以前一直是用傳統的方式,需要寫很多findviewById(),重複代碼很多,最近空閒,自己寫個小項目練習,也使用了一下DataBinding,發現確實簡單很多,現在把過程和經驗和大家分享一下。
這是需求界面,我們可以用listview去完成,但是現在介紹的是DataBinding結合RecyclerView去加載。
1.首先,我們需要在buld.gradle中添加依賴,
2.在佈局中使用
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data class="com.mymusic.musicplayer.SalesRankData"> //這個是系統自動創建的"隱形"類,我們指定了類名爲SalesRankData
<variable
name="salesBean" //實體類變量名
type="com.mymusic.musicplayer.bean.RankingBean.SalesBean.BooksBeanDes" /> //這裏是我們需要綁定的實體類
</data>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="10dp">
<TextView
android:id="@+id/tv_item_salesrank_number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginRight="10sp"
android:text="01"
android:textColor="@color/main_buttomtext_yellow"
android:textSize="14sp" />
<ImageView
android:id="@+id/iv_item_salesrank"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginRight="10dp"
android:layout_toRightOf="@+id/tv_item_salesrank_number"
app:imgurl="@{salesBean.book.cover}" /> //圖片加載,使用app:imgurl,imgurl是自己定義的變量
<TextView
android:id="@+id/tv_item_salesrank_title"
style="@style/tv_standard_12sp"
android:layout_alignTop="@+id/iv_item_salesrank"
android:layout_toRightOf="@+id/iv_item_salesrank"
android:text="@{salesBean.book.title}" /> //綁定實體類裏面的值,需要哪一個值就指定到哪層
<TextView
android:id="@+id/tv_item_salesrank_description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/iv_item_salesrank"
android:layout_toRightOf="@+id/iv_item_salesrank"
android:text="@{salesBean.book.author.title+@string/colon+salesBean.book.author.name+@string/space+salesBean.book.recorder.title+@string/colon+salesBean.book.recorder.name}"
android:textColor="@color/gray_hotlists"
android:textSize="10sp" />
<View
android:layout_width="match_parent"
android:layout_height="0.2dp"
android:layout_below="@+id/tv_item_salesrank_description"
android:layout_marginTop="10dp"
android:background="@color/view" />
</RelativeLayout>
</layout>
實體類代碼太多,我直接貼hijson的截圖,
3.Activity裏面做好準備操作
public class SalesRankActivity extends BaseActivity implements IBookRankView {
private SalesData salesData;//SalesData就是databinding自動生成的類,我們自己在佈局中改成了此類名
private LinearLayoutManager linearLayoutManager; //佈局管理器
private List<RankingBean.SalesBean.BooksBeanDes> salesBeen;//這是要加載的List,也就是上面截圖裏最外層的集合
private SalesRankAdapter salesRankAdapter;
private BookRankPersenter bookRankPersenter = new BookRankPersenter(this);
@Override
void initdatabinding() {
salesData = DataBindingUtil.setContentView(this, R.layout.activity_salesrank);//載入佈局
}
@Override
public void initData() {
super.initData();
linearLayoutManager = new LinearLayoutManager(this);
salesData.rvSalesRank.setLayoutManager(linearLayoutManager);//recyclerview加載佈局管理器,不設置方向的話,默認是垂直
salesBeen = new ArrayList<>();
salesRankAdapter = new SalesRankAdapter(salesBeen);
salesData.rvSalesRank.setAdapter(salesRankAdapter);
bookRankPersenter.getData();
}
@Override
public void onClick(View view) {
}
@Override
public void setOnclick() {
}
@Override
public void getAllData(RankingBean rankingBean) {
salesBeen.clear();
List<RankingBean.SalesBean.BooksBeanDes> books = rankingBean.getSales().getBooks();
salesBeen.addAll(books);
salesRankAdapter.notifyDataSetChanged();//這裏設置list,adapter刷新和以前的方式都一樣
}
}
4.Adapter裏填充數據
public class SalesRankAdapter extends BaseDatabindingAdapter<RankingBean.SalesBean.BooksBeanDes, SalesRankAdapter.ViewHolder> {
public SalesRankAdapter(List<RankingBean.SalesBean.BooksBeanDes> data) {
super(data);
}
@Override
Class<SalesRankAdapter.ViewHolder> vhClass() {
return ViewHolder.class;
}
@Override
int initLayoutId() {
return R.layout.item_salesrank;//item佈局
}
@Override
public void onBindViewHolder(SalesRankAdapter.ViewHolder holder, int position) {
RankingBean.SalesBean.BooksBeanDes booksBeanX = data.get(position);
holder.databinding.setSalesBean(booksBeanX);//設置好需要的Bean值即可,控件加載數據我們在佈局中已經寫過了
if (position > 8) {//這裏是前面的序號,因爲不是從Bean中得到的,所以還是自己寫
holder.databinding.tvItemSalesrankNumber.setText(String.valueOf(position + 1));
} else {
holder.databinding.tvItemSalesrankNumber.setText("0" + (position + 1));
}
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(View itemView) {
super(itemView);
}
public SalesRankData databinding;
public ViewHolder(ViewDataBinding itemView) {
super(itemView.getRoot());
this.databinding = (SalesRankData) itemView;//把ViewDataBinding強轉成我們定義的類
}
}
}
我這裏寫了BaseAdapter,所以和平常的風格有些不一樣,但邏輯都是一樣的,我把BaseAdpater類貼出來供大家參考
public abstract class BaseAdapter<T, VH extends RecyclerView.ViewHolder> extends RecyclerView.Adapter<VH> {
public List<T> data;
public BaseAdapter(List<T> data) {
this.data = data;
}
@Override
public VH onCreateViewHolder(ViewGroup parent, int viewType) {
Class<VH> vhClass = vhClass();
VH tTH = null;
Constructor c1 = null;
try {
c1 = vhClass.getDeclaredConstructor(new Class[]{View.class});
c1.setAccessible(true);
View inflate = View.inflate(parent.getContext(), initLayoutId(), null);
tTH = (VH) c1.newInstance(inflate);
} catch (Exception e) {
System.out.println("反射泛型失敗");
}
return tTH;
}
abstract Class<VH> vhClass();
abstract int initLayoutId();
@Override
public int getItemCount() {
if (data == null)
return 0;
return data.size();
}
}
寫完adapter效果就能出來了,這裏說一下圖片加載,我們需要自己去寫@BindingAdapter
public class ImagBindingUtils {
@BindingAdapter("imgurl")
public static void bindingImage(ImageView imageView, String url) {
Glide.with(imageView.getContext()).load(url).into(imageView);//用glide加載圖片,imgurl在上面的佈局裏面有使用過
}
}
最後注意一些小細節,比如文字中需要空格我們在佈局中無法直接使用“ ”+,上面有個text值是 @{salesBean.book.author.title+@string/colon+salesBean.book.author.name+@string/space+salesBean.book.recorder.title+@string/colon+salesBean.book.recorder.name}
這裏的@string/colon和@string/space分別定義的是冒號和空格,在values的strings裏面使用
,其中 是空格符
這篇博客未寫到聯網請求代碼,如不懂的話,可以先去看看我寫的"Retrofit2.0的簡單實用",http://blog.csdn.net/xkyh941/article/details/78562340,如有問題,可以留言~