图片的三级缓存

于 2016-09-06 16:00:55 发布
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版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/zhoumin1223/article/details/52450825
版权


package com.example.image;

import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.graphics.Bitmap;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class MainActivity extends Activity {

    private ImageLoaderUtils utils;
    private GridView gv;
    private Handler handler=new Handler(){
        public void handleMessage(android.os.Message msg) {
            if(msg.what==0){
                Bitmap bitmap=(Bitmap) msg.obj;
                //设置给ImageView
                String tag=msg.getData().getString("tag");
                //根据标记去除ImageView
                ImageView imageView=(ImageView) gv.findViewWithTag(tag);
                if(imageView!=null&&bitmap!=null){
                    imageView.setImageBitmap(bitmap);
                    Log.i("MainActivity", "从网络中获取图片");
                }
            }
        };
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       gv = (GridView) findViewById(R.id.gv);
       utils = new ImageLoaderUtils(this, handler);
       gv.setAdapter(new MyAdapter());
    }

    class MyAdapter extends BaseAdapter{

        @Override
        public int getCount() {
            return Images.imagesUrl.length;
        }

        @Override
        public Object getItem(int arg0) {
            return null;
        }

        @Override
        public long getItemId(int arg0) {
            return 0;
        }

        @Override
        public View getView(int arg0, View arg1, ViewGroup arg2) {
            ImageView imageView=new ImageView(MainActivity.this);
            imageView.setTag(Images.imagesUrl[arg0]);
            Bitmap bimap=utils.getBitmap(Images.imagesUrl[arg0]);
            
            //从内存中或缓存获取
            if(bimap!=null){
                imageView.setImageBitmap(bimap);
            }
            return imageView;
        }
        
    }
    
}

package com.example.image;

public class Images {

    public final static String[] imagesUrl=new String[]{
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383299_1976.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383291_6518.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383291_8239.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383290_9329.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383290_1042.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383275_3977.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383265_8550.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383264_3954.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383264_4787.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383264_8243.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383248_3693.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383243_5120.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_3127.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_9576.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_1721.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383219_5806.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383214_7794.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383213_4418.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383213_3557.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383210_8779.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383172_4577.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383166_3407.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383166_2224.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383166_7301.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383165_7197.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383150_8410.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383131_3736.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383130_5094.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383130_7393.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383129_8813.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383100_3554.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383093_7894.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383092_2432.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383092_3071.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383091_3119.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383059_6589.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383059_8814.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383059_2237.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383058_4330.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383038_3602.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382942_3079.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382942_8125.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382942_4881.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382941_4559.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382941_3845.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382924_8955.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382923_2141.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382923_8437.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382922_6166.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382922_4843.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382905_5804.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382904_3362.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382904_2312.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382904_4960.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382900_2418.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382881_4490.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382881_5935.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382880_3865.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382880_4662.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382879_2553.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382862_5375.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382862_1748.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382861_7618.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382861_8606.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382861_8949.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382841_9821.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382840_6603.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382840_2405.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382840_6354.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382839_5779.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382810_7578.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382810_2436.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382809_3883.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382809_6269.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382808_4179.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382790_8326.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382789_7174.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382789_5170.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382789_4118.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382788_9532.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382767_3184.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382767_4772.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382766_4924.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382766_5762.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406382765_7341.jpg"
        
    };
}


package com.example.image;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.util.LruCache;
import android.util.Log;

public class ImageLoaderUtils {

    private File cacheDir;
    private ExecutorService newFixThreadPool;
    private LruCache<String, Bitmap> lruCache;
    private Handler handler;

    public ImageLoaderUtils(Context context, Handler handler) {
        this.handler=handler;
        //内存处理
        // 获取程序的最大内存
        long maxMemory = Runtime.getRuntime().maxMemory();
        // 设置内存的1/8
        int maxSize = (int) (maxMemory / 8);
        lruCache = new LruCache<String, Bitmap>(maxSize) {
            // 计算每张图片的大小
            @Override
            protected int sizeOf(String key, Bitmap value) {
                // 图片的大小是长*宽(像素点)
                int size = value.getRowBytes() * value.getHeight();
                return size;
            }
        };
        // 把图片缓存到该路径下
        cacheDir = context.getCacheDir();
        // 请求网络---开线程
                // 手机 2 -----2*2+1
        newFixThreadPool = Executors.newFixedThreadPool(5);

    }

    /*
     * 获取图片
     */
    public Bitmap getBitmap(String path) {
        // 从内存中获取
        Bitmap bitmap = lruCache.get(path);
        if (bitmap != null) {
            Log.i("MainActivity", "从内存中获取图片");
            return bitmap;
        }
        // 去本地缓存中获取图片
        bitmap = getBitmapFromLocal(path);
        if (bitmap != null) {
            Log.i("MainActivity", "从本地存中获取图片");
            return bitmap;
        }
        // 请求网络获取图片
        getBitmapFromNet(path);
        return null;
    }

    private Bitmap getBitmapFromLocal(String path) {
        try {
            String encode=EncoderUtils.encode(path);
            // 如何获取
            FileInputStream fileInputStream=new FileInputStream(cacheDir+"/"+encode);
            //根据输出流获取图片
            Bitmap bitmap=BitmapFactory.decodeStream(fileInputStream);
            //写到内存中
            lruCache.put(path, bitmap);
        
            return bitmap;
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        
        return null;
    }

    /*
     * 从网络中获取图片
     */
    private void getBitmapFromNet(final String path) {
        newFixThreadPool.execute(new Runnable() {

            @Override
            public void run() {
                try {
                    URL url = new URL(path);
                    HttpURLConnection conn = (HttpURLConnection) url
                            .openConnection();
                    conn.setReadTimeout(5000);
                    conn.setConnectTimeout(5000);
                    int code = conn.getResponseCode();
                    if (code == 200) {
                        InputStream inputStream = conn.getInputStream();
                        Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                        Message message = new Message();
                        message.what = 101;
                        message.obj = bitmap;
                        Bundle bundle=new Bundle();
                        bundle.putString("tag", path);
                        message.setData(bundle);
                        handler.sendMessage(message);
                        //存到缓存内存中
                        saveBitmaoToLocal(bitmap,path);
                        //存到内存中
                        lruCache.put(path, bitmap);
                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }
    /*/
     * 将图片存储到本地缓存
     */
    public void saveBitmaoToLocal(Bitmap bitmap,String path){
        try {
            String encode=EncoderUtils.encode(path);
            //本地
            FileOutputStream fileOutputStream=new FileOutputStream(cacheDir+"/"+encode);
            
            //将图片写入到文件中
            //format图片格式
            //quality压缩的质量
            bitmap.compress(CompressFormat.JPEG, 100, fileOutputStream);
            
        
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }

}




package com.example.image;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class EncoderUtils {
    /**
     * Md5Encoder
     *
     * @param string
     * @return
     * @throws Exception
     */
    public static String encode(String string) throws Exception {
        byte[] hash = MessageDigest.getInstance("MD5").digest(
                string.getBytes("UTF-8"));
        StringBuilder hex = new StringBuilder(hash.length * 2);
        for (byte b : hash) {
            if ((b & 0xFF) < 0x10) {
                hex.append("0");
            }
            hex.append(Integer.toHexString(b & 0xFF));
        }
        return hex.toString();
    }
}






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