การใช้ ViewHolder ร่วมกับ Custom ListView

layout/custom_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:columnCount="3"
    android:descendantFocusability="blocksDescendants"
    android:rowCount="2">

    <ImageView
        android:id="@+id/imageView"
        android:layout_margin="10dp"
        android:layout_marginLeft="5dp"
        android:layout_rowSpan="2"
        android:src="@mipmap/ic_launcher" />

    <TextView
        android:id="@+id/textViewTitle"
        android:layout_columnWeight="1"
        android:layout_marginBottom="3dp"
        android:layout_marginTop="5dp"
        android:text="Title"
        android:textColor="#00b"
        android:textSize="18sp"
        android:textStyle="bold" />

    <CheckBox
        android:id="@+id/checkbox"
        android:layout_marginTop="15dp"
        android:layout_rowSpan="2" />

    <TextView
        android:id="@+id/textViewContent"
        android:layout_columnWeight="1"
        android:layout_marginBottom="5dp"
        android:text="Content"
        android:textSize="16sp" />

</GridLayout>

<?xml version="1.0" encoding="utf-8"?>

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:columnCount="3"

android:descendantFocusability="blocksDescendants"

android:rowCount="2">

<ImageView

android:id="@+id/imageView"

android:layout_margin="10dp"

android:layout_marginLeft="5dp"

android:layout_rowSpan="2"

android:src="@mipmap/ic_launcher" />

<TextView

android:id="@+id/textViewTitle"

android:layout_columnWeight="1"

android:layout_marginBottom="3dp"

android:layout_marginTop="5dp"

android:text="Title"

android:textColor="#00b"

android:textSize="18sp"

android:textStyle="bold" />

<CheckBox

android:id="@+id/checkbox"

android:layout_marginTop="15dp"

android:layout_rowSpan="2" />

<TextView

android:id="@+id/textViewContent"

android:layout_columnWeight="1"

android:layout_marginBottom="5dp"

android:text="Content"

android:textSize="16sp" />

</GridLayout>

ViewHolder.java

package com.phaisarn.myapplication;

import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class ViewHolder {
    public ImageView imageView;
    public TextView textViewTitle;
    public TextView textViewContent;

    public ViewHolder(View convertView) {
        imageView = (ImageView)convertView.findViewById(R.id.imageView);
        textViewTitle = (TextView)convertView.findViewById(R.id.textViewTitle);
        textViewContent = (TextView)convertView.findViewById(R.id.textViewContent);
    }
}

package com.phaisarn.myapplication;

import android.view.View;

import android.widget.ImageView;

import android.widget.TextView;

public class ViewHolder {

public ImageView imageView;

public TextView textViewTitle;

public TextView textViewContent;

public ViewHolder(View convertView) {

imageView = (ImageView)convertView.findViewById(R.id.imageView);

textViewTitle = (TextView)convertView.findViewById(R.id.textViewTitle);

textViewContent = (TextView)convertView.findViewById(R.id.textViewContent);

}

CustomAdapter.java

package com.phaisarn.myapplication;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import java.util.ArrayList;

public class CustomAdapter extends ArrayAdapter {
    private Context mContext;
    private ArrayList<CustomItem> mItems;
    private ViewHolder mHolder;

    public CustomAdapter(Context context, ArrayList<CustomItem> items) {
        super(context, 0, items);
        mContext = context;
        mItems = items;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if(convertView == null) {
            LayoutInflater inflater = LayoutInflater.from(mContext);
            convertView = inflater.inflate(R.layout.custom_layout, parent, false);
            mHolder = new ViewHolder(convertView);
            convertView.setTag(mHolder);
        } else {
            mHolder = (ViewHolder)convertView.getTag();
        }

        CustomItem item = mItems.get(position);
        mHolder.imageView.setImageResource(item.imgId);
        mHolder.textViewTitle.setText(item.title);
        mHolder.textViewContent.setText(item.content);

        return convertView;
    }
}

package com.phaisarn.myapplication;

import android.content.Context;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import java.util.ArrayList;

public class CustomAdapter extends ArrayAdapter {

private Context mContext;

private ArrayList<CustomItem> mItems;

private ViewHolder mHolder;

public CustomAdapter(Context context, ArrayList<CustomItem> items) {

super(context, 0, items);

mContext = context;

mItems = items;

}

@Override

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

if(convertView == null) {

LayoutInflater inflater = LayoutInflater.from(mContext);

convertView = inflater.inflate(R.layout.custom_layout, parent, false);

mHolder = new ViewHolder(convertView);

convertView.setTag(mHolder);

} else {

mHolder = (ViewHolder)convertView.getTag();

}

CustomItem item = mItems.get(position);

mHolder.imageView.setImageResource(item.imgId);

mHolder.textViewTitle.setText(item.title);

mHolder.textViewContent.setText(item.content);

return convertView;

}

CustomItem.java

package com.phaisarn.myapplication;

class CustomItem {
    public int imgId;
    public String title;
    public String content;

    public CustomItem(int imgId, String title, String content) {
        this.imgId = imgId;
        this.title = title;
        this.content = content;
    }
}

package com.phaisarn.myapplication;

class CustomItem {

public int imgId;

public String title;

public String content;

public CustomItem(int imgId, String title, String content) {

this.imgId = imgId;

this.title = title;

this.content = content;

}

content_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:id="@+id/content_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

<?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:id="@+id/content_main"

android:layout_width="match_parent"

android:layout_height="match_parent"

app:layout_behavior="@string/appbar_scrolling_view_behavior"

tools:context=".MainActivity"

tools:showIn="@layout/activity_main">

<ListView

android:id="@+id/listView"

android:layout_width="match_parent"

android:layout_height="match_parent" />

</LinearLayout>

MainActivity.java

package com.phaisarn.myapplication;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
            /*
            FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
            fab.setOnClickListener(new View.OnClickListener() {
                  @Override
                  public void onClick(View view) {
                        Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                                .setAction("Action", null).show();
                  }
            });
            */
        ArrayList<CustomItem> itemArray = new ArrayList<>();
        itemArray.addAll(Arrays.asList(
                new CustomItem(R.drawable.ic_1, "One", "รายการที่ 1"),
                new CustomItem(R.drawable.ic_2, "Two", "รายการที่ 2"),
                new CustomItem(R.drawable.ic_3, "Three", "รายการที่ 3"),
                new CustomItem(R.drawable.ic_4, "Four", "รายการที่ 4"),
                new CustomItem(R.drawable.ic_5, "Five", "รายการที่ 5")));

        CustomAdapter adapter =
                new CustomAdapter(getBaseContext(), itemArray);

        ListView listView = (ListView) findViewById(R.id.listView);
        listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if(id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

package com.phaisarn.myapplication;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.support.v7.widget.Toolbar;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.ListView;

import java.util.ArrayList;

import java.util.Arrays;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);

fab.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)

.setAction("Action", null).show();

}

});

ArrayList<CustomItem> itemArray = new ArrayList<>();

itemArray.addAll(Arrays.asList(

new CustomItem(R.drawable.ic_1, "One", "รายการที่ 1"),

new CustomItem(R.drawable.ic_2, "Two", "รายการที่ 2"),

new CustomItem(R.drawable.ic_3, "Three", "รายการที่ 3"),

new CustomItem(R.drawable.ic_4, "Four", "รายการที่ 4"),

new CustomItem(R.drawable.ic_5, "Five", "รายการที่ 5")));

CustomAdapter adapter =

new CustomAdapter(getBaseContext(), itemArray);

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

listView.setAdapter(adapter);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.menu_main, menu);

return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// Handle action bar item clicks here. The action bar will

// automatically handle clicks on the Home/Up button, so long

// as you specify a parent activity in AndroidManifest.xml.

int id = item.getItemId();

//noinspection SimplifiableIfStatement

if(id == R.id.action_settings) {

return true;

}

return super.onOptionsItemSelected(item);

}

รูปที่ใช้

Phaisarn Sutheebanjard

blog.phaisarn.com

การใช้ ViewHolder ร่วมกับ Custom ListView