我使用Fedor的代码(https://github.com/thest1/LazyList)来加载位图.根据我的要求,我修改了几行代码.当堆内存超过阈值时,我出现内存不足错误.在同一主题上发布了各种问题.大多数人建议使用SoftReference和bitmap recycle().我正在使用SoftReference,但我仍面临问题.而且我也很困惑在哪里使用位图循环方法.

MemoryCache.java

public class MemoryCache {

private static final String TAG = "MemoryCache";
private static Map<String, SoftReference<Bitmap>> cache=Collections.synchronizedMap(
        new LinkedHashMap<String, SoftReference<Bitmap>>(16,0.75f,false));//Last argument true for LRU ordering
private long size=0;//current allocated size
private long limit=30000000;//max memory in bytes

public MemoryCache(){

    long cacheSize = Runtime.getRuntime().maxMemory();
    setLimit(cacheSize);
}

public void setLimit(long new_limit){
    limit=new_limit;

}

public Bitmap get(String id){
    try{
        if(!cache.containsKey(id))
            return null;
        //NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
        return cache.get(id).get();
    }catch(NullPointerException ex){
        ex.printStackTrace();
        return null;
    }
}

public void put(String id, Bitmap bitmap){ …

我在我的活动中修改以下代码:

new Handler().postDelayed(new Runnable() {
 public void run() {
    txtStatus.setText("hello");
  }
}, 1000);

至:

static Runnable myRunnable = new Runnable() {
public void run() {
   txtStatus.setText("hello");
};

new Handler().postDelayed(myRunnable, 1000);

这显然不起作用,因为我们引用了一个非静态变量.

这也不起作用:

public void setText() {
  txtStatus.setText("hello");
}
static Runnable myRunnable = new Runnable() {
public void run() {
   setText(); // doesn't work
   MyActivity.this.setText(); // still doesn't work

};

new Handler().postDelayed(myRunnable, 1000);

那么我的初始示例如何被重写为使用静态类而不是匿名内部类(以避免内存泄漏的可能性)？

当我多次启动和退出我的应用程序时,其RAM使用量增加超过500 MB.当我检查内存转储使用adb shell dumpsys meminfo 我检查未知pss value是问题的原因.什么是大pss值的原因以及如何降低pss值.

Shared  Private     Heap     Heap     Heap

                   Pss    Dirty    Dirty     Size    Alloc     Free

                ------   ------   ------   ------   ------   ------

       Native        0        0        0   534460   531827     1604
       Dalvik    51013    17868    50664    90480    82266     8214
       Cursor        0        0        0                           
       Ashmem        0        0        0                           
    Other dev    14292       52    14288                           
     .so mmap     3810     2320     1720                           
    .jar mmap        0        0        0                           
    .apk mmap     1305        0        0                           
    .ttf mmap        0        0        0                           
    .dex mmap     2960        0 …

运行我的应用程序时，我一直收到此错误。该应用程序可以正常编译，一旦我开始与它进行交互（ImageSlider），有时它会崩溃并显示该消息。

LogCat

    02-18 12:25:05.426: E/AndroidRuntime(4545): FATAL EXCEPTION: main
02-18 12:25:05.426: E/AndroidRuntime(4545): java.lang.OutOfMemoryError
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:493)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:299)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at com.oneplc.viessmannapp.imageslider.adapter.FullScreenImageAdapter.instantiateItem(FullScreenImageAdapter.java:59)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:832)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager.populate(ViewPager.java:1016)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager$3.run(ViewPager.java:244)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager.completeScroll(ViewPager.java:1761)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.support.v4.view.ViewPager.onInterceptTouchEvent(ViewPager.java:1894)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1629)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957)
02-18 12:25:05.426: E/AndroidRuntime(4545):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1684)
02-18 12:25:05.426: …

我真的很高兴我将长期运行的任务切换到了协程，这些任务不断产生UI 线程的结果。与 Android 中的 AsyncTask 或常规线程相比，它提高了性能并将内存使用量减少了 3 倍，并且所有内存泄漏都消失了。

    lateinit var initEngineJob: Job
    override val coroutineContext: CoroutineContext
        get() = initEngineJob + Dispatchers.Main

fun initWorkEngineCoroutine()
    {
        launch {

            while(true) {
                val deferred = async(Dispatchers.Default) {
                    getResultsFromEngine()
                }
                    val result = deferred.await()
                    if (result != null) {
                    //UI thread
                        draw!!.showResult(result)
                    }
                }
            }

        }

fun getResultsFromEngine() :Result? {
           result = // some results from native c++ engine, …