=inflater.inflate(R.layout.item1,container,false);
        return view;
    }
}

Activity:

package org.wdan.test008;
import android.os.Bundle;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;
import com.google.android.material.appbar.AppBarLayout;
import com.google.android.material.tabs.TabLayout;
import java.util.ArrayList;
import java.util.List;
public class AppBarLayoutActivity extends AppCompatActivity {
    private TabLayout tabs;
    private AppBarLayout appbar;
    private ViewPager viewPager;
    //标题
    String[] title={"新闻","财经","娱乐"};
    List fragments;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_app_bar_layout);
        initView();
        fragments.add(new Fragment1());
        fragments.add(new Fragment2());
        fragments.add(new Fragment3());
        //通过适配器给viewPager添加碎片,我们通过内部类的方式在下面写了一个自定义适配器MyFragmentAdapter
        viewPager.setAdapter(new MyFragmentAdapter(getSupportFragmentManager(),fragments));
        //关联viewPager与tablayout
        tabs.setupWithViewPager(viewPager);
    }
    private void initView() {
        fragments=new ArrayList();
        tabs = (TabLayout) findViewById(R.id.tabs);
        appbar = (AppBarLayout) findViewById(R.id.appbar);
        viewPager = (ViewPager) findViewById(R.id.viewPager);
    }
    //自定义适配器
    public class MyFragmentAdapter extends FragmentPagerAdapter {
        List list;
        public MyFragmentAdapter(FragmentManager fm,List list) {
            super(fm);
            this.list=list;
        }
        @Override
        public Fragment getItem(int position) {
            return list.get(position);
        }
        @Override
        public int getCount() {
            return list.size();
        }
//这个方法可将标题对应上碎片
        @Nullable
        @Override
        public CharSequence getPageTitle(int position) {
            return title[position];
        }
    }
}

完成啦,快去运行看一看吧!

爱敲代码的小怪兽idan 原创文章 8获赞 3访问量 403 关注 私信 展开阅读全文
作者：爱敲代码的小怪兽idan