【文件属性】：
文件名称：图片缓存机制代码
文件大小：2.04MB
文件格式：ZIP
更新时间：2019-02-16 03:58:59
图片缓存
用于类似图库，缓存，所困、缩略图
package com.example.cache;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.Map;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapFactory.Options;
import android.util.DisplayMetrics;
/**
* 1.从内存中加载
* 2.本地缓存中加载
* 3.本地加载
* @author Administrator
*
*/
public class LoadCacheImageTool {
private Activity activity;
private Map> cacheMap;
public LoadCacheImageTool(Activity activity){
this.activity = activity;
this.cacheMap = new HashMap>();
}
public Bitmap loadCacheImage(String imagePath){
Bitmap bitmap = null;
if (cacheMap.containsKey(imagePath)) {
bitmap = cacheMap.get(imagePath).get();
if (bitmap!=null) {
return bitmap;
}
}
bitmap = loadLocalCacheImage(imagePath);
cacheMap.put(imagePath, new SoftReference(bitmap));
return bitmap;
}
///mnt/sdcard/bk.png
///mnt/sdcard/cache/bk.png.cache
private Bitmap loadLocalCacheImage(String imagePath) {
Bitmap bitmap = null;
String cacheImagePath = getCacheImagePath(imagePath);
File cacheFile = new File(cacheImagePath);
if (!cacheFile.exists()) {
bitmap = loadLocalBigImage(imagePath);
saveToCacheDir(bitmap,cacheImagePath);
}else{
try {
bitmap = BitmapFactory.decodeStream(new FileInputStream(cacheFile));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return bitmap;
}
private String getCacheImagePath(String imagePath) {
String cacheDir = new File(imagePath).getParent()+"/cache/";
if (!new File(cacheDir).exists()) {
new File(cacheDir).mkdirs();
}
String newImageName = new File(imagePath).getName()+".cache";
String newImagePath = cacheDir+newImageName;
return newImagePath;
}
private void saveToCacheDir(Bitmap bitmap, String cacheImagePath) {
FileOutputStream fos = null;
try {
fos = new FileOutputStream(cacheImagePath);
if (bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos)) {
fos.flush();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public Bitmap loadLocalBigImage(String imagePath){
DisplayMetrics metrics = new DisplayMetrics();
activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
int screenWidth = metrics.widthPixels;
int screenHeight = metrics.heightPixels;
System.out.println("screenWidth:"+screenWidth+"=="+screenHeight);
Options options = new Options();
//加载边框 一定options.inJustDecodeBounds = true;
options.inJustDecodeBounds = true;
Bitmap bitmap = BitmapFactory.decodeFile(imagePath, options);
int imageWidth = options.outWidth;
int imageHeight = options.outHeight;
System.out.println("imageWidth:"+imageWidth+"=="+imageHeight);
int scaleX = (int) Math.ceil(imageWidth/(float)screenWidth);
int scaleY = (int) Math.ceil(imageHeight/(float)screenHeight);
if (scaleX>1||scaleY>1) {
options.inSampleSize = (scaleX>scaleY)?scaleX:scaleY;
}
System.out.println("inSamPle:"+options.inSampleSize);
options.inJustDecodeBounds =false;
//图片的质量
options.inPreferredConfig = Bitmap.Config.ARGB_4444;
//内存上的处理 可删除
options.inInputShareable = true;
options.inPurgeable = true;
try {
bitmap = BitmapFactory.decodeStream(new FileInputStream(imagePath), null, options);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return bitmap;
}
}
【文件预览】：
20150724
----缓存图片()
--------.project(848B)
--------project.properties(563B)
--------src()
--------AndroidManifest.xml(1KB)
--------res()
--------assets()
--------gen()
--------libs()
--------.classpath(475B)
--------proguard-project.txt(781B)
--------ic_launcher-web.png(50KB)
--------bin()
----ͼƬ()
--------.project(842B)
--------project.properties(563B)
--------src()
--------AndroidManifest.xml(951B)
--------res()
--------assets()
--------gen()
--------libs()
--------.classpath(475B)
--------proguard-project.txt(781B)
--------ic_launcher-web.png(50KB)
--------bin()
