android自定义adapter之简单写法

来源：互联网发布：杭州淘宝电商大学编辑：程序博客网时间：2024/05/30 23:52

自定义adapter比较常用，很多人还在使用extends BaseAdapter，然后写一大堆重复的代码，这里是提供一个封装的工具类，把重复的代码都省略掉，让adapter变的简洁一些。

给控件设置adapter的调用代码大概是这样

mGridView.setAdapter(new CommonAdapter<GridBean>(mContext, list, R.layout.item_main_shouye_grid) {            @Override            public void convert(ViewHolder helper, GridBean item) {                helper.setText(R.id.tv_item, item.name);                helper.setImageResource(R.id.iv_item, item.icon);                ImageView imageView = helper.getView(R.id.image);                //DO your buisness with imageview            }        });

指明该adapter填充的数据类型，context，数据集data，和单项的布局文件，然后就是给各控件set值了。这样写adapter就比较简洁了。

CommonAdapter代码

package com.ab.hongyang;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import java.util.List;/** * Created by wuwf on 2015-04-07. */public abstract class CommonAdapter<T> extends BaseAdapter {    protected LayoutInflater mInflater;    protected Context mContext;    protected List<T> mDatas;    protected final int mItemLayoutId;    public CommonAdapter(Context context, List<T> mDatas, int itemLayoutId) {        mInflater = LayoutInflater.from(context);        this.mContext = context;        this.mDatas = mDatas;        this.mItemLayoutId = itemLayoutId;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        final ViewHolder viewHolder = getViewHolder(position, convertView,                parent);        convert(viewHolder, getItem(position));        return viewHolder.getConvertView();    }    public abstract void convert(ViewHolder helper, T item);    private ViewHolder getViewHolder(int position, View convertView,                                     ViewGroup parent) {        return ViewHolder.get(mContext, convertView, parent, mItemLayoutId,                position);    }    @Override    public int getCount() {        return mDatas.size();    }    @Override    public T getItem(int position) {        return mDatas.get(position);    }    @Override    public long getItemId(int position) {        return position;    }}

ViewHolder.java

package com.ab.hongyang;import android.content.Context;import android.graphics.Bitmap;import android.util.SparseArray;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ImageView;import android.widget.TextView;import com.ab.R;import com.ab.hongyang.imageloader.ImageLoader;public class ViewHolder {    private final SparseArray<View> mViews;    private int mPosition;    private View mConvertView;    private Context mContext;    private ViewHolder(Context context, ViewGroup parent, int layoutId,                       int position) {        mContext = context;        this.mPosition = position;        this.mViews = new SparseArray<View>();        mConvertView = LayoutInflater.from(context).inflate(layoutId, parent,                false);        //setTag        mConvertView.setTag(this);    }    /**     * 拿到一个ViewHolder对象     *     * @param context     * @param convertView     * @param parent     * @param layoutId     * @param position     * @return     */    public static ViewHolder get(Context context, View convertView,                                 ViewGroup parent, int layoutId, int position) {        if (convertView == null) {            return new ViewHolder(context, parent, layoutId, position);        }        return (ViewHolder) convertView.getTag();    }    /**     * 通过控件的Id获取对于的控件，如果没有则加入views     *     * @param viewId     * @return     */    public <T extends View> T getView(int viewId) {        View view = mViews.get(viewId);        if (view == null) {            view = mConvertView.findViewById(viewId);            mViews.put(viewId, view);        }        return (T) view;    }    public View getConvertView() {        return mConvertView;    }    /**     * 为TextView设置字符串     *     * @param viewId     * @param text     * @return     */    public ViewHolder setText(int viewId, String text) {        TextView view = getView(viewId);        view.setText(text);        return this;    }    /**     * 为ImageView设置图片     *     * @param viewId     * @param drawableId     * @return     */    public ViewHolder setImageResource(int viewId, int drawableId) {        ImageView view = getView(viewId);        view.setImageResource(drawableId);        return this;    }    /**     * 为ImageView设置图片     *     * @param viewId     * @return     */    public ViewHolder setImageBitmap(int viewId, Bitmap bm) {        ImageView view = getView(viewId);        view.setImageBitmap(bm);        return this;    }    /**     * 为ImageView设置图片     *     * @param viewId     * @param url     * @param url    是否是网络图片     * @return     */    public ViewHolder setImageByUrl(int viewId, String url, boolean isNet) {//        AbImageLoader.getInstance(mContext).display((ImageView) getView(viewId), url);        ImageView imageview = getView(viewId);        imageview.setImageResource(R.drawable.pictures_no);        ImageLoader.getInstance(3, ImageLoader.Type.LIFO).loadImage(url, imageview                , isNet);        return this;    }    public int getPosition() {        return mPosition;    }}

这个类提供了一些给textview和imageview填充值的方法，setImageByUrl是展示网络图片的，这个方法里替换为你自己的加载图片框架即可。推荐使用glide。

viewholder是来自于csdn的hongyang，http://blog.csdn.net/lmj623565791/article/list/1

相信CommonAdapter会给自定义adapter带来极大的方便

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