Android RecyclerView 簡單使用

使用

1、建立2個布局檔案

一個放有RecyclerView元件

一個有是實作的樣式xml

activity_mian.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
    android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recycler_test"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginTop="5dp"
    />
    
</androidx.constraintlayout.widget.ConstraintLayout>
           

條目布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="110dp"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >

<ImageView
    android:id="@+id/img_picture"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_rubbish01"
    android:layout_gravity="center_horizontal"
    />
    <TextView
        android:id="@+id/tv_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="題目"
        android:textSize="20dp"
        />
</LinearLayout>
           

2、建立bean類用來儲存myrecycler.xml中的元件的資料，建立get和set方法

infobean.java

package com.example.xianyu;
public class infoBean {
    private int picture;
    private String title;
  infoBean(int picture,String title){
      this.picture = picture;
      this.title = title;
  }

    public int getPicture() {
        return picture;
    }

    public void setPicture(int picture) {
        this.picture = picture;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

}
           

3、建立擴充卡，并設定item的點選事件

要點:

(1)、擴充卡繼承自RecyclerView.Adapter

(2)、擴充卡裡的泛型需自定義，并且繼承自RecyclerView.ViewHolder，主要是執行個體化元件

(3)、onBindViewHolder方法，利用傳進來的ArrayList，進行綁定資料

(4)、執行順序:

onCreateViewHolder(找到布局)—>MyViewHolder(找到元件) —>onBindViewHolder(綁定資料)

myadapter.java

package com.example.xianyu;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;


public class myadapter extends RecyclerView.Adapter<myadapter.MyViewHolder>{
    private final Context context;
    List<infoBean> data = new ArrayList<infoBean>();
/*
自定義的構造方法 ，傳入上下文對象context 和data資料
 */
myadapter(Context context, List<infoBean> data){
    this.context = context;
    this.data = data;
}
/*
getview
 */
    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = View.inflate(context,R.layout.myrecycler,null);     
        return new MyViewHolder(view);
    }
/*
綁定資料
 */
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        
    infoBean bean = data.get(position);
       holder.picture.setImageResource(bean.getPicture());
        holder.title.setText(bean.getTitle());

        //設定item的點選事件
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(context,bean.getTitle(), Toast.LENGTH_LONG).show();
            }
        });
    }

    /*
    *得到總條數，傳回data.size() 就可以了
    */
    @Override
    public int getItemCount() {
        return data.size();
    }

    /*
    也是getview
     */
    class MyViewHolder extends RecyclerView.ViewHolder{

          private ImageView picture;
          private TextView title;
           public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            picture = itemView.findViewById(R.id.img_picture);
            title = itemView.findViewById(R.id.tv_title);
        }
    }
}
           

4、在主Activity設定RecyclerView

homeActivity.java

package com.example.xianyu;
import android.app.Activity;
import android.os.Bundle;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

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

public class homeActivity extends Activity {
  private RecyclerView mrecycler;
    List<infoBean> data = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mian);
        initDate();
mrecycler = findViewById(R.id.recycler_test);
//設定擴充卡
mrecycler.setAdapter(new myadapter(homeActivity.this,data));
//設定樣式 ,有如下:
// LinearLayoutManager(Context context, @RecyclerView.Orientation int orientation,boolean reverseLayout)
//GridLayoutManager(Context context, int spanCount)
//StaggeredGridLayoutManager(int spanCount, int orientation)
mrecycler.setLayoutManager(new GridLayoutManager(homeActivity.this,3));
    }
//資料
    private void initDate() {
        data.add(new infoBean(R.drawable.ic_rubbish02,"幹"));        
        data.add(new infoBean(R.drawable.ic_rubbish03,"濕"));
         data.add(new infoBean(R.drawable.ic_rubbish01,"有害"));
        data.add(new infoBean(R.drawable.ic_rubbish04,"其他"));
        data.add(new infoBean(R.drawable.ic_rubbish05,"回收"));
        data.add(new infoBean(R.drawable.ic_rubbish06,"廚餘"));

    }
}