Android圖片快取技術 直接用在你的專案中,簡單方便高效
阿新 • • 發佈:2019-01-13
好久沒有寫部落格了,最近比較繁瑣,什麼面試呀,找工作呀,大三的生活就快完了,準確的是大學的生活就快完了!三年了,一直在搞移動開發,感覺好快呀,不想就這樣的離開學校了!咳咳咳,扯遠了。。。 前不久搞的Android圖片快取,剛開始引入開源的框架,用著還行,但是在開發中遇到問題,就比如universal-image-loader-1.9.5.jar這個框架吧,在載入圖片的時候自定義imageview無法載入,可能是存在以下問題吧,況且匯入框架導致開發的專案包越來越大,基於上面的這幾種情況,於是我就想自己寫一個圖片三級快取的工具。
簡要分析
這是第一次加載出來的圖片,當然是網上的一張圖片:
圖片加載出來了,我們要看看日誌,日誌不會說謊,我截圖的日誌
剛才是本地和記憶體都沒有那就的去網路下載了,所有日誌列印的是開啟網路下載
然而第二次進入應用的時候呢?還回去開啟網路下載嗎?那肯定不會的,要不這樣要它有啥用呢?
看看吧這就是第二次進入應用的時候的日誌
好的,這麼好的圖片三級快取,那到底怎麼實現的呢以及到底怎麼用的呢?下面就貼出我寫的程式碼吧!讓小夥伴看看,順便優化優化!
好了,
`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;/** * 圖片的三級快取工具類{日後專案需要} * @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演算法集合,string是圖片的url,bitmap為圖片的值型別 private File cacheDir; Handler handler; private ExecutorService executorService;//維護線性池 public ImageCachceUitl(Context context ,Handler handler){ this.context=context; this.handler=handler; cacheDir=context.getCacheDir();//獲得cache資料夾 //維護幾個網路執行緒下載圖片 executorService=Executors.newFixedThreadPool(5); int maxSize=(int) (Runtime.getRuntime().maxMemory()/8);//獲得執行環境的記憶體大小的1/8 cache=new LruCache<String, Bitmap>(maxSize){ // TODO 每儲存一張圖片的大小(作用於記憶體溢位丟圖片) @Override protected int sizeOf(String key, Bitmap value) { //返回當前一行所佔的位元組數*高度,就是圖片的大小 return value.getRowBytes()*value.getHeight(); } };//當前圖片快取總數的大小 } /** * * @param url 下載圖片的連線 * @param position 需要顯示圖片的imgeView的Tag * @return */ public Bitmap getBitmapFromUrl(String url,int position){ //1記憶體中獲取圖片LRU演算法 Bitmap bitmap=cache.get(url); //記憶體中有指定圖片 if (bitmap!=null) { Log.i("從記憶體中獲得圖片", "從記憶體中獲得圖片"+url); return bitmap; } //2檔案中獲取圖片 bitmap=getBitmapFromFile(url); if (bitmap!=null) { Log.i("從檔案中獲得圖片", "從檔案中獲得圖片"+url); return bitmap; } //3開啟網路下載 Log.i("從網路中獲得圖片", "從網路中獲得圖片"+url); getBitmapFromNet(url,position); return null; } /** * 網路獲取圖片 * @param url 圖片的;連結地址 * @param position 需要顯示的imageview的tag */ private void getBitmapFromNet(String url, int position) { //開啟任務 executorService.execute(new RunnableTask(url,position)); } //任務介面 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() { //子執行緒的操作,開啟網路下載圖片 try { URL url=new URL(imageUrl); //請求物件 httpURLConnection=(HttpURLConnection) url.openConnection(); //網路請求的方式 httpURLConnection.setRequestMethod("GET"); //超時的時間, httpURLConnection.setConnectTimeout(5000); //讀取超時的時間 httpURLConnection.setReadTimeout(5000); //httpURLConnection.getResponseCode()拿到最新資料 if (httpURLConnection.getResponseCode()==200) { //success get data from net;get tape InputStream inputStream=httpURLConnection.getInputStream(); //將流轉化成bitmap圖片 Bitmap bitmap=BitmapFactory.decodeStream(inputStream); //利用handler機制放入主執行緒中顯示 Message msg=new Message(); //需要在主執行緒中顯示的圖片msg.obj msg.obj=bitmap; msg.arg1=position; //為msg設定標記 msg.what=SUCCSEE; handler.sendMessage(msg); //一,將下載完後的圖片儲存到記憶體中 cache.put(imageUrl, bitmap); //二,將下載完後的圖片儲存到檔案中 writeToLoce(imageUrl,bitmap); return; } } catch (Exception e) { e.printStackTrace(); } //關閉請求 finally{ //斷開伺服器 if (httpURLConnection!=null) { httpURLConnection.disconnect(); } } //傳送一個空訊息 handler.obtainMessage(FAIL).sendToTarget(); } } /** * 圖片寫入cache資料夾下面的操作 * @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); //寫入檔案的操作(1圖片型別2圖片質量當為100時表示不壓縮3檔案流) bitmap.compress(CompressFormat.JPEG, 100, fileOutputStream); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 讀取檔案中圖片的操作 * @param url 圖片的連線地址 * @return */ private Bitmap getBitmapFromFile(String url) { try { //使用Md5工具加密擷取前10個字串 String bitmapefilename=MD5Encoder.encode(url).substring(10); /** * 在cache資料夾下面找到指定檔案 * dir cache檔案儲存路徑 * name 檔名稱 */ File file=new File(cacheDir, bitmapefilename); // file.mkdir(); //FileInputStream fileInputStream=new FileInputStream(file); Bitmap bitmap=BitmapFactory.decodeFile(file.getPath());//完整檔案路徑 //Log.i("檔案路徑", file.getPath().toString()); //2讀取之後放入記憶體,提高效率 cache.put(url, bitmap); return bitmap; } catch (Exception e) { e.printStackTrace(); } return null; }}`下面就是一個使用demo了,其實很簡單`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;/** * 圖片三級快取的測試+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TAg載入當前的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("進入埠方法", "進入埠方法"); 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("請求", envelope.bodyIn.toString()); } catch (IOException | XmlPullParserException e) { e.printStackTrace(); } return arg1; }; @SuppressLint("SdCardPath") public void getImageromSdk(){ Log.i("進入獲取圖片方法", "進入獲取圖片方法"); try{ String srcUrl = "/sdcard/"; //路徑 String fileName = "1.png"; //檔名 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)); //進行Base64編碼 String methodName = "uploadImage"; getImageFromAndroid(methodName,imageList.get(i), uploadBuffer); //呼叫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("獲取點選焦點", "獲取點選焦點"); // getImageromSdk(); //startRun(); new Thread(new Runnable() { @Override public void run() { getImageromSdk(); } }).start(); } }); return convertView; } }}`
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
- 61
- 62
- 63
- 64
- 65
- 66
- 67
- 68
- 69
- 70
- 71
- 72
- 73
- 74
- 75
- 76
- 77
- 78
- 79
- 80
- 81
- 82
- 83
- 84
- 85
- 86
- 87
- 88
- 89
- 90
- 91
- 92
- 93
- 94
- 95
- 96
- 97
- 98
- 99
- 100
- 101
- 102
- 103
- 104
- 105
- 106
- 107
- 108
- 109
- 110
- 111
- 112
- 113
- 114
- 115
- 116
- 117
- 118
- 119
- 120
- 121
- 122
- 123
- 124
- 125
- 126
- 127
- 128
- 129
- 130
- 131
- 132
- 133
- 134
- 135
- 136
- 137
- 138
- 139
- 140
- 141
- 142
- 143
- 144
- 145
- 146
- 147
- 148
- 149
- 150
- 151
- 152
- 153
- 154
- 155
- 156
- 157
- 158
- 159
- 160
- 161
- 162
- 163
- 164
- 165
- 166
- 167
- 168
- 169
- 170
- 171
- 172
- 173
- 174
- 175
- 176
- 177
- 178
- 179
- 180
- 181
- 182
- 183
- 184
- 185
- 186
- 187
- 188
- 189
- 190
- 191
- 192
- 193
- 194
- 195
- 196
- 197
- 198
- 199
- 200
- 201
- 202
- 203
- 204
- 205
- 206
- 207
- 208
- 209
- 210
- 211
- 212
- 213
- 214
- 215
- 216
- 217
- 218
- 219
- 220
- 221
- 222
- 223
- 224
- 225
- 226
- 227
- 228
- 229
- 230
- 231
- 232
- 233
- 234
- 235
- 236
- 237
- 238
- 239
- 240
- 241
- 242
- 243
- 244
- 245
- 246
- 247
- 248
- 249
- 250
- 251
- 252
- 253
- 254
- 255
- 256
- 257
- 258
- 259
- 260
- 261
- 262
- 263
- 264
- 265
- 266
- 267
- 268
- 269
- 270
- 271
- 272
- 273
- 274
- 275
- 276
- 277
- 278
- 279
- 280
- 281
- 282
- 283
- 284
- 285
- 286
- 287
- 288
- 289
- 290
- 291
- 292
- 293
- 294
- 295
- 296
- 297
- 298
- 299
- 300
- 301
- 302
- 303
- 304
- 305
- 306
- 307
- 308
- 309
- 310
- 311
- 312
- 313
- 314
- 315
- 316
- 317
- 318
- 319
- 320
- 321
- 322
- 323
- 324
- 325
- 326
- 327
- 328
- 329
- 330
- 331
- 332
- 333
- 334
- 335
- 336
- 337
- 338
- 339
- 340
- 341
- 342
- 343
- 344
- 345
- 346
- 347
- 348
- 349
- 350
- 351
- 352
- 353
- 354
- 355
- 356
- 357
- 358
- 359
- 360
- 361
- 362
- 363
- 364
- 365
- 366
- 367
- 368
- 369
- 370
- 371
- 372
- 373
- 374
- 375
- 376
- 377
- 378
- 379
- 380
- 381
- 382
- 383
- 384
- 385
- 386
- 387
- 388
- 389
- 390
- 391
- 392
- 393
- 394
- 395
- 396
- 397
- 398
- 399
- 400
- 401
- 402
- 403
- 404
- 405
- 406
- 407
- 408
- 409
- 410
- 411
- 412
- 413
- 414
- 415
- 416
- 417
- 418
- 419
- 420
- 421
- 422
- 423
- 424
- 425
- 426
- 427
- 428
- 429
- 430
- 431
- 432
- 433
大概就是些吧!還沒有 吃飯。。。。走了去早吃飯了,不能太玩命了
再分享一下我老師大神的人工智慧教程吧。零基礎!通俗易懂!風趣幽默!還帶黃段子!希望你也加入到我們人工智慧的隊伍中來!https://blog.csdn.net/jiangjunshow