softreference_referencequeue作用_java 虚引用

softReference缓存的对象，只有当虚拟机内存不足的才会回收，很好的避免了OOM。softreference

package cache;

import java.lang.ref.SoftReference;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.concurrent.ConcurrentHashMap;

import android.graphics.Bitmap;

import android.os.Handler;

import android.widget.ImageView;

public class FileServiceByMemoary extends FileServiceAbstractDetails {

@Override

public void loadFileToMap() {

// for memory, nothing to do.

}

@Override

public void getBitmap(String url, ImageView imageView,

Bitmap defaultBitmap, Integer scrollState) {

resetPurgeTimer();

// scrollState 0:停止状态，需要加载图片(cache -> network)

// scrollState 1/2:滚动状态，此时就用cache图片，如果cache没有就用默认defaultBitmap

Bitmap bitmap = getBitmapFromCache(url);

if (scrollState != SCROLL_STATUS_STOP) {// 处于滚动状态

if (bitmap == null) {

imageView.setImageBitmap(defaultBitmap);

} else {

imageView.setImageBitmap(bitmap);

}

return;

}

if (bitmap == null) {

forceDownload(url, imageView, defaultBitmap);

} else {

cancelPotentialDownload(url, imageView);

imageView.setImageBitmap(bitmap);

}

}

// public void setMode(Mode mode) {

// this.mode = mode;

// clearCache();

// }

private static final int HARD_CACHE_CAPACITY = 30;

private static final int DELAY_BEFORE_PURGE = 10 * 1000; // in milliseconds

private final static HashMap<String, Bitmap> mHardBitmapCache = new LinkedHashMap<String, Bitmap>(

HARD_CACHE_CAPACITY, 0.75f, true) {

private static final long serialVersionUID = 1L;

@Override

protected boolean removeEldestEntry(

本文来自电脑杂谈，转载请注明本文网址：
http://www.pc-fly.com/a/ruanjian/article-49624-1.html