Andriod Studio学习笔记第八天

使用AppBarLayout实现程序栏布局
在上一篇TabLayout基础上增加顶部程序栏可收起和滚动显示多图
程序编写思路：
1.主界面AppBarLayout+NestedScrollView布局。
AppBarLayout=TabLayout+ToolBar在TabLayout基础上实现顶部程序栏可收起功能。NestedScrolView实现下拉进度条显示多幅图片。
2.其他与上一篇基本一致，创建3个XML，并通过Fragment加载。主程序覆写onCreate方法，创建FragmentPagerAdapter，动态调用Fragment。

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_height="wrap_content"
        android:layout_width="match_parent">

        <android.support.v7.widget.Toolbar
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:gravity="center"
            app:layout_scrollFlags="scroll|enterAlways">

            <ImageView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@mipmap/ic_launcher" />
        </android.support.v7.widget.Toolbar>

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            app:tabMinWidth="100dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|enterAlways"
            app:tabMode="scrollable">

        </android.support.design.widget.TabLayout>
    </android.support.design.widget.AppBarLayout>

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true"
        app:layout_behavior="android.support.design.widget.AppBarLayout$ScrollingViewBehavior">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            tools:context=".MainActivity">

            <android.support.v4.view.ViewPager
                android:id="@+id/view"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        </LinearLayout>
    </android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>

<?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:orientation="vertical"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:fillViewport="true">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <ImageView
                android:id="@+id/imageView9"
                android:layout_width="match_parent"
                android:layout_height="328dp"
                app:srcCompat="@drawable/ic_launcher_background" />

            <ImageView
                android:id="@+id/imageView10"
                android:layout_width="match_parent"
                android:layout_height="330dp"
                app:srcCompat="@mipmap/ic_launcher" />

            <ImageView
                android:id="@+id/imageView12"
                android:layout_width="match_parent"
                android:layout_height="264dp"
                app:srcCompat="@mipmap/ic_launcher_round" />

            <ImageView
                android:id="@+id/imageView13"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                tools:srcCompat="@tools:sample/backgrounds/scenic[0]" />

        </LinearLayout>
    </android.support.v4.widget.NestedScrollView>

</LinearLayout>

package com.example.wxt.appbarlayout;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MyFragment2 extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view1 = inflater.inflate(R.layout.layout_page2,container,false);
        return view1;
    }
}

package com.example.wxt.appbarlayout;

import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    TabLayout tabLayout;
    ViewPager viewPager;
    List<Fragment>fragments;
    String[]title={"新闻","财经","文学"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tabLayout=findViewById(R.id.tabs);
        viewPager=findViewById(R.id.view);
        fragments= new ArrayList<>();
        fragments.add(new MyFragment1());
        fragments.add(new MyFragment2());
        fragments.add(new MyFragment3());

        adapter myadpter = new adapter(getSupportFragmentManager(),fragments);
        viewPager.setAdapter(myadpter);
        tabLayout.setupWithViewPager(viewPager);

    }
    private class adapter extends FragmentPagerAdapter{
        private List<Fragment> list;
        public adapter(FragmentManager fm,List<Fragment> list) {
            super(fm);
            this.list = list;
        }

        @Override
        public Fragment getItem(int position) {
            return list.get(position);
        }

        @Override
        public int getCount() {
            return list.size();
        }

        @Nullable
        @Override
        public CharSequence getPageTitle(int position) {
            return title[position];
        }
    }
}