Question

我有GridView加载了大约15张图片，而不是那么多，但是当我测试它时，滚动速度非常慢，我无法弄明白为什么。

我从array.xml文件中获取所有图片。

array.xml

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

    <string-array name="chuck_ids">
        <item>@drawable/chuck_1</item>
        <item>@drawable/chuck_2</item>
        <item>@drawable/chuck_3</item>
        <item>@drawable/chuck_4</item>
        <item>@drawable/chuck_5</item>
        <item>@drawable/chuck_6</item>
        <item>@drawable/chuck_7</item>
        <item>@drawable/chuck_8</item>
        <item>@drawable/chuck_9</item>
        <item>@drawable/chuck_10</item>
        <item>@drawable/chuck_11</item>
        <item>@drawable/chuck_12</item>
        <item>@drawable/chuck_13</item>
        <item>@drawable/chuck_14</item>
    </string-array>
</resources>

这是我的代码：

import java.util.ArrayList;
import java.util.HashMap;

import android.app.Fragment;
import android.content.Intent;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;

import com.italiandevteam.chuck.adapter.GridViewAdapter;
import com.italiandevteam.chuck.model.ImageItem;

public class GalleriaPersonaggio extends Fragment{

    Integer personaggio = null;


    public GalleriaPersonaggio( int personaggio ){

        this.personaggio = personaggio;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        int id = getIdPersonaggio();

        View rootView = null;

        try {
                rootView = inflater.inflate(R.layout.gallery_grid, container, false);
            } 
        catch (InflateException e) {
        }

        final GridView gridView = (GridView) rootView.findViewById(R.id.gridView);
        GridViewAdapter customGridAdapter = new GridViewAdapter(getActivity(), R.layout.gallery_row, getData(personaggio));
        gridView.setAdapter(customGridAdapter);

        gridView.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
//              HashMap<String, Object> hm = gridView.getAdapter().getPosition(position);
//
//                 String imgPath = (String) hm.get("flag"); //get downloaded image path
//              Intent i = new Intent(getActivity(), MostraImmagine.class); //start new Intent to another Activity.
//              i.putExtra("ClickedImagePath", imgPath ); //put image link in intent.
//              startActivity(i);
            }

    });

        return rootView;
    }

    public int getIdPersonaggio(){
        return this.personaggio;
    }

    private ArrayList getData(int personaggio) {
        final ArrayList imageItems = new ArrayList();
        // retrieve String drawable array
        TypedArray imgs = null;

        switch( personaggio )
        {        
            case 1:{
                imgs = getResources().obtainTypedArray(R.array.chuck_ids);
                break;
            }
            case 2:{
                imgs = getResources().obtainTypedArray(R.array.sarah_ids);
                break;
            }
            case 3:{
                //To do
                break;
            }
            case 4:{
                //To do
                break;
            }
            case 5:{
                //To do
                break;
            }
            case 6:{
                //To do
                break;
            }
            case 7:{
                //To do
                break;
            }
            case 8:{
                //To do
                break;
            }
            default:{
                imgs = getResources().obtainTypedArray(R.array.chuck_ids);
            }

        }

        for (int i = 0; i < imgs.length(); i++) {
            Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(), imgs.getResourceId(i, -1));
            imageItems.add(new ImageItem(bitmap, "Image#" + i));
        }

        return imageItems;

    }
}

GridViewAdapter.java

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.italiandevteam.chuck.R;
import com.italiandevteam.chuck.model.ImageItem;


public class GridViewAdapter extends ArrayAdapter<ImageItem> {
    private Context context;
    private int layoutResourceId;
    private ArrayList<ImageItem> data = new ArrayList<ImageItem>();

    public GridViewAdapter(Context context, int layoutResourceId,
                    ArrayList<ImageItem> data) {
            super(context, layoutResourceId, data);
            this.layoutResourceId = layoutResourceId;
            this.context = context;
            this.data = data;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
            View row = convertView;
            ViewHolder holder = null;

            if (row == null) {
                    LayoutInflater inflater = ((Activity) context).getLayoutInflater();
                    row = inflater.inflate(layoutResourceId, parent, false);
                    holder = new ViewHolder();
                    holder.imageTitle = (TextView) row.findViewById(R.id.text);
                    holder.image = (ImageView) row.findViewById(R.id.image);
                    row.setTag(holder);
            } else {
                    holder = (ViewHolder) row.getTag();
            }

            ImageItem item = data.get(position);
            holder.imageTitle.setText(item.getTitle());
            holder.image.setImageBitmap(item.getImage());
            return row;
    }

    static class ViewHolder {
            TextView imageTitle;
            ImageView image;
    }
}

ImageItem.java

import android.graphics.Bitmap;


public class ImageItem {
    private Bitmap image;
    private String title;

    public ImageItem(Bitmap image, String title) {
        super();
        this.image = image;
        this.title = title;
    }

    public Bitmap getImage() {
        return image;
    }

    public void setImage(Bitmap image) {
        this.image = image;
    }

    public String getTitle() {
        return title;
    }

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

基本上我根据java文件中的开关中的drawable加载array ID资源。如何改进滚动？

Answer 1

请尝试Universal Image Downloader从服务器或SD卡加载图像。它就像魅力一样！

Answer 2

是的，你应该创建拇指并缓存内存。它肯定会解决你的问题。

这是android中缓存实现的链接。

http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html

Android - GridView和图像性能问题

2 个答案: