증상 : adapter.addItem으로 추가한 이미지만 화면에 정상적으로 보이지 않습니다. (텍스트는 정상표시는데 이미지는 빈 공간으로 보여요)

singer_item.xml에서 ImageView태그 안에 src만 적용한 상태에서는 이미지가 잘 보입니다.

강좌를 여러번 봐도 틀린 부분이 잘 안보이는데 몇 일째 해결이 안되네요. 도와주세요!

아래 코드 첨부할게요.

<<MainActivity.java 파일>>

package org.techtown.list;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    SingerAdapter adapter;

    EditText editText;
    EditText editText2;

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

        editText = (EditText) findViewById(R.id.editText);
        editText2 = (EditText) findViewById(R.id.editText2);

        ListView listView = (ListView) findViewById(R.id.listView);

        adapter = new SingerAdapter();
        for(int i=0; i<10000; i++) {
            adapter.addItem(new SingerItem("소녀시대" + i, "010-1000-" + i, R.drawable.kakao));
        }

        listView.setAdapter(adapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                SingerItem item = (SingerItem) adapter.getItem(position);
                Toast.makeText(getApplicationContext(), "선택 : " + item.getName(), Toast.LENGTH_LONG).show();

            }
        });

        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String name = editText.getText().toString();
                String mobile = editText2.getText().toString();

                adapter.addItem(new SingerItem(name, mobile, R.drawable.kakao));
                adapter.notifyDataSetChanged();
            }
        });

    }

    class SingerAdapter extends BaseAdapter {
        ArrayList<SingerItem> items = new ArrayList<SingerItem>();

        @Override
        public int getCount() {
            return items.size();
        }

        public void addItem(SingerItem item) {
            items.add(item);
        }

        @Override
        public Object getItem(int position) {
            return items.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            SingerItemView view = null;
            if( convertView == null) {
                view = new SingerItemView(getApplicationContext());
            } else {
                view = (SingerItemView) convertView;
            }


            SingerItem item = items.get(position);
            view.setName(item.getName());
            view.setMobile(item.getMobile());
            view.setImage(item.getResId());

            return view;
        }
    }


}

<<singer_item.xml 파일>>

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

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:src="@mipmap/ic_launcher" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginLeft="10dp">

        <TextView
            android:id="@+id/textView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="이름"
            android:textSize="30dp"
            android:textColor="@color/colorPrimaryDark"/>

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="8dp"
            android:text="전화번호"
            android:textSize="24dp"
            android:textColor="@android:color/holo_orange_dark"/>


    </LinearLayout>

</LinearLayout>

<SingerItemView.java 파일>>

package org.techtown.list;

import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class SingerItemView extends LinearLayout {

    TextView textView;
    TextView textView2;
    ImageView imageView;

    public SingerItemView(Context context) {
        super(context);

        init(context);
    }

    public SingerItemView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);

        init(context);
    }

    private void init(Context context) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.singer_item, this, true);

        textView = (TextView) findViewById(R.id.textView);
        textView2 = (TextView) findViewById(R.id.textView2);
        imageView = (ImageView) findViewById(R.id.imageView);

    }

    public void setName(String name) {
        textView.setText(name);
    }

    public void setMobile(String mobile) {
        textView2.setText(mobile);
    }

    public void setImage(int resId) {
        imageView.setImageResource(resId);
    }
}

<SingerItem.java 파일>>

package org.techtown.list;

public class SingerItem {

    String name;
    String mobile;
    int resId;

    public SingerItem(String name, String mobile, int resId) {
        this.name = name;
        this.mobile = mobile;
        this.resId = resId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getMobile() {
        return mobile;
    }

    public void setMobile(String mobile) {
        this.mobile = mobile;
    }

    public int getResId() {
        return resId;
    }

    public void setResId(int resId) {
        this.resId = resId;
    }

}

리스트뷰 코드는 서로 연관되어 있어 모두 올려봅니다. 부탁드려요.