三级缓存的使用框架

来源：互联网发布：淘宝店铺收入该怎么算编辑：程序博客网时间：2024/04/29 16:42

package liujianrui.bawei.com.three_level_buffer.utils;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Environment;import android.os.Handler;import android.os.Message;import android.util.DisplayMetrics;import android.util.Log;import android.widget.ImageView;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.lang.ref.SoftReference;import java.util.HashMap;import java.util.Map;import cz.msebera.android.httpclient.HttpResponse;import cz.msebera.android.httpclient.client.HttpClient;import cz.msebera.android.httpclient.client.methods.HttpGet;import cz.msebera.android.httpclient.impl.client.DefaultHttpClient;/** * Created by ASUS on 2017/3/23. */   //这是一个工具类：可以自己封装，Mainactivity需要自己写，自己调用：public class Bitmaputils {//这是执行第一个网络，    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            super.handleMessage(msg);            switch (msg.what) {                case 0:                    ImageViewToBitmap imageViewToBitmap = (ImageViewToBitmap) msg.obj;                    imageViewToBitmap.iv.setImageBitmap(imageViewToBitmap.bitmap);                    Log.i("xxxxl",imageViewToBitmap.bitmap+"");                    break;            }        }    };//软引用     根据键值获取Bitmap    private Map<String, SoftReference<Bitmap>> map = new HashMap<String, SoftReference<Bitmap>>();    //图片本地缓存路径    String path= Environment.getExternalStorageDirectory()+"/imgache";    File file=new File(path);    Context context;    public Bitmaputils(Context context) {        this.context = context;          if(!file.exists())          {              file.mkdirs();          }    }    //加载图片的方法    public void display(ImageView iv, String url) {        //内存缓存        Bitmap bitmap = loadMemory(url);        if (bitmap != null) {            iv.setImageBitmap(bitmap);            Log.i("axxx",bitmap+"");        } else {            //sdcard缓存            bitmap = loadSD(url);            if (bitmap != null) {                iv.setImageBitmap(bitmap);                Log.i("xxxx",bitmap+"");            } else {                //网络缓存                loadInternetImage(iv, url);            }        }    }    //获取网络图片    private void loadInternetImage(ImageView iv, String url) {        //开子线程做耗时操作        new Thread(new DownloadImage(iv, url)).start();    }      private class DownloadImage implements Runnable{          ImageView iv;          String url;          private FileOutputStream fileOutputStream;          private InputStream inputStream;          public DownloadImage(ImageView iv, String url) {              this.iv = iv;              this.url = url;          }          @Override          public void run() {              HttpClient clent = new DefaultHttpClient();              HttpGet get = new HttpGet(url);              try {                  HttpResponse execute = clent.execute(get);                  if(execute.getStatusLine().getStatusCode() == 200)                  {                      inputStream = execute.getEntity().getContent();                      String name = getFileName(url);                      File filename = new File(file, name);                      fileOutputStream = new FileOutputStream(filename);                      byte[] buffer = new byte[1024];                      int len = 0;                      while ((len = inputStream.read(buffer)) != -1) {                          fileOutputStream.write(buffer, 0, len);                      }                      inputStream.close();                      fileOutputStream.close();                      //sdcard缓存                      Bitmap bitmap = loadSD(url);                      //ImageView转换成Bitmap转换成Bitmap                      ImageViewToBitmap ivtb = new ImageViewToBitmap(iv, bitmap);                      Message message = Message.obtain(handler, 0, ivtb);                      message.sendToTarget();                  }              } catch (Exception e) {                  e.printStackTrace();              }          }      }    //获取图片的名称    private String getFileName(String url) {        return Md5Utils.encode(url) + ".jpg";    }    //获取本地图片    private Bitmap loadSD(String url) {        String name = getFileName(url);        File filename = new File(file, name);        if (filename.exists()) {            //BitmapFactory选项            BitmapFactory.Options options = new BitmapFactory.Options();            //加载图片宽高            options.inJustDecodeBounds = true;            BitmapFactory.decodeFile(name, options);            //获取图片和手机屏幕宽高            int outWidth = options.outWidth;            int outHeight = options.outHeight;            DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();            int widthPixels = displayMetrics.widthPixels;            int heightPixels = displayMetrics.heightPixels;            //图片跟手机屏幕进行比对            int scale = 0;            int scaleX = outWidth / widthPixels;            int scaleY = outHeight / heightPixels;            scale = scaleX > scaleY ? scaleX : scaleY;            if (scale == 0) {                scale = 1;            }            options.inJustDecodeBounds = false;            options.inSampleSize = scale;            Bitmap bitmap = BitmapFactory.decodeFile(filename.getAbsolutePath(), options);            //内存缓存            SoftReference<Bitmap> value = new SoftReference<Bitmap>(bitmap);            map.put(name, value);            return bitmap;        }        return null;    }    //ImageView转换成Bitmap转换成Bitmap    private class ImageViewToBitmap {        ImageView iv;        Bitmap bitmap;        public ImageViewToBitmap(ImageView iv, Bitmap bitmap) {            this.iv = iv;            this.bitmap = bitmap;        }    }    //缓存到内存    private Bitmap loadMemory(String url) {        SoftReference<Bitmap> value = map.get(url);        if (value != null) {            Bitmap bitmap = value.get();            return bitmap;        }        return null;    } }

谨记需建一个类

public class Md5Utils {    public static String encode(String password){        try {            MessageDigest digest = MessageDigest.getInstance("MD5");            byte[] result = digest.digest(password.getBytes());            StringBuffer sb = new StringBuffer();            for(byte b : result){                int number = (int)(b & 0xff) ;                String str = Integer.toHexString(number);                if(str.length()==1){                    sb.append("0");                }                sb.append(str);            }            return sb.toString();        } catch (Exception e) {            e.printStackTrace();            //can't reach            return "";        }    }}

0 0