ImageLoader和wifi网络的判断

最新推荐文章于 2020-05-26 13:20:12 发布

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#wi-fi #imageloader的使用

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本文介绍了一个基于Android平台的应用程序如何通过自定义Application类来初始化并配置ImageLoader库，包括缓存策略、线程池大小及图片加载选项等关键参数。

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创建一个类继承Application

package com.wzq.imageloaderdemo1;

import android.app.Application;
import android.util.Log;

import com.nostra13.universalimageloader.cache.memory.impl.UsingFreqLimitedMemoryCache;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
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;

/**
* 这个是系统全局的Application, 它就是系统生命周期最长的上下文;
* 系统已启动,并不是直接进入MainActivity;而是先进入Application;
* 重写他的目的是,初始化系统全局的一些参数;比如imageLoader的全局配置;
* Application的生命周期和app的生命周期一样,
*/

public class App extends Application {

**//在Mani.xml <application中配置 android:name=".App"
    导入依赖或jar包**

//这些配置都可以省略
@Override
public void onCreate() {
    super.onCreate();
    Log.e("MyApplication", "我走了application");
    ImageLoaderConfiguration config = new ImageLoaderConfiguration
            .Builder(this)
            .memoryCacheExtraOptions(480, 800) // max width, max height，即保存的每个缓存文件的最大长宽
            .threadPoolSize(5)//线程池内加载的数量
            .threadPriority(Thread.NORM_PRIORITY - 2)
            .denyCacheImageMultipleSizesInMemory()
            .memoryCache(new UsingFreqLimitedMemoryCache(2 * 1024 * 1024)) // You can pass your own memory cache implementation/你可以通过自己的内存缓存实现
            .memoryCacheSize(2 * 1024 * 1024)
            .tasksProcessingOrder(QueueProcessingType.LIFO)
            .defaultDisplayImageOptions(DisplayImageOptions.createSimple())
            .imageDownloader(new BaseImageDownloader(this, 5 * 1000, 30 * 1000)) // connectTimeout (5 s), readTimeout (30 s)超时时间
            .writeDebugLogs() // Remove for release app
            .build();//开始构建

//上面的.build()方法和这两行代码必须要写

//初始化imageloader;
    ImageLoader.getInstance().init(config);
    //初始化 代码统计;

    }

}

加权限

<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" />

主界面

package com.wzq.imageloaderdemo1;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;

import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;

public class MainActivity extends AppCompatActivity {

String[] images = {
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383264_8243.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383248_3693.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383243_5120.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_3127.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_9576.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383242_1721.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383219_5806.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383214_7794.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383213_4418.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383213_3557.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383210_8779.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383172_4577.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383166_3407.jpg",
        "https://img-my.youkuaiyun.com/uploads/201407/26/1406383166_2224.jpg"
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageView imageView = (ImageView) findViewById(R.id.imageView);
    //得到imageLoader的实例;
    ImageLoader imageLoader = ImageLoader.getInstance();

    //这三个方法必须写
    DisplayImageOptions displayImageOptions = new DisplayImageOptions.Builder()
            .showImageOnLoading(R.mipmap.ic_launcher) //设置图片在下载期间显示的图片
            .showImageForEmptyUri(R.mipmap.ic_launcher)//设置图片Uri为空或是错误的时候显示的图片
            .showImageOnFail(R.mipmap.ic_launcher)  //设置图片加载/解码过程中错误时候显示的图片

            .build();
    imageLoader.displayImage(images[2], imageView);

    }
}

布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.wzq.imageloaderdemo1.MainActivity">

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<ImageView
    android:id="@+id/imageView"
    android:layout_width="199dp"
    android:layout_height="149dp"
    android:layout_marginBottom="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginRight="8dp"
    android:layout_marginTop="8dp"
    app:layout_constraintBottom_toTopOf="@+id/textView"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:srcCompat="@mipmap/ic_launcher"
    tools:layout_editor_absoluteX="17dp"
    tools:layout_editor_absoluteY="-1dp" />

</android.support.constraint.ConstraintLayout>

wifi网络的判断

加权限

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

package com.wzq.wifidemo;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

public class Utils {

/**
 * 返回值 -1：没有网络  1：WIFI网络   3：net网络
 */
public static int getNetype(Context context) {
    int netType = -1;
    ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
    if (networkInfo == null) {
        return netType;
    }
    int nType = networkInfo.getType();
    if (nType == ConnectivityManager.TYPE_MOBILE) {
        netType = 2;
    } else if (nType == ConnectivityManager.TYPE_WIFI) {
        netType = 1;
    }
    return netType;
    }
}

主界面
package com.wzq.wifidemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Log.e("TAG", "netType: "+  Utils.getNetype(this));

    }
}