Imageloader基本使用

在AndroidManifest.xml中配置权限*在application中配置name属性

<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"/>
<application
        android:name=".MApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

在Gradle中配置依赖

compile 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

创建一个全局上下文类 继承的是Application ,在onCreate方法中获取ImageLoader实例

import android.app.Application;

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

/**
 * author:Created by WangZhiQiang on 2017-11-06.
 * 这个是整个程序的全局Context;
 * 程序一启动,就会先启动MApp;它比MainActivity要早;程序退出这个MApp才销毁;
 */

public class MApp extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        //初始化Imageloader框架;链式开发思想
        //configuration 是imageloader的参数;
        ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(this).build();
        //获取ImageLoader的实例初始化配置参数;
        ImageLoader.getInstance().init(configuration);


    }
}

在activity中获取实例显示数据

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

import com.nostra13.universalimageloader.core.ImageLoader;

public class MainActivity extends AppCompatActivity {

    private ImageView iv;
    private ImageLoader instance;
    String urlBitmap = "https://img-my.youkuaiyun.com/uploads/201407/26/1406383265_8550.jpg";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        instance = ImageLoader.getInstance();



        iv = (ImageView) findViewById(R.id.iv);
        iv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                instance.displayImage(urlBitmap,iv);
            }
        });


    }
}