欧美bbbwbbbw肥妇,免费乱码人妻系列日韩,一级黄片

直接應(yīng)用項(xiàng)目中的Android圖片緩存技術(shù)

 更新時(shí)間:2016年04月28日 15:09:00   作者:??double?  
這篇文章主要為大家詳細(xì)介紹了直接應(yīng)用項(xiàng)目中的Android圖片緩存技術(shù),簡(jiǎn)單、方便、高效,感興趣的小伙伴們可以參考一下

前不久搞的Android圖片緩存,剛開(kāi)始引入開(kāi)源的框架,用著還行,但是在開(kāi)發(fā)中遇到問(wèn)題,就比如universal-image-loader-1.9.5.jar這個(gè)框架吧,在加載圖片的時(shí)候自定義imageview無(wú)法加載,可能是存在以下問(wèn)題吧,況且導(dǎo)入框架導(dǎo)致開(kāi)發(fā)的項(xiàng)目包越來(lái)越大,基于上面的這幾種情況,于是我就想自己寫一個(gè)圖片三級(jí)緩存的工具。
簡(jiǎn)要分析:剛開(kāi)始想,圖片的加載顯示無(wú)非是先檢查內(nèi)存里面有沒(méi)有,沒(méi)就去文件里面找,若是文件里面沒(méi)有的話就去開(kāi)啟網(wǎng)絡(luò)下載,這樣也符合開(kāi)發(fā)中的大部分需求,而且效率肯定要高一點(diǎn),在某些場(chǎng)合如快速滑動(dòng)listview時(shí)從文件中加載圖片就沒(méi)有從內(nèi)存中加載得快。先來(lái)看看效果吧!
這是第一次加載出來(lái)的圖片,當(dāng)然是網(wǎng)上的一張圖片:

圖片加載出來(lái)了,我們要看看日志,日志不會(huì)說(shuō)謊,我截圖的日志

剛才是本地和內(nèi)存都沒(méi)有那就的去網(wǎng)絡(luò)下載了,所有日志打印的是開(kāi)啟網(wǎng)絡(luò)下載
然而第二次進(jìn)入應(yīng)用的時(shí)候呢?還回去開(kāi)啟網(wǎng)絡(luò)下載嗎?那肯定不會(huì)的,要不這樣要它有啥用呢?
看看吧這就是第二次進(jìn)入應(yīng)用的時(shí)候的日志

從文件中加載圖片,不在需要開(kāi)啟網(wǎng)絡(luò)下載直接從文件中獲取,好了,這樣問(wèn)題就來(lái)了,從文件中讀取肯定效率不好呀,沒(méi)有直接從內(nèi)存中讀取快吧!我們調(diào)用系統(tǒng)維護(hù)好的一個(gè)算法,最近最少使用算法,這個(gè)算法是在我學(xué)操作系統(tǒng)的時(shí)候?qū)W到的,當(dāng)時(shí)老師講了一下,不過(guò)還好,能在項(xiàng)目中用到老師講的東西,對(duì)此,以為就這個(gè)就完了?我們應(yīng)該把文件中的圖片讀取到內(nèi)存中,這樣防止像listview這樣的快速滑動(dòng)產(chǎn)生的錯(cuò)位bug。下面看看我在快速滑動(dòng)時(shí)的效果:

加載的圖片都是從內(nèi)存中獲取,這樣在效果上面就很好的啦!
好的,這么好的圖片三級(jí)緩存,那到底怎么實(shí)現(xiàn)的呢以及到底怎么用的呢?下面就貼出我寫的代碼吧!讓小伙伴看看,順便優(yōu)化優(yōu)化!

package com.example.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.support.v4.util.LruCache;
import android.util.Log;


/**
 * 圖片的三級(jí)緩存工具類{日后項(xiàng)目需要}
 * @author double 江
 *
 */
public class ImageCachceUitl {
  public static final int SUCCSEE = 0;
  public static final int FAIL = 1;
  private Context context;
  private LruCache<String, Bitmap> cache;//lru算法集合,string是圖片的url,bitmap為圖片的值類型
  private File cacheDir;
  Handler handler;
  private ExecutorService executorService;//維護(hù)線性池
  public ImageCachceUitl(Context context ,Handler handler){
    this.context=context;
    this.handler=handler;
    cacheDir=context.getCacheDir();//獲得cache文件夾
    //維護(hù)幾個(gè)網(wǎng)絡(luò)線程下載圖片
    executorService=Executors.newFixedThreadPool(5);
    int maxSize=(int) (Runtime.getRuntime().maxMemory()/8);//獲得運(yùn)行環(huán)境的內(nèi)存大小的1/8
    cache=new LruCache<String, Bitmap>(maxSize){
      // TODO 每存儲(chǔ)一張圖片的大?。ㄗ饔糜趦?nèi)存溢出丟圖片)
      @Override
      protected int sizeOf(String key, Bitmap value) {
        //返回當(dāng)前一行所占的字節(jié)數(shù)*高度,就是圖片的大小
        return value.getRowBytes()*value.getHeight();
      }
    };//當(dāng)前圖片緩存總數(shù)的大小
  }
  /**
   * 
   * @param url 下載圖片的連接
   * @param position 需要顯示圖片的imgeView的Tag
   * @return
   */
  public Bitmap getBitmapFromUrl(String url,int position){
    //1內(nèi)存中獲取圖片LRU算法
    Bitmap bitmap=cache.get(url);
    //內(nèi)存中有指定圖片
    if (bitmap!=null) {
      Log.i("從內(nèi)存中獲得圖片", "從內(nèi)存中獲得圖片"+url);
      return bitmap;
    }
    //2文件中獲取圖片
    bitmap=getBitmapFromFile(url);
    if (bitmap!=null) {
      Log.i("從文件中獲得圖片", "從文件中獲得圖片"+url);
      return bitmap;
    }
    //3開(kāi)啟網(wǎng)絡(luò)下載
    Log.i("從網(wǎng)絡(luò)中獲得圖片", "從網(wǎng)絡(luò)中獲得圖片"+url);
    getBitmapFromNet(url,position);
    return null;

  }

  /**
   * 網(wǎng)絡(luò)獲取圖片
   * @param url 圖片的;鏈接地址
   * @param position 需要顯示的imageview的tag
   */
  private void getBitmapFromNet(String url, int position) {

    //開(kāi)啟任務(wù)
    executorService.execute(new RunnableTask(url,position));
  }
  //任務(wù)接口
  class RunnableTask implements Runnable{
    String imageUrl;
    int position;
    private HttpURLConnection httpURLConnection;
    public RunnableTask(String imageUrl, int position) {
      this.position=position;
      this.imageUrl=imageUrl;
    }

    @Override
    public void run() {
      //子線程的操作,開(kāi)啟網(wǎng)絡(luò)下載圖片
      try {
        URL url=new URL(imageUrl);
        //請(qǐng)求對(duì)象
         httpURLConnection=(HttpURLConnection) url.openConnection();
        //網(wǎng)絡(luò)請(qǐng)求的方式
        httpURLConnection.setRequestMethod("GET");
        //超時(shí)的時(shí)間,
        httpURLConnection.setConnectTimeout(5000);
        //讀取超時(shí)的時(shí)間
        httpURLConnection.setReadTimeout(5000);
        //httpURLConnection.getResponseCode()拿到最新數(shù)據(jù)
        if (httpURLConnection.getResponseCode()==200) {
          //success get data from net;get tape 
          InputStream inputStream=httpURLConnection.getInputStream();
          //將流轉(zhuǎn)化成bitmap圖片
          Bitmap bitmap=BitmapFactory.decodeStream(inputStream);
          //利用handler機(jī)制放入主線程中顯示
          Message msg=new Message();
          //需要在主線程中顯示的圖片msg.obj
          msg.obj=bitmap;
          msg.arg1=position;
          //為msg設(shè)置標(biāo)記
          msg.what=SUCCSEE;
          handler.sendMessage(msg);
          //一,將下載完后的圖片保存到內(nèi)存中
          cache.put(imageUrl, bitmap);
          //二,將下載完后的圖片保存到文件中
          writeToLoce(imageUrl,bitmap);
          return;
        }


      } catch (Exception e) {
        e.printStackTrace();
      }
      //關(guān)閉請(qǐng)求
      finally{
        //斷開(kāi)服務(wù)器
        if (httpURLConnection!=null) {
          httpURLConnection.disconnect();
        }        
      }
      //發(fā)送一個(gè)空消息
      handler.obtainMessage(FAIL).sendToTarget();
    }
  }
  /**
   * 圖片寫入cache文件夾下面的操作
   * @param imageUrl
   * @param bitmap
   */
  private void writeToLoce(String imageUrl, Bitmap bitmap) {
    try {
      String bitmapefilename=MD5Encoder.encode(imageUrl).substring(10);
      Log.i("bitmapefilename", bitmapefilename);
      File file=new File(cacheDir, bitmapefilename);
      FileOutputStream fileOutputStream =new FileOutputStream(file);
      //寫入文件的操作(1圖片類型2圖片質(zhì)量當(dāng)為100時(shí)表示不壓縮3文件流)
      bitmap.compress(CompressFormat.JPEG, 100, fileOutputStream);
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  /**
   * 讀取文件中圖片的操作
   * @param url 圖片的連接地址
   * @return
   */
  private Bitmap getBitmapFromFile(String url) {
    try {
      //使用Md5工具加密截取前10個(gè)字符串
      String bitmapefilename=MD5Encoder.encode(url).substring(10);
      /**
       * 在cache文件夾下面找到指定文件
       * dir cache文件存儲(chǔ)路徑
       * name 文件名稱
       */
      File file=new File(cacheDir, bitmapefilename);
    // file.mkdir();
      //FileInputStream fileInputStream=new FileInputStream(file);
      Bitmap bitmap=BitmapFactory.decodeFile(file.getPath());//完整文件路徑
      //Log.i("文件路徑", file.getPath().toString());
      //2讀取之后放入內(nèi)存,提高效率
      cache.put(url, bitmap);
      return bitmap;
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;

  }
}

下面就是一個(gè)使用demo了,其實(shí)很簡(jiǎn)單


package com.example.do0me;
import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.security.PublicKey; import java.util.ArrayList; import java.util.List; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import org.ksoap2.SoapEnvelope; import org.ksoap2.serialization.MarshalBase64; import org.ksoap2.serialization.SoapObject; import org.ksoap2.serialization.SoapSerializationEnvelope; import org.ksoap2.transport.HttpTransportSE; import org.xmlpull.v1.XmlPullParserException; import android.annotation.SuppressLint; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.drawable.BitmapDrawable; import android.os.Bundle; import android.os.Handler; import android.util.Base64; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.view.ViewTreeObserver.OnPreDrawListener; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.ImageView; import android.widget.ListView; import android.widget.Toast; import com.example.util.AgbcApi; import com.example.util.ClippingPicture; import com.example.util.FastBlur; import com.example.util.ImageCachceUitl; import com.tencent.connect.avatar.c; /** * 圖片三級(jí)緩存的測(cè)試+圖片上傳 * @author double 江 * */ public class MainActivity4 extends Activity { private ImageCachceUitl imageCachceUitl; private List<String> urlList=new ArrayList<String>(); private Runnable runnable; private Handler handler =new Handler(){ public void handleMessage(android.os.Message msg) { switch (msg.what) { case ImageCachceUitl.SUCCSEE: Bitmap bitmap=(Bitmap) msg.obj; int psition=msg.arg1; //通過(guò)TAg加載當(dāng)前的limageview ImageView imageView=(ImageView) listview.findViewWithTag(psition); if (null!=bitmap&&null!=imageView) { imageView.setImageBitmap(bitmap); } break; case ImageCachceUitl.FAIL: Toast.makeText(getApplicationContext(), "下載錯(cuò)誤", Toast.LENGTH_LONG).show(); default: break; } }; }; private ListView listview; private SoapObject request; private ExecutorService executorService; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main4); listview=(ListView) findViewById(R.id.imageviewlist); imageCachceUitl=new ImageCachceUitl(getApplicationContext(), handler); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg");urlList.add("http://ww4.sinaimg.cn/large/90bd89ffjw1eqvmd6o8r6j20go0p5ju2.jpg"); listview.setAdapter(new myListAdapt()); executorService=Executors.newFixedThreadPool(5); executorService.execute(new Runnable() { @Override public void run() { getImageromSdk(); } }); } public String getImageFromAndroid(String arg0,String arg1, String arg2){ Log.i("進(jìn)入端口方法", "進(jìn)入端口方法"); final String methodName="getImageFromAndroid"; final String soapAction=AgbcApi.NAMESPACE+methodName; request = new SoapObject(AgbcApi.NAMESPACE, methodName); request.addProperty("arg0",arg1); request.addProperty("arg1",arg2); SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); (new MarshalBase64()).register(envelope); envelope.bodyOut = request; envelope.dotNet=false; envelope.setOutputSoapObject(request); HttpTransportSE ht = new HttpTransportSE(AgbcApi.TASKSERVICEURL); ht.debug=true; try { ht.call(soapAction, envelope); Log.i("請(qǐng)求", envelope.bodyIn.toString()); } catch (IOException | XmlPullParserException e) { e.printStackTrace(); } return arg1; }; @SuppressLint("SdCardPath") public void getImageromSdk(){ Log.i("進(jìn)入獲取圖片方法", "進(jìn)入獲取圖片方法"); try{ String srcUrl = "/sdcard/"; //路徑 String fileName = "1.png"; //文件名 String filrName2="2.jpg"; List<String>imageList=new ArrayList<>(); imageList.add(fileName); imageList.add(filrName2); for (int i = 0; i < imageList.size(); i++) { FileInputStream fis = new FileInputStream(srcUrl + imageList.get(i)); ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buffer = new byte[4096]; int count = 0; while((count = fis.read(buffer)) >= 0){ baos.write(buffer, 0, count); } String uploadBuffer = new String(Base64.encode(baos.toByteArray(), Base64.DEFAULT)); //進(jìn)行Base64編碼 String methodName = "uploadImage"; getImageFromAndroid(methodName,imageList.get(i), uploadBuffer); //調(diào)用webservice Log.i("connectWebService", "start"); fis.close(); } }catch(Exception e){ e.printStackTrace(); } } class myListAdapt extends BaseAdapter{ private LayoutInflater layoutInflater; ImageView list_imag; Button list_but; @Override public int getCount() { // TODO Auto-generated method stub return urlList.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return urlList.get(position); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @SuppressLint({ "InflateParams", "ViewHolder" }) @Override public View getView(final int position, View convertView, ViewGroup parent) { layoutInflater=LayoutInflater.from(getApplication()); //if (layoutInflater==null) { convertView = layoutInflater.inflate(R.layout.image_list_item, null); // } list_but=(Button) convertView.findViewById(R.id.list_but); list_imag=(ImageView) convertView.findViewById(R.id.list_imag); list_imag.setTag(position); final Bitmap bitmap=imageCachceUitl.getBitmapFromUrl(urlList.get(position), position); if (null!=bitmap) { list_imag.setImageBitmap(bitmap); } list_imag.setVisibility(View.VISIBLE); list_but.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { //urlList.get(position); Log.i("獲取點(diǎn)擊焦點(diǎn)", "獲取點(diǎn)擊焦點(diǎn)"); // getImageromSdk(); //startRun(); new Thread(new Runnable() { @Override public void run() { getImageromSdk(); } }).start(); } }); return convertView; } } }

就為大家介紹到這吧,大家慢慢消化,希望文章對(duì)大家有或多或少的幫助。

相關(guān)文章

最新評(píng)論