ImageLoader三级缓存
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需要配置权限
<uses-permission android:name="android.permission.INTERNET" /><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>需要配置依赖compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
public class MainActivity extends AppCompatActivity { String[] uri=new String[]{ "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uplds/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383299_1976.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383291_6518.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383291_8239.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383290_9329.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383290_1042.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383275_3977.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383265_8550.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383264_3954.jpg", "http://img.my.csdn.net/uploads/201407/26/1406383264_4787.jpg", }; private Handler handler = new Handler(){ @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (msg.what == 0) { Bitmap bitmap = (Bitmap) msg.obj; // 设置给imageView String tag = msg.getData().getString("tag"); // 根据标记取出imageView ImageView imageView = (ImageView) gv.findViewWithTag(tag); if (imageView != null && bitmap != null) { // 从网络获取图片 imageView.setImageBitmap(bitmap); Log.i("tag", "从网络中获取图片"); } } } }; private GridView gv; ImageUtils imagUtils; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imagUtils = new ImageUtils(this,handler); gv = (GridView) findViewById(R.id.gv); gv.setAdapter(new MyAdapter()); } class MyAdapter extends BaseAdapter { @Override public int getCount() { // TODO Auto-generated method stub return uri.length; } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ImageView iv = new ImageView(MainActivity.this); iv.setTag(uri[position]); //去图片; Bitmap bitmap = imagUtils.getBitmap(uri[position]); // 从内存中或者缓存中 if (bitmap != null) { iv.setImageBitmap(bitmap); } // 获取图片 return iv; } }}
Utils类
/** * author:Created by WangZhiQiang on 2017-09-04. * 处理三级缓存 * 内存缓存(LruCache-->最近最少使用算法,当缓存慢的时候,自动把最近使用最少的删除,腾出来的空间添加新的缓存内容) * sd卡缓存 * 网络 */public class ImageUtils { Handler handler; LruCache<String, Bitmap> lrucache; private final ExecutorService executorService; private final File cacheDir; public ImageUtils(Context context, Handler handler){ //获取到手机上最大的内存 long maxmemory = Runtime.getRuntime().maxMemory(); //让你的图片加载只占总内存的八分之一多出的话最近最少LruCache删除 int max=(int)(maxmemory/8); this.handler=handler; //得到本app在sd上缓存的文件夹谷歌提供的sd卡上文件夹 cacheDir = context.getCacheDir(); //初始化线程池创建5个供程序使用 executorService = Executors.newFixedThreadPool(5); //实例化LruCacha来进行每次最近最少删除 lrucache = new LruCache<String, Bitmap>(max){ //每次缓存调用这个方法 @Override protected int sizeOf(String key, Bitmap value) { return value.getRowBytes()*value.getHeight(); } }; } /** * 取图片, * * @param path * @return */ public Bitmap getBitmap(String path){ //向项目缓存里面获取图片 Bitmap bitmap = lrucache.get(path); //判断图片有没有取出来 if(bitmap!=null){ System.out.println("我走了本地缓存"); return bitmap; } //从本直去取,sd卡去取bitmap bitmap = getBitMapFromLocal(path); if (bitmap != null) { System.out.println("我走了本地缓存"); return bitmap; } // 从网络去取 getBitmapFromNet(path); return null; } /** * 从sd卡获取图片 * * @param path * @return */ private Bitmap getBitMapFromLocal(String path) { try { String encode = EncoderUtils.encode(path); FileInputStream fileInputStream = new FileInputStream(cacheDir+ "/" + encode); Bitmap bitmap = BitmapFactory.decodeStream(fileInputStream); //存到内存 lrucache.put(path, bitmap); return bitmap; } catch (Exception e) { e.printStackTrace(); } return null; } /** * 从网络 * * @param path */ private void getBitmapFromNet(final String path) { //用线程池里的线程执行请求网络操作; executorService.execute(new Runnable() { @Override public void run() { try { URL url = new URL(path); HttpURLConnection connection = (HttpURLConnection) url .openConnection(); connection.setConnectTimeout(5000); connection.setReadTimeout(5000); int responseCode = connection.getResponseCode(); if (responseCode == 200) { InputStream inputStream = connection.getInputStream(); Bitmap bitmap = BitmapFactory.decodeStream(inputStream); Message msg = new Message(); msg.what = 111; msg.obj = bitmap; Bundle data = new Bundle(); data.putString("tag", path); msg.setData(data); handler.sendMessage(msg); //缓存到本地 saveBitmapToLocal(bitmap, path); //缓存到内存 lrucache.put(path, bitmap); } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }); } protected void saveBitmapToLocal(Bitmap bitmap, String path) { try { String encode = EncoderUtils.encode(path); FileOutputStream fileOutputStream = new FileOutputStream(cacheDir + "/" + encode); //图片二次裁剪 bitmap.compress(Bitmap.CompressFormat.JPEG, 80, fileOutputStream); } catch (Exception e) { e.printStackTrace(); } }}Md5加密类
/** * author:Created by WangZhiQiang on 2017-09-04. * 工具类,把对url进行md5加密,加密后以字符串的形式返回; * 缓存的时候用key(url加密后的字符串)对应value(bitmap) */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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