首先来看看效果吧:
本实例来自于慕课网的视屏http://www.imooc.com/video/13046,实现步骤可以自己去观看视屏,这里只记录了下实现的代码。
(1) 在项目的build.gradle文件中添加下面的依赖
compile 'com.android.support:recyclerview-v7:25.0.0'
(2) 也可以在下图中自动进行依赖,选择RecycleView即可。
直接代码传送门
MainActivity
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private MyAdapter mMyAdapter;
private int colors[] = {android.R.color.holo_blue_bright,android.R.color.black,android.R.color.holo_red_dark};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
}
private void initView() {
mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerView);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL,
false));
mMyAdapter = new MyAdapter(this);
mRecyclerView.setAdapter(mMyAdapter);
}
private void initData() {
List list= new ArrayList<>();
for (int i = 0; i < 20; i++) {
Person p = new Person();
int type = (int) (Math.random()*3+1);
p.type = type;
p.content="content"+1;
p.avaterColor = colors[type-1];
p.name = "name"+i;
list.add(p);
}
mMyAdapter.addList(list);
mMyAdapter.notifyDataSetChanged();
}
}
bean对象Person类
/**
* Created by 24540 on 2017/3/13.
*/
public class Person {
public static final int TYPE_ONE = 1;
public static final int TYPE_TWO = 2;
public static final int TYPE_THREE = 3;
protected int type;
protected int avaterColor;
protected int contentColor;
protected String name;
protected String content;
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getContentColor() {
return contentColor;
}
public void setContentColor(int contentColor) {
this.contentColor = contentColor;
}
public int getAvaterColor() {
return avaterColor;
}
public void setAvaterColor(int avaterColor) {
this.avaterColor = avaterColor;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
public static int getTypeThree() {
return TYPE_THREE;
}
public static int getTypeTwo() {
return TYPE_TWO;
}
public static int getTypeOne() {
return TYPE_ONE;
}
}
RecycleView的适配器
public class MyAdapter extends RecyclerView.Adapter {
private LayoutInflater mLayoutInflater;
private List mList = new ArrayList<>();
private Context mContext;
public MyAdapter(Context mContext) {
this.mContext = mContext;
mLayoutInflater = LayoutInflater.from(mContext);
}
//使用此方法从获取数据
public void addList(List list){
mList.addAll(list);
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//根据不同的viewType,创建并返回影响的ViewHolder
switch (viewType){
case Person.TYPE_ONE:
return new TypeOneHolder(mLayoutInflater.inflate(R.layout.item_type_one,parent,false));
case Person.TYPE_TWO:
return new TypeTwoHolder(mLayoutInflater.inflate(R.layout.item_type_two,parent,false));
case Person.TYPE_THREE:
return new TypeThreeHolder(mLayoutInflater.inflate(R.layout.item_type_three,parent,false));
}
return null;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
//抽象出TypeAbstartViewHolder,所以在进行绑定的时候可以直接调用
((TypeAbstartViewHolder)holder).bindHolder(mList.get(position));
}
@Override
public int getItemViewType(int position) {
return mList.get(position).getType();
}
@Override
public int getItemCount() {
return mList.size();
}
}
关键的一点,TypeAbstartViewHolder 抽象出bindHolder方法,优雅实现加载不同item布局,代码如下:
public abstract class TypeAbstartViewHolder extends RecyclerView.ViewHolder {
public TypeAbstartViewHolder(View itemView) {
super(itemView);
}
public abstract void bindHolder(Person person);
}
继承自上面抽象的方法,实现加载不同item布局TypeOneHolder:
public class TypeOneHolder extends TypeAbstartViewHolder {
private ImageView avater;
private TextView name;
public TypeOneHolder(View itemView) {
super(itemView);
avater = (ImageView) itemView.findViewById(R.id.avater);
name = (TextView) itemView.findViewById(R.id.name);
}
//为ViewHolder绑定数据
@Override
public void bindHolder(Person person) {
avater.setBackgroundResource(person.getAvaterColor());
name.setText(person.getName());
}
}
TypeTwoHolde代码如下:
public class TypeTwoHolder extends TypeAbstartViewHolder {
private ImageView avater;
private TextView name;
private TextView content;
public TypeTwoHolder(View itemView) {
super(itemView);
avater = (ImageView) itemView.findViewById(R.id.avater);
name = (TextView) itemView.findViewById(R.id.name);
content = (TextView) itemView.findViewById(R.id.content);
}
//为ViewHolder绑定数据
@Override
public void bindHolder(Person person) {
avater.setBackgroundResource(person.getAvaterColor());
name.setText(person.getName());
content.setText(person.getContent());
}
}
TypeThreeHolder的代码如下:
public class TypeThreeHolder extends TypeAbstartViewHolder {
private ImageView avater;
private TextView name;
private TextView content;
private ImageView iv;
public TypeThreeHolder(View itemView) {
super(itemView);
avater = (ImageView) itemView.findViewById(R.id.avater);
name = (TextView) itemView.findViewById(R.id.name);
content = (TextView) itemView.findViewById(R.id.content);
iv = (ImageView) itemView.findViewById(R.id.content_color);
}
//为ViewHolder绑定数据
@Override
public void bindHolder(Person person) {
avater.setBackgroundResource(person.getAvaterColor());
name.setText(person.getName());
content.setText(person.getContent());
iv.setBackgroundResource(person.getAvaterColor());
}
}
xml文件代码部分:只放出了item_type_three部分的代码:
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private MyAdapter mMyAdapter;
private int colors[] = {android.R.color.holo_blue_bright, android.R.color.black, android.R.color.holo_red_dark};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
}
private void initView() {
mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerView);
//构造参数里面的2表示的是一行有两列
final GridLayoutManager manager = new GridLayoutManager(this, 2);
mRecyclerView.setLayoutManager(manager);
manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
int type = mRecyclerView.getAdapter().getItemViewType(position);
//若是TYPE_THREE,占用两列,否则占用一列
if (type == Person.TYPE_THREE) {
return manager.getSpanCount();
} else {
return 1;
}
}
});
mMyAdapter = new MyAdapter(this);
//给布局里的子view添加边距
mRecyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
GridLayoutManager.LayoutParams layoutParams = (GridLayoutManager.LayoutParams) view.getLayoutParams();
int spanSize = layoutParams.getSpanSize();
int spanIndex = layoutParams.getSpanIndex();
outRect.top = 20;
if (spanSize != manager.getSpanCount()) {
if (spanIndex == 0) {
outRect.right = 0;
} else {
outRect.right = 10;
}
}
}
});
mRecyclerView.setAdapter(mMyAdapter);
}
private void initData() {
List list = new ArrayList<>();
for (int i = 0; i < 20; i++) {
Person p = new Person();
int type = (int) (Math.random() * 3 + 1);
p.type = type;
p.content = "content" + 1;
p.avaterColor = colors[type - 1];
p.name = "name" + i;
list.add(p);
}
mMyAdapter.addList(list);
mMyAdapter.notifyDataSetChanged();
}
}
效果如图: