使用viewpager + imageview時出現內存不足錯誤，即使使用高速緩存和asynctask

Question

請問有人在viewpager中添加了很多圖像嗎？ 我有一個活動，調用片段類來創建包含圖像的片段到viewpager中，並且此片段類包含緩存圖像的方法，如果圖像尚不存在於緩存中並調整圖像大小並讓drawable在asynctask減少前端任務的時間消耗... 但用所有這些方法來消除內存不足的錯誤我仍然有這個錯誤！已經兩三天了，現在正在嘗試不同的方法，而且它們都沒有工作......所以請任何想法！

我的代碼是：

import java.lang.ref.WeakReference; 

import android.content.res.Resources; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.drawable.BitmapDrawable; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.util.LruCache; 
import android.util.DisplayMetrics; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ImageView; 


public class ScreenSlidePageFragment extends Fragment { 
    /** 
    * The argument key for the page number this fragment represents. 
    */ 
    public static final String ARG_PAGE = "page"; 
    private LruCache<String, Bitmap> mMemoryCache; 

    /** 
    * The fragment's page number, which is set to the argument value for {@link #ARG_PAGE}. 
    */ 
    ImageView img; 
    int height; 
    int width; 
    private int mPageNumber; 
    private int[] pics = {R.drawable.intro1, R.drawable.intro2,R.drawable.intro3,R.drawable.intro4,R.drawable.intro5,R.drawable.intro6,R.drawable.intro7,R.drawable.intro8, 
      R.drawable.intro9,R.drawable.intro10,R.drawable.intro11,R.drawable.intro12,R.drawable.intro13,R.drawable.intro14,R.drawable.intro15,R.drawable.intro16,R.drawable.intro17,R.drawable.intro18, 
      R.drawable.intro19,R.drawable.intro20,R.drawable.intro21,R.drawable.intro22,R.drawable.intro23,R.drawable.intro24,R.drawable.intro25,R.drawable.intro26,R.drawable.intro27,R.drawable.intro28,R.drawable.intro29,R.drawable.intro30, 
      R.drawable.intro31,R.drawable.intro32,R.drawable.intro33,R.drawable.intro34,R.drawable.intro35,R.drawable.intro36,R.drawable.intro37,R.drawable.intro38,R.drawable.intro39,R.drawable.intro40,R.drawable.intro41,R.drawable.intro42, 
      R.drawable.intro43,R.drawable.intro44,R.drawable.intro45,R.drawable.intro46,R.drawable.intro47,R.drawable.intro48,R.drawable.intro49,R.drawable.intro50,R.drawable.intro51,R.drawable.intro52,R.drawable.intro53,R.drawable.intro54, 
      R.drawable.intro55,R.drawable.intro56,R.drawable.intro57,R.drawable.intro58,R.drawable.intro59,R.drawable.intro60,R.drawable.intro61,R.drawable.intro62,R.drawable.intro63,R.drawable.intro64,R.drawable.intro65,R.drawable.intro66, 
      R.drawable.intro67,R.drawable.intro68,R.drawable.intro69,R.drawable.intro70,R.drawable.intro71,R.drawable.intro72,R.drawable.intro73}; 
    int count=72;//it's the number of the images-1; 


    /** 
    * Factory method for this fragment class. Constructs a new fragment for the given page number. 
    */ 
    public static ScreenSlidePageFragment create(int pageNumber) { 
     ScreenSlidePageFragment fragment = new ScreenSlidePageFragment(); 
     Bundle args = new Bundle(); 
     args.putInt(ARG_PAGE, pageNumber); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    public ScreenSlidePageFragment() { 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
    // Get max available VM memory, exceeding this amount will throw an 
     // OutOfMemory exception. Stored in kilobytes as LruCache takes an 
     // int in its constructor. 
     DisplayMetrics displaymetrics = new DisplayMetrics(); 
     getActivity().getWindowManager().getDefaultDisplay().getMetrics(displaymetrics); 
     height = displaymetrics.heightPixels; 
     width = displaymetrics.widthPixels; 
     final int maxMemory = (int) (Runtime.getRuntime().maxMemory()/1024); 

     // Use 1/8th of the available memory for this memory cache. 
     final int cacheSize = maxMemory/8; 

     mMemoryCache = new LruCache<String, Bitmap>(cacheSize) { 
      @Override 
      protected int sizeOf(String key, Bitmap bitmap) { 
       // The cache size will be measured in kilobytes rather than 
       // number of items. 
       return bitmap.getRowBytes()*bitmap.getHeight()/1024; 
      } 
     }; 

     mPageNumber = getArguments().getInt(ARG_PAGE); 
    } 

    public void addBitmapToMemoryCache(String key, Bitmap bitmap) { 
     if (getBitmapFromMemCache(key) == null) { 
      mMemoryCache.put(key, bitmap); 
     } 
    } 

    public Bitmap getBitmapFromMemCache(String key) { 
     return mMemoryCache.get(key); 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
     Bundle savedInstanceState) {  
    ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.image_view_layout, container, false); 
    img=(ImageView) rootView.findViewById(R.id.img_pager); 
    final String imageKey = String.valueOf(pics[count-mPageNumber]); 
    final Bitmap bitmap = getBitmapFromMemCache(imageKey); 
      if (bitmap != null) { 
        img.setImageBitmap(bitmap); 
       } else { 
        img.setImageResource(pics[count-mPageNumber]); 
        BitmapWorkerTask task = new BitmapWorkerTask(img); 
        task.execute(pics[count-mPageNumber]); 
       } 
     return rootView; 
    } 




    @Override 
    public void onDetach(){ 
     super.onDetach(); 
     super.onDetach(); 
     Bitmap bitmap = ((BitmapDrawable)img.getDrawable()).getBitmap(); 
     bitmap.recycle();  
     //FragmentManager fragmentManager = getFragmentManager(); 
     //FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); 
     //fragmentTransaction.remove(this).commit(); 
    } 


    /** 
    * Returns the page number represented by this fragment object. 
    */ 
    public int getPageNumber() { 
     return mPageNumber; 
    } 

    class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> { 
     private final WeakReference<ImageView> imageViewReference; 

     public BitmapWorkerTask(ImageView imageView) { 
      // Use a WeakReference to ensure the ImageView can be garbage collected 
      imageViewReference = new WeakReference<ImageView>(imageView); 
     } 

     // Decode image in background. 
     @Override 
     protected Bitmap doInBackground(Integer... params) { 
      final Bitmap bitmap = decodeSampledBitmapFromResource(getResources(), params[0],width,height); 
      addBitmapToMemoryCache(String.valueOf(params[0]), bitmap); 
      return bitmap; 
     } 

     // Once complete, see if ImageView is still around and set bitmap. 
     @Override 
     protected void onPostExecute(Bitmap bitmap) { 
      if (imageViewReference != null && bitmap != null) { 
       final ImageView imageView = imageViewReference.get(); 
       if (imageView != null) { 
        imageView.setImageBitmap(bitmap); 
       } 
      } 
     } 
    } 

    public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, 
      int reqWidth, int reqHeight) { 

     // First decode with inJustDecodeBounds=true to check dimensions 
     final BitmapFactory.Options options = new BitmapFactory.Options(); 
     options.inJustDecodeBounds = true; 
     BitmapFactory.decodeResource(res, resId, options); 

     // Calculate inSampleSize 
     options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); 

     // Decode bitmap with inSampleSize set 
     options.inJustDecodeBounds = false; 
     return BitmapFactory.decodeResource(res, resId, options); 
    } 


    public static int calculateInSampleSize(
      BitmapFactory.Options options, int reqWidth, int reqHeight) { 
    // Raw height and width of image 
    final int height = options.outHeight; 
    final int width = options.outWidth; 
    int inSampleSize = 1; 

    if (height > reqHeight || width > reqWidth) { 

     // Calculate ratios of height and width to requested height and width 
     final int heightRatio = Math.round((float) height/(float) reqHeight); 
     final int widthRatio = Math.round((float) width/(float) reqWidth); 

     // Choose the smallest ratio as inSampleSize value, this will guarantee 
     // a final image with both dimensions larger than or equal to the 
     // requested height and width. 
     inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; 
    } 

    return inSampleSize; 
} 

} 

和活動是：

import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentStatePagerAdapter; 
import android.support.v4.view.PagerAdapter; 
import android.support.v4.view.ViewPager; 
import android.view.Menu; 



public class Introduction_Activity extends FragmentActivity { 
    private static final int NUM_PAGES = 73; 

    private ViewPager mPager; 

    /** 
    * The pager adapter, which provides the pages to the view pager widget. 
    */ 
    private PagerAdapter mPagerAdapter; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_introduction); 


     // Instantiate a ViewPager and a PagerAdapter. 
     mPager = (ViewPager) findViewById(R.id.imgs_viewpager); 
     mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager()); 
     mPager.setAdapter(mPagerAdapter); 
     mPager.setCurrentItem(NUM_PAGES-1,false);  
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.introduction_, menu); 
     return true; 
    } 



    private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter { 
     public ScreenSlidePagerAdapter(FragmentManager fm) { 
      super(fm); 
     } 

     @Override 
     public Fragment getItem(int position) { 

      return ScreenSlidePageFragment.create(position); 

      } 

     @Override 
     public int getCount() { 
      return NUM_PAGES; 
     } 


    } 


} 

問題：

10-02 06:21:48.230: E/dalvikvm-heap(8944): Out of memory on a 7071376-byte allocation. 
10-02 06:21:48.245: E/AndroidRuntime(8944): FATAL EXCEPTION: AsyncTask #4 
10-02 06:21:48.245: E/AndroidRuntime(8944): java.lang.RuntimeException: An error occured while executing doInBackground() 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.os.AsyncTask$3.done(AsyncTask.java:278) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.lang.Thread.run(Thread.java:856) 
10-02 06:21:48.245: E/AndroidRuntime(8944): Caused by: java.lang.OutOfMemoryError 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.Bitmap.nativeCreate(Native Method) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.Bitmap.createBitmap(Bitmap.java:605) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.Bitmap.createBitmap(Bitmap.java:551) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:437) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.BitmapFactory.finishDecode(BitmapFactory.java:618) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:593) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:445) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.graphics.BitmapFactory.decodeResource(BitmapFactory.java:468) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at packagename.ScreenSlidePageFragment.decodeSampledBitmapFromResource(ScreenSlidePageFragment.java:178) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at packagename.ScreenSlidePageFragment$BitmapWorkerTask.doInBackground(ScreenSlidePageFragment.java:148) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at packagename.ScreenSlidePageFragment$BitmapWorkerTask.doInBackground(ScreenSlidePageFragment.java:1) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at android.os.AsyncTask$2.call(AsyncTask.java:264) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 
10-02 06:21:48.245: E/AndroidRuntime(8944):  ... 5 more 

Answer 1

試試這個

添加以下內容的應用程序標籤在你的清單

android:largeHeap="true" 

希望它能幫助你。

Answer 2

AQUIRE一大堆清單中使用這樣的：

android:largeHeap="true" 

，幾乎所有的問題的解決方案都存在對有關內存溢出錯誤，這些鏈接：

meomry-out-of-error

Memory Leak and Out of memory Error using List,LinkedList and HashMap

Memory Leak and Out of memory Error using LRU Cache

Memory Leak and Out of memory Error using Disk LRU Cache

Answer 3

android:largeHeap="true" 

這不是一個很好的解決方案。您正在使用largeHeap，但是從Android 3.0中添加了此標記，並且大堆的大小是原始堆的兩倍。這僅僅意味着它可能有如此多的數字取決於設備製造商。

你應該想出一個解決方案來處理所有類型設備的內存不足錯誤。像這樣的解決方案可以在某些設備上工作，但不能保證它可以在任何地方工作。我想說的是，你可能會得到一個很小的堆，它仍然小於你的要求。

LruCache不知道您剛剛描述的內容。通過文件，

A cache that holds strong references to a limited number of values. Each time a value is accessed, it is moved to the head of a queue. When a value is added to a full cache, the value at the end of that queue is evicted and may become eligible for garbage collection. 

它舉行強烈的參考。

所以做到以下幾點，

• 優化圖像。根據設備顯示器 分辨率調整圖像分辨率。如果您必須顯示非常高分辨率的圖像，請確保在任何給定時刻只有圖像可見圖像在內存中。
• 而不是強大的參考使用周參考，並保持在 記憶。

Answer 4

我面臨同樣的問題，解決了它，如下

最佳實施例中機器人的開發人員指南中給出，遵循步驟此導向臺階。

1. 實施inJustDecodeBounds http://developer.android.com/training/displaying-bitmaps/load-bitmap.html

2. 按照下面的指南異步和緩存，您還可以從同一個鏈接樣品。 http://developer.android.com/training/displaying-bitmaps/display-bitmap.html

Answer 5

，我學到了艱辛的道路的教訓是：「不要重新發明輪子」。使用第三方庫如Picasso,Fresco，Glide等來擺脫這種情況。另外的富礦是你的代碼是可維護的。

Answer 6

對於加載圖像使用滑翔圖片庫 https://developer.android.com/topic/performance/graphics/index.html

在片段onDestory方法使每一個視圖和對象爲空;