【移动应用开发技术】Android中如何使用Universal-Image-Loader图片异步加载框架

【移动应用开发技术】Android中如何使用Universal-Image-Loader图片异步加载框架

运行流程：/upload/information/20200623/125/123240.png使用步骤：实例：UniversalImageLoaderDemo/upload/information/20200623/125/123241.jpg运行效果：/upload/information/20200623/125/123242.jpgAndroidManifest.xml<?xml

version="1.0"

encoding="utf-8"?>

<manifest

xmlns:android="/apk/res/android"

package="com.rainsong.universalimageloaderdemo"

android:versionCode="1"

android:versionName="1.0"

>

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="19"

/>

<uses-permission

android:name="android.permission.WRITE_EXTERNAL_STORAGE"

/>

<uses-permission

android:name="android.permission.INTERNET"

/>

<application

android:name="com.rainsong.universalimageloaderdemo.UILApplication"

android:allowBackup="true"

android:icon="@drawable/logo"

android:label="@string/app_name"

android:theme="@style/AppTheme"

>

<activity

android:name="com.rainsong.universalimageloaderdemo.MainActivity"

android:label="@string/app_name"

>

<intent-filter>

<action

android:name="ent.action.MAIN"

/>

<category

android:name="ent.category.LAUNCHER"

/>

</intent-filter>

</activity>

</application>

</manifest>布局文件：activity_main.xml<?xml

version="1.0"

encoding="utf-8"?>

<LinearLayout

xmlns:android="/apk/res/android"

xmlns:tools="/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

tools:context=".MainActivity"

>

<ListView

android:id="@+id/list"

android:layout_width="match_parent"

android:layout_height="match_parent"

>

</ListView>

</LinearLayout>布局文件：item_list.xml<?xml

version="1.0"

encoding="utf-8"?>

<LinearLayout

xmlns:android="/apk/res/android"

android:layout_width="match_parent"

android:layout_height="wrap_content"

>

<ImageView

android:id="@+id/image"

android:layout_width="72dip"

android:layout_height="72dip"

android:layout_margin="3dip"

android:adjustViewBounds="true"

android:contentDescription="@string/descr_image"

android:scaleType="centerCrop"

/>

<TextView

android:id="@+id/text"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_gravity="start|center_vertical"

android:layout_marginLeft="20dip"

android:textSize="22sp"

/>

</LinearLayout>Java源代码文件：UILApplication.javapackage

com.rainsong.universalimageloaderdemo;

import

java.io.File;

import

com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;

import

com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;

import

com.nostra13.universalimageloader.cache.memory.impl.UsingFreqLimitedMemoryCache;

import

com.nostra13.universalimageloader.core.ImageLoader;

import

com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import

com.nostra13.universalimageloader.core.assist.QueueProcessingType;

import

com.nostra13.universalimageloader.core.download.BaseImageDownloader;

import

com.nostra13.universalimageloader.utils.StorageUtils;import

android.app.Application;

import

android.content.Context;

public

class

UILApplication

extends

Application

{

@Override

public

void

onCreate()

{

super.onCreate();

initImageLoader(getApplicationContext());

}

public

static

void

initImageLoader(Context

context)

{

//缓存文件的目录

File

cacheDir

=

StorageUtils.getOwnCacheDirectory(context,

"universalimageloader/Cache");

ImageLoaderConfiguration

config

=

new

ImageLoaderConfiguration.Builder(context)

.memoryCacheExtraOptions(480,

800)

//

max

width,

max

height，即保存的每个缓存文件的最大长宽

.threadPoolSize(3)

//线程池内线程的数量

.threadPriority(Thread.NORM_PRIORITY

-

2)

.denyCacheImageMultipleSizesInMemory()

.diskCacheFileNameGenerator(new

Md5FileNameGenerator())

//将保存的时候的URI名称用MD5

加密

.memoryCache(new

UsingFreqLimitedMemoryCache(2

*

1024

*

1024))

.memoryCacheSize(2

*

1024

*

1024)

//

内存缓存的最大值

.diskCacheSize(50

*

1024

*

1024)

//

SD卡缓存的最大值

.tasksProcessingOrder(QueueProcessingType.LIFO)

//

由原先的discCache

->

diskCache

.diskCache(new

UnlimitedDiscCache(cacheDir))//自定义缓存路径

.imageDownloader(new

BaseImageDownloader(context,

5

*

1000,

30

*

1000))

//

connectTimeout

(5

s),

readTimeout

(30

s)超时时间

.writeDebugLogs()

//

Remove

for

release

app

.build();

//全局初始化此配置

ImageLoader.getInstance().init(config);

}

}Java源代码文件：MainActivity.javapackage

com.rainsong.universalimageloaderdemo;

import

com.nostra13.universalimageloader.core.DisplayImageOptions;

import

com.nostra13.universalimageloader.core.ImageLoader;

import

com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;

import

android.os.Bundle;

import

android.app.Activity;

import

android.view.Menu;

import

android.view.MenuItem;

import

android.view.View;

import

android.view.ViewGroup;

import

android.widget.BaseAdapter;

import

android.widget.ImageView;

import

android.widget.ListView;

import

android.widget.TextView;

public

class

MainActivity

extends

Activity

{

private

ImageLoader

imageLoader;

private

ListView

lv;

private

String[]

imageUrls;

private

DisplayImageOptions

options;

@Override

protected

void

onCreate(Bundle

savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

imageLoader

=

ImageLoader.getInstance();

lv

=

(ListView)findViewById(R.id.list);

imageUrls

=

Constants.images;

//

使用DisplayImageOptions.Builder()创建DisplayImageOptions

options

=

new

DisplayImageOptions.Builder()

.showImageOnLoading(R.drawable.ic_stub)

//

设置图片下载期间显示的图片

.showImageForEmptyUri(R.drawable.ic_empty)

//

设置图片Uri为空或是错误的时候显示的图片

.showImageOnFail(R.drawable.ic_error)

//

设置图片加载或解码过程中发生错误显示的图片

.cacheInMemory(true)

//

设置下载的图片是否缓存在内存中

.cacheOnDisk(true)

//

设置下载的图片是否缓存在SD卡中

.displayer(new

RoundedBitmapDisplayer(20))

//

设置成圆角图片

.build();

//

构建完成

lv.setAdapter(new

ItemListAdapter());

}

@Override

public

boolean

onCreateOptionsMenu(Menu

menu)

{

//

Inflate

the

menu;

this

adds

items

to

the

action

bar

if

it

is

present.

getMenuInflater().inflate(R.menu.main,

menu);

return

true;

}

@Override

public

boolean

onOptionsItemSelected(MenuItem

item)

{

switch

(item.getItemId())

{

case

R.id.item_clear_memory_cache:

ImageLoader.getInstance().clearMemoryCache();

return

true;

case

R.id.item_clear_disc_cache:

ImageLoader.getInstance().clearDiskCache();

return

true;

default:

return

false;

}

}

class

ItemListAdapter

extends

BaseAdapter

{

@Override

public

int

getCount()

{

//

TODO

Auto-generated

method

stub

return

imageUrls.length;

}

@Override

public

Object

getItem(int

position)

{

//

TODO

Auto-generated

method

stub

return

imageUrls[position];

}

@Override

public

View

getView(int

position,

View

convertView,

ViewGroup

parent)

{

//

TODO

Auto-generated

method

stu