GridView有两列，第一项跨越两列 [英] GridView with two columns, first item spans both columns
问题描述
我有一个Imageview&一个gridview.
我的布局设计在这里.
我想将这两个视图合并为一个gridview
我的问题:
如何在两列中设置gridview首项跨度?
在研究您的问题时，我学到了一些新东西:我碰巧在GridLayoutManager中查找RecyclerView，并且注意到您可以设置自定义SpanSizeLookup允许您指定例如，项目0占用2列，项目1占用1列，等等.
事实证明，如果将RecyclerView与GridLayoutManager一起使用，则解决方案很简单:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create a grid layout with two columns
GridLayoutManager layoutManager = new GridLayoutManager(this, 2);
// Create a custom SpanSizeLookup where the first item spans both columns
layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return position == 0 ? 2 : 1;
}
});
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(new MyGridAdapter());
}
我创建了一个测试项目，只是为了对其进行尝试并确保它达到了我的预期效果，所以它就像一个魅力.
有关适配器的说明:RecyclerView.Adapter与ListAdapter不兼容.您需要从RecyclerView.Adapter扩展适配器并进行适当的更改.
这是我为测试项目创建的适配器:
public static class MyViewHolder extends RecyclerView.ViewHolder {
ImageView mImageView;
TextView mTextView;
public MyViewHolder(View itemView) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.imageView);
mTextView = (TextView) itemView.findViewById(R.id.textView);
}
}
public static class MyGridAdapter extends RecyclerView.Adapter<MyViewHolder> {
private int[] mDrawables;
public MyGridAdapter() {
this.mDrawables = new int[] {
R.drawable.images_01,
R.drawable.images_02,
.
.
.
};
}
@Override
public int getItemCount() {
return mDrawables.length;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.layout_grid_item, parent, false);
MyViewHolder holder = new MyViewHolder(view);
// set up any onClickListener you need on the view here
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.mImageView.setImageResource(mDrawables[position]);
holder.mTextView.setText("Image " + position);
}
}
首先，创建一个RecyclerView.ViewHolder子类.视图持有者模式现在是这种新的适配器视图方法不可或缺的组成部分.您的ViewHolder将为您的视图设置所有子视图.
然后在您的RecyclerView.Adapter子类中，覆盖onCreateViewHolder()和onBindViewHolder().在onCreateViewHolder()中，您可以扩展视图并构造ViewHolder.在onBindViewHolder()中，使用position获取适配器数据并使用ViewHolder设置子视图.因此RecyclerView从技术上回收包含View的ViewHolder.
一旦对适配器进行了更改，就应该准备就绪.
I have one Imageview & one gridview..
My layout design here..
I want to combine these two views into single gridview
my question:
How to set gridview first item spans in both columns?
In researching your question, I learned something new: I happened to look at GridLayoutManager for RecyclerView and I noticed that you can set a custom SpanSizeLookup. Now a "span" is just a column if you're scrolling vertically and a row if you're scrolling horizontally. So the SpanSizeLookup allows you to specify for example, item 0 takes 2 columns, item 1 takes 1 column, etc.
It turns out that if you use RecyclerView with a GridLayoutManager the solution is easy-peasy:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create a grid layout with two columns
GridLayoutManager layoutManager = new GridLayoutManager(this, 2);
// Create a custom SpanSizeLookup where the first item spans both columns
layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return position == 0 ? 2 : 1;
}
});
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(new MyGridAdapter());
}
I created a test project just to try it out and make sure it did what I expected it to, and it worked like a charm.
A note about the adapter: RecyclerView.Adapter is not compatible with ListAdapter. You need to extend your adapter from RecyclerView.Adapter and make the appropriate changes.
Here is the adapter I created for my test project:
public static class MyViewHolder extends RecyclerView.ViewHolder {
ImageView mImageView;
TextView mTextView;
public MyViewHolder(View itemView) {
super(itemView);
mImageView = (ImageView) itemView.findViewById(R.id.imageView);
mTextView = (TextView) itemView.findViewById(R.id.textView);
}
}
public static class MyGridAdapter extends RecyclerView.Adapter<MyViewHolder> {
private int[] mDrawables;
public MyGridAdapter() {
this.mDrawables = new int[] {
R.drawable.images_01,
R.drawable.images_02,
.
.
.
};
}
@Override
public int getItemCount() {
return mDrawables.length;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.layout_grid_item, parent, false);
MyViewHolder holder = new MyViewHolder(view);
// set up any onClickListener you need on the view here
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.mImageView.setImageResource(mDrawables[position]);
holder.mTextView.setText("Image " + position);
}
}
First, create a RecyclerView.ViewHolder subclass. The view holder pattern is now an integral part of this new way of doing adapter views. Your ViewHolder will set up all the child views for your view.
Then in your RecyclerView.Adapter subclass, override onCreateViewHolder() and onBindViewHolder(). In onCreateViewHolder() you inflate your view and construct the ViewHolder. In onBindViewHolder(), you use position to get the adapter data and set up the child views using the ViewHolder. So RecyclerView technically recycles ViewHolders that contain Views.
Once you make those changes to your adapter, you should be all set.
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