PageViewer内部的GridView具有滞后滚动功能

Question

我实现了一个GridView内部PageViewer,但滚动并不像它应该的那样平滑.里面GridView的意见是拦截的接触.

这让我抓狂,我已经尝试了所有的东西,虽然有一件事情起作用,但最终并不是一个好的解决方案.首先是我的代码.

apps_grid.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <GridView
        android:id="@+id/appGrid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/ic_launcher_background"
        android:horizontalSpacing="4dp"
        android:numColumns="4"
        android:paddingTop="10dp"
        android:stretchMode="columnWidth"
        android:verticalSpacing="15dp"/>
</LinearLayout>

app_item.xml

<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="wrap_content"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/icon"
        android:layout_width="54dp"
        android:layout_height="54dp"
        android:layout_gravity="center_horizontal"
        android:src="@mipmap/ic_launcher" />

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="5dp"
        android:ellipsize="end"
        android:gravity="center"
        android:paddingEnd="15dp"
        android:paddingStart="15dp"
        android:singleLine="true"
        android:text="title"
        android:textColor="@android:color/white"
        android:textSize="14sp" />

</LinearLayout>

activity_main.xml中

<android.support.v4.view.ViewPager
    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:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginTop="45dp"
    android:fillViewport="true"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    />

AppModel.java

public class AppModel {

    private String label;
    private String pkg;
    private Drawable mIcon;

    public AppModel(String name, String pkg, Drawable icon) {
        this.label = name;
        this.pkg = pkg;
        this.mIcon = icon;
    }

    public AppModel(String name) {
        this.label = name;
    }

    public String getLabel() {
        return this.label;
    }

    public String getPkg() {
        return this.pkg;
    }

    public Drawable getIcon() {
        return mIcon;
    }
}

AppListAdapter.java

public class AppListAdapter extends BaseAdapter {

    private ArrayList<AppModel> apps;
    private LayoutInflater layoutInflater;

    public AppListAdapter(Context context, ArrayList<AppModel> apps) {
        this.apps = apps;
        this.layoutInflater = LayoutInflater.from(context);
    }

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

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public Object getItem(int position) {
        AppModel app = apps.get(position);
        if(app == null) {
            return null;
        }

        return app;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        AppModel app = apps.get(position);

        if (convertView == null) {
            convertView = layoutInflater.inflate(R.layout.app_item, null);
        }

        if(app == null) {
            return convertView;
        }

        ((TextView)convertView.findViewById(R.id.text)).setText(app.getLabel());

        return convertView;
    }
}

TestPagerAdapter.java

public class TestPagerAdapter extends PagerAdapter {

    private Context mContext;
    private LayoutInflater inflater;
    private ArrayList<AppModel> apps;
    private int perPage = 12;

    public TestPagerAdapter(Context context) {
        this.mContext = context;
        this.inflater = LayoutInflater.from(context);
    }

    @Override
    public Object instantiateItem(ViewGroup parent, int position) {
        ViewGroup layout = (ViewGroup) inflater.inflate(R.layout.apps_grid, parent, false);

        ArrayList<AppModel> pageApps = getAppsForPage(position);

        if(pageApps == null) {
            return layout;
        }

        final GridView appGrid = (GridView) layout.findViewById(R.id.appGrid);
        final AppListAdapter gridAdapter = new AppListAdapter(mContext, pageApps);
        appGrid.setVerticalScrollBarEnabled(false);
        appGrid.setAdapter(gridAdapter);
        parent.addView(layout);

        return layout;
    }

    @Override
    public void destroyItem(ViewGroup parent, int position, Object view) {
        parent.removeView((View) view);
    }

    @Override
    public int getCount() {
        if(apps != null) {
            return (int) Math.ceil((double) apps.size() / perPage);
        } else {
            return 0;
        }
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == object;
    }

    public void setData(ArrayList<AppModel> data) {
        if(data != null) {
            this.apps = data;
        }
    }

    public ArrayList<AppModel> getAppsForPage(int page) {
        if(apps == null) {
            return null;
        }

        int size = apps.size();
        int offset = getOffset(page);

        ArrayList<AppModel> pageApps = new ArrayList<AppModel>(size);

        for(int i = 0; i < perPage; i++) {
            if(offset+i < size) {
                pageApps.add(apps.get(offset+i));
            }
        }

        return pageApps;
    }

    public int getOffset(int page) {
        return perPage*page;
    }

}

MainActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
    TestPagerAdapter mPAdapter = new TestPagerAdapter(this);
    viewPager.setAdapter(mPAdapter);

    ArrayList<AppModel> items = new ArrayList<AppModel>(20);

    for(int i=0;i<20;i++) {
        AppModel app = new AppModel(""+i);
        items.add(app);
    }
    mPAdapter.setData(items);
    mPAdapter.notifyDataSetChanged();
}

所以,这是我尝试的:我替换GridView为RecyclerView.在EVERY上添加了所有这些属性View

android:clickable="false"
android:contextClickable="false"
android:defaultFocusHighlightEnabled="false"
android:focusable="false"
android:focusableInTouchMode="false"
android:focusedByDefault="false"
android:isScrollContainer="false"
android:longClickable="false"
android:nestedScrollingEnabled="false"
android:overScrollMode="never"
android:touchscreenBlocksFocus="false"

重写OnTouchListener(和许多其他)GridView并返回true.可能尝试了一些我现在记不住的其他事情了.

唯一有用的是设置android:filterTouchesWhenObscured="true"属性,GridView而其他一些应用程序视图在顶部(所以条件"WhenObscured"满意)当我尝试这个时我ViewPager开始滚动非常顺利,在其他情况下它有时不滚动(可能在GridView截取它时) .

请注意,GridView最终内部的项目必须是可点击的.

UPDATE

https://github.com/mpa4hu/GridViewPager这是一个项目的github链接,模拟问题向前和向后滚动,手势类似于这张图片

Answer 1

回收者视图回收视图，并且在需要之前不会重新创建视图。它只是重新绑定视图。

RecyclerView 是作为 ListView 的改进而创建的，所以是的，您可以使用 ListView 控件创建附加列表，但使用 RecyclerView 更容易，因为它：

在向上/向下滚动时重用单元格 - 这可以通过在 listView 适配器中实现 View Holder 来实现，但它是可选的，而在 RecycleView 中它是编写适配器的默认方式。

将列表与其容器解耦 - 因此您可以在运行时通过设置LayoutManager轻松地将列表项放入不同的容器（ LinearLayout 、gridLayout）中。

例子：

mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
//or
mRecyclerView.setLayoutManager(new GridLayoutManager(this, 2));//number 
of columns in a grid layout

关于RecyclerView的内容还有很多，但我觉得主要就是这几点。

因此，总而言之，RecyclerView 是一种更灵活的控件，用于处理“列表数据”，它遵循关注点委托模式，并且只为自己留下一个任务 - 回收项目。

你可以在这里参考它的优点：RecyclerView over ListView