Recycler View

뷰를 재활용하면서 무한으로 리스트 뷰를 생성할 수 있는 커스텀적인 리스트 뷰

 

null != arraylistMusic이라는 조건식이 참(true)이라면 ?뒤에 이어지는 첫 번째 arralistMusic.size()를 수행하게 되고 반대로 거짓(false)이라면 0을 반환

 

.java 파일 만드는 법

좌측 app 폴더에 java 파일 클릭

com.example.recyclerview 폴더 우클릭

new > Java Class

 

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activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbarFadeDuration="0"
        android:scrollbarSize="5dp"
        android:scrollbarThumbVertical="@android:color/darker_gray"
        android:scrollbars="vertical"
        android:layout_weight="1">

    </androidx.recyclerview.widget.RecyclerView>

    <Button
        android:id="@+id/btn_add"
        android:layout_weight="8"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="추가"/>

</LinearLayout>

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item_list.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="wrap_content">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/iv_profile"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher"/>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center_vertical"
            android:orientation="vertical">

            <TextView
                android:id="@+id/tv_name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="khon"/>

            <TextView
                android:id="@+id/tv_content"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="리사이클러뷰"/>

        </LinearLayout>
    </LinearLayout>

</LinearLayout>

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MainData.java

package com.example.recyclerview;

public class MainData {

    private int iv_profile;
    private String tv_name;
    private String tv_content;


    // alt + ins 키 constructor
    public MainData(int iv_profile, String tv_name, String tv_content) {
        this.iv_profile = iv_profile;
        this.tv_name = tv_name;
        this.tv_content = tv_content;
    }

    // alt + ins 키 Getter and Setter
    public int getIv_profile() {
        return iv_profile;
    }

    public void setIv_profile(int iv_profile) {
        this.iv_profile = iv_profile;
    }

    public String getTv_name() {
        return tv_name;
    }

    public void setTv_name(String tv_name) {
        this.tv_name = tv_name;
    }

    public String getTv_content() {
        return tv_content;
    }

    public void setTv_content(String tv_content) {
        this.tv_content = tv_content;
    }
}

-------------------------------------------------

 

 

MainAdapter.java

package com.example.recyclerview;

import android.view.LayoutInflater;
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;

public class MainAdapter extends RecyclerView.Adapter<MainAdapter.CusteomViewHolder> {

    private ArrayList<MainData> arrayList;

    // alt + ins 키 comstructor
    public MainAdapter(ArrayList<MainData> arrayList) {
        this.arrayList = arrayList;
    }

    @NonNull
    @Override
    public MainAdapter.CusteomViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list,parent,false);
        CusteomViewHolder holder = new CusteomViewHolder(view);

        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull final MainAdapter.CusteomViewHolder holder, int position) {
        holder.iv_prifile.setImageResource(arrayList.get(position).getIv_profile());
        holder.tv_name.setText(arrayList.get(position).getTv_name());
        holder.tv_content.setText(arrayList.get(position).getTv_content());

        holder.itemView.setTag(position);
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String curName = holder.tv_name.getText().toString();
                Toast.makeText(view.getContext(), curName, Toast.LENGTH_SHORT).show();
            }
        });

        holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                remove(holder.getAdapterPosition());

                return true;
            }
        });

    }

    @Override
    public int getItemCount() {
        return (null != arrayList ? arrayList.size() : 0);
    }

    public void remove(int position) {
        try {
            arrayList.remove(position);
            notifyItemRemoved(position);
        }catch (IndexOutOfBoundsException ex) {
            ex.printStackTrace(); // 예외 상황이 벌어졌을때 강제 실행
        }
    }

    public class CusteomViewHolder extends RecyclerView.ViewHolder {

        protected ImageView iv_prifile;
        protected TextView tv_name;
        protected TextView tv_content;

        public CusteomViewHolder(@NonNull View itemView) {
            super(itemView);
            this.iv_prifile = (ImageView) itemView.findViewById(R.id.iv_profile);
            this.tv_name = (TextView) itemView.findViewById(R.id.tv_name);
            this.tv_content = (TextView) itemView.findViewById(R.id.tv_content);
        }
    }
}

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build.gradle (:app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.1"

    defaultConfig {
        applicationId "com.example.recyclerview"
        minSdkVersion 15
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.recyclerview:recyclerview:1.1.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

}

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MainActivity.java

package com.example.recyclerview;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private ArrayList<MainData> arrayList;
    private MainAdapter mainAdapter;
    private RecyclerView recyclerView;
    private LinearLayoutManager linearLayoutManger;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        recyclerView = (RecyclerView)findViewById(R.id.rv);
        linearLayoutManger = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManger);

        arrayList = new ArrayList<>();

        mainAdapter = new MainAdapter(arrayList);
        recyclerView.setAdapter(mainAdapter);

        Button btn_add = (Button)findViewById(R.id.btn_add);
        btn_add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                MainData mainData = new MainData(R.mipmap.ic_launcher,"khon", "리사이클러뷰");
                arrayList.add(mainData);
                mainAdapter.notifyDataSetChanged();
            }
        });
    }
}