android利用lrucache存储图片的demo

代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="图片 缓存 demo"/>
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="远程图片地址"/>
<EditText android:layout_width="0dip" android:layout_weight="1" android:layout_height="wrap_content" android:id="@+id/txt_img1"/>
</LinearLayout>
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="开始抓取" android:id="@+id/btn_fetch_img1"/>
<ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/img_res1"/>
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/txt_tips_1"/>
<ScrollView android:layout_width="fill_parent" android:layout_height="wrap_content">
<LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" android:id="@+id/panel_imgList">

</LinearLayout>
</ScrollView>

</LinearLayout>

package com.example.apppractise.app;

import android.annotation.TargetApi;
import android.app.Activity;
import android.graphics.Bitmap;
import android.media.Image;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.util.LruCache;
import android.view.View;
import android.widget.*;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.ImageRequest;
import com.android.volley.toolbox.Volley;

/**
* Created by Administrator on 2015/7/3.
*/
public class ImageCacheDemo extends Activity {

private LruCache<String,Bitmap> imgcache;
RequestQueue queue;
private static final String TAG="image cache demo";
private EditText txt_img1;
private Button btn_fetch_img1;
private ImageView img_res1;
private LinearLayout layout_imgList;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.image_cache_demo);
queue= Volley.newRequestQueue(this);
caculateMemory();
initImgCache();
initUI();
initEvents();
}

private void initImgCache(){
int _size_space=(int)(Runtime.getRuntime().maxMemory()/1024);
_size_space=_size_space/8;
imgcache=new LruCache<String, Bitmap>(_size_space){
@Override
protected int sizeOf(String key,Bitmap bitmap){

return bitmap.getByteCount()/1024;
}
};

}
private void caculateMemory(){
int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
Log.d(TAG,"当前最大容量："+maxMemory+"mb");
Long free_memory=(Long)(Runtime.getRuntime().freeMemory()/1024);
Log.d((TAG),"剩余容量："+free_memory+"mb");

}
private void initUI(){

txt_img1=(EditText)findViewById(R.id.txt_img1);
btn_fetch_img1=(Button)findViewById(R.id.btn_fetch_img1);
img_res1=(ImageView)findViewById(R.id.img_res1);
layout_imgList=(LinearLayout)findViewById(R.id.panel_imgList);
}
private void initEvents(){
btn_fetch_img1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String path=txt_img1.getText().toString();
if(path.length()<=0){
Toast.makeText(ImageCacheDemo.this, "请输入需要显示的图片的路径。", Toast.LENGTH_SHORT).show();
return;
}
Log.e("log","开始抓图片："+path);
if(imgcache.get(path)!=null){

Bitmap _bmp=imgcache.get(path);
appendImage(_bmp);
Log.d(TAG,"直接从内存里面拿出图片缓存来用");
caculateMemory();
return;
}
ImageRequest imageRequest=new ImageRequest(path, new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap response) {
imgcache.put(path,response);
//img_res1.setImageBitmap(response);
appendImage(response);
Log.e("log","抓取成功");
caculateMemory();
}
}, 400, 400, Bitmap.Config.ARGB_4444, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
//img_res1.setImageResource(R.drawable.ui_imgselect_albums_bg);
Log.e("log","抓取失败");
}
});
queue.add(imageRequest);
}
});
}

private void appendImage(Bitmap bitmap){
ImageView imageView=new ImageView(this);
imageView.setImageBitmap(bitmap);
layout_imgList.addView(imageView);
}
}