3

请问有人之前在viewpager中添加了很多imageviews吗？我有一个活动，它调用片段类以将包含图像的片段创建到视图页面中，并且该片段类包含缓存图像的方法，如果它不存在于缓存内存中并调整图像大小并让可绘制对象在异步任务中执行减少前端任务的时间消耗......但是用所有这些方法来消除内存不足错误我仍然有这个错误！已经两三天了，现在尝试了不同的方法，但都没有奏效……所以请大家多多思考！！

我的代码是：

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;
}

}

活动是：

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;
        }


    }


}

问题：

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
4

7 回答 7

8

试试这个

将以下内容添加到清单中的应用程序标记中

android:largeHeap="true"

希望它会帮助你。

于 2013-10-02T06:39:25.483 回答
4 
android:largeHeap="true"

这不是一个好的解决方案。您正在使用 largeHeap 但这个标签是从 Android 3.0 添加的，并且大堆的大小是原始堆的两倍。这仅仅意味着它可能有很多数字取决于设备制造商。

您应该想出一个解决方案来处理所有类型设备的内存不足错误。像这样的解决方案可以在某些设备上运行，但不能保证它可以在任何地方运行。我想说的是，您最终可能会拥有一个比您的要求还小的堆。

LruCache不知道你刚才描述的。通过文档，

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.

它具有很强的参考价值。

因此，请执行以下操作，

  • 优化图像。根据设备显示分辨率调整图像分辨率。如果您必须显示非常高分辨率的图像，请确保在任何给定时刻只有图像可见图像在内存中。
  • 而不是强参考使用周参考并在内存中保持这种方式。
于 2013-10-03T05:34:11.897 回答
2

我遇到了同样的问题并解决了，如下

最佳示例在 android 开发者指南中给出，请按照本指南逐步操作。

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

  2. 请遵循以下异步和缓存指南，您也可以从同一链接下载示例。 http://developer.android.com/training/displaying-bitmaps/display-bitmap.html

于 2014-01-08T09:41:42.207 回答
0

在清单中使用它来获取大堆：

android:largeHeap="true"

几乎所有的问题解决方案都出现在这些与内存不足相关的链接上：

错误记忆

使用 List、LinkedList 和 HashMap 的内存泄漏和内存不足错误

使用 LRU 缓存的内存泄漏和内存不足错误

使用磁盘 LRU 缓存的内存泄漏和内存不足错误

于 2013-10-02T07:00:06.383 回答
0

我从艰难中学到的教训是，“不要重新发明轮子”。使用Picasso、Fresco、Glide等第三方库来摆脱这种情况。额外的好处是你的代码很容易维护。

于 2016-12-18T17:33:30.343 回答
0

加载图像使用 Glide Image library https://developer.android.com/topic/performance/graphics/index.html

在片段 onDestory 方法中，使每个视图和对象都为空；

于 2017-05-25T10:06:32.973 回答
0

第 1 步：在清单文件中

android:largeHeap="true"

第2步

viewpager.offscreenPageLimit = 2 //kotlin 
viewpaget.setOffscreenPageLimit(2) //java

并查看此处以分析您的应用程序内存使用情况

https://developer.android.com/studio/profile/android-profiler

于 2020-10-10T03:32:38.593 回答