在我的应用程序中，我使用了 ListView 和列表适配器。当单击 ListView 中的某个子项时，会出现一个可单击的 TextView ，它将多个位图加载到 ScrollView 中 - 并且此 ScrollView 显示在警报对话框中。
所有这一切都发生在一个扩展 BaseExpandableListAdapter 的类中，当单击此文本链接时 - 将调用一个静态内部类，它负责加载所有这些 (9) 位图。这个内部类扩展了 asynctask。
在将这些位图加载到 ScrollView 之前 - 这个内部类的两个静态方法被调用，将位图缩小到适合屏幕的大小。这里我使用 Bitmapfactory.decoderesource 和 Bitmap.scaledownBitmap。
所有这一切都工作得很好，..但是程序存在内存泄漏。这个泄漏之前相当大，因为这个内部类是非静态的。因此，通过将此内部类设为静态来减少泄漏。是的——减少了，但没有消除。
我也对几个对象进行了弱引用，但没有成功。例如 - 我对引用内部类的对象进行了弱引用。我对传递给内部类的上下文进行了弱引用。我什至对位图做了 w weak reference。根本没有成功。
我的 Samsung Galazy s3 的堆大小是 64 MB。当 ListView 及其所有子项首次加载时，使用的堆大约为 17 MB。然后，当加载 9 个位图时，它会增加到大约 42 MB。如果我然后单击另一个子项目，使用的图像堆是相同的 - 但在继续单击并加载位图后，堆突然变大到 47 MB ... 然后相同的场景...... 静止一段时间 - 然后高达 52 MB .... 56 MB。所以我几乎必须单击并加载位图才能使内存不足。比如说 15 - 20 分钟的密集使用。
结论:使内部类静态化有助于我减少内存泄漏。但是尽管对几个对象(尤其是上下文)进行了弱引用，但我无法进一步减少泄漏。
有什么建议吗？
下面的代码有点乱....
static class BitmapWorkerTask extends AsyncTask <Integer, Void, Bitmap[]> {
private int[] data;
private int[] width, height;
private int nmbrOfImages;
private String[] scrollText;
private ImageView mImage;
private View view;
private LayoutInflater factory;
private AlertDialog.Builder alertadd;
private Context context;
private WeakReference <Context> sc;
private WeakReference <ImageView> mImageV;
private WeakReference <Bitmap[]> bitmapV;
public BitmapWorkerTask(int[] width, int[] height, int nmbrOfImages, String[] scrollText, Context context) {
this.width = width;
this.height = height;
this.nmbrOfImages = nmbrOfImages;
this.scrollText = scrollText;
this.context = context;
mImage = null;
view = null;
factory = null;
alertadd = null;
System.gc();
sc = new WeakReference <Context> (context);
try {
for (int i = 0; i < scaledBitmap.length; i++) {
scaledBitmap[i].recycle();
scaledBitmap[i] = null;
}
} catch (NullPointerException ne) {
System.out.println("nullpointerexception ... gick inte recycla bitmapbilder");
}
switch (nmbrOfImages) {
case 0:
data = new int[1];
break;
case 1:
data = new int[3];
break;
case 2:
data = new int[5];
break;
case 3:
data = new int[9];
break;
}
}
@Override
protected Bitmap[] doInBackground(Integer ... params) {
switch (nmbrOfImages) {
case 0:
data[0] = params[0];
break;
case 1:
data[0] = params[0];
data[1] = params[1];
data[2] = params[2];
break;
case 2:
data[0] = params[0];
data[1] = params[1];
data[2] = params[2];
data[3] = params[3];
data[4] = params[4];
break;
case 3:
data[0] = params[0];
data[1] = params[1];
data[2] = params[2];
data[3] = params[3];
data[4] = params[4];
data[5] = params[5];
data[6] = params[6];
data[7] = params[7];
data[8] = params[8];
break;
}
alertadd = new AlertDialog.Builder(sc.get());
factory = LayoutInflater.from(sc.get());
Bitmap[] bm = decodeSampledBitmapFromResource(sc.get().getResources(), data, width, height);
bitmapV = new WeakReference <Bitmap[]> (bm);
return bitmapV.get();
}
protected void onPostExecute(Bitmap[] bitmap) {
switch (nmbrOfImages) {
case 0:
if (view == null) {
view = factory.inflate(R.layout.alertviews, null);
}
mImage = (ImageView) view.findViewById(R.id.extra_img);
mImage.setImageBitmap(bitmap[0]);
alertadd.setView(view);
alertadd.setNeutralButton("Here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
}
});
alertadd.show();
break;
case 1:
if (view == null) {
view = factory.inflate(R.layout.alertviews2, null);
}
mImage = (ImageView) view.findViewById(R.id.img1);
mImage.setImageBitmap(bitmap[0]);
mImage = (ImageView) view.findViewById(R.id.img2);
mImage.setImageBitmap(bitmap[1]);
mImage = (ImageView) view.findViewById(R.id.img3);
mImage.setImageBitmap(bitmap[2]);
try {
TextView mText2 = (TextView) view.findViewById(R.id.text_img1_scrollview);
mText2.setText(scrollText[0]);
mText2 = (TextView) view.findViewById(R.id.text_img2_scrollview);
mText2.setText(scrollText[1]);
mText2 = (TextView) view.findViewById(R.id.text_img3_scrollview);
mText2.setText(scrollText[2]);
} catch (NullPointerException ne) {
System.out.println("nullpointerexception ... TextView i metoden onPostExecute");
}
alertadd.setView(view);
alertadd.setNeutralButton("Here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
}
});
alertadd.show();
break;
case 2:
if (view == null) {
view = factory.inflate(R.layout.alertviews3, null);
}
mImage = (ImageView) view.findViewById(R.id.img1);
mImage.setImageBitmap(bitmap[0]);
mImage = (ImageView) view.findViewById(R.id.img2);
mImage.setImageBitmap(bitmap[1]);
mImage = (ImageView) view.findViewById(R.id.img3);
mImage.setImageBitmap(bitmap[2]);
mImage = (ImageView) view.findViewById(R.id.img4);
mImage.setImageBitmap(bitmap[3]);
mImage = (ImageView) view.findViewById(R.id.img5);
mImage.setImageBitmap(bitmap[4]);
try {
TextView mText3 = (TextView) view.findViewById(R.id.text_img1_scrollview);
mText3.setText(scrollText[0]);
mText3 = (TextView) view.findViewById(R.id.text_img2_scrollview);
mText3.setText(scrollText[1]);
mText3 = (TextView) view.findViewById(R.id.text_img3_scrollview);
mText3.setText(scrollText[2]);
mText3 = (TextView) view.findViewById(R.id.text_img4_scrollview);
mText3.setText(scrollText[3]);
mText3 = (TextView) view.findViewById(R.id.text_img5_scrollview);
mText3.setText(scrollText[4]);
} catch (NullPointerException ne) {
System.out.println("nullpointerexception ... TextView i metoden onPostExecute");
}
alertadd.setView(view);
alertadd.setNeutralButton("Here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
}
});
alertadd.show();
break;
case 3:
if (view == null) {
view = factory.inflate(R.layout.alertviews4, null);
}
AlertDialog.Builder alertadd = new AlertDialog.Builder(context);
mImage = (ImageView) view.findViewById(R.id.img1);
mImage.setImageBitmap(bitmap[0]);
mImage = (ImageView) view.findViewById(R.id.img2);
mImage.setImageBitmap(bitmap[1]);
mImage = (ImageView) view.findViewById(R.id.img3);
mImage.setImageBitmap(bitmap[2]);
mImage = (ImageView) view.findViewById(R.id.img4);
mImage.setImageBitmap(bitmap[3]);
mImage = (ImageView) view.findViewById(R.id.img5);
mImage.setImageBitmap(bitmap[4]);
mImage = (ImageView) view.findViewById(R.id.img6);
mImage.setImageBitmap(bitmap[5]);
mImage = (ImageView) view.findViewById(R.id.img7);
mImage.setImageBitmap(bitmap[6]);
mImage = (ImageView) view.findViewById(R.id.img8);
mImage.setImageBitmap(bitmap[7]);
mImage = (ImageView) view.findViewById(R.id.img9);
mImage.setImageBitmap(bitmap[8]);
try {
TextView mText4 = (TextView) view.findViewById(R.id.text_img1_scrollview);
mText4.setText(scrollText[0]);
mText4 = (TextView) view.findViewById(R.id.text_img2_scrollview);
mText4.setText(scrollText[1]);
mText4 = (TextView) view.findViewById(R.id.text_img3_scrollview);
mText4.setText(scrollText[2]);
mText4 = (TextView) view.findViewById(R.id.text_img4_scrollview);
mText4.setText(scrollText[3]);
mText4 = (TextView) view.findViewById(R.id.text_img5_scrollview);
mText4.setText(scrollText[4]);
mText4 = (TextView) view.findViewById(R.id.text_img6_scrollview);
mText4.setText(scrollText[5]);
mText4 = (TextView) view.findViewById(R.id.text_img7_scrollview);
mText4.setText(scrollText[6]);
mText4 = (TextView) view.findViewById(R.id.text_img8_scrollview);
mText4.setText(scrollText[7]);
mText4 = (TextView) view.findViewById(R.id.text_img9_scrollview);
mText4.setText(scrollText[8]);
} catch (NullPointerException ne) {
System.out.println("nullpointerexception ... TextView i metoden onPostExecute");
}
alertadd.setView(view);
alertadd.setNeutralButton("Here!", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dlg, int sumthin) {
}
});
alertadd.show();
break;
}
}
/**
*
* @param options
* @param reqW
* @param reqH
* @return
*/
public static int calculateInSampleSize(BitmapFactory.Options options, int reqW, int reqH) {
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
int inSampleSize = 1;
if (imageHeight > reqH || imageWidth > reqW) {
int heightRatio = Math.round((float) imageHeight / (float) reqH);
int widthRatio = Math.round((float) imageWidth / (float) reqW);
inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
System.out.println("i if-satsen!");
System.out.println("height-ratio: " + heightRatio + "\nwidth-ratio: " + widthRatio);
}
System.out.println("samplesize: " + inSampleSize);
inSampleSize = inSampleSize;
return inSampleSize;
}
@SuppressLint("NewApi")
/**
*
* @param res
* @param resId
* @param reqW
* @param reqH
* @return
*/
public static Bitmap[] decodeSampledBitmapFromResource(Resources res, int[] resId, int[] reqW, int[] reqH) {
scaledBitmap = new Bitmap[resId.length];
BitmapFactory.Options options;
for (int i = 0; i < resId.length; i++) {
options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
Bitmap bm =BitmapFactory.decodeResource(res, resId[i], options);
System.out.println("ursprunglig bild: h = " + options.outHeight + " w = " + options.outWidth);
options.inSampleSize = calculateInSampleSize(options, reqW[i], reqH[i]);
while (options.outHeight < reqH[i] || options.outWidth < reqW[i]) {
options.inSampleSize--;
System.out.println("räknar nu ner insampleseize\ninSamleSize =" + options.inSampleSize);
}
options.inJustDecodeBounds = false;
bm = BitmapFactory.decodeResource(res, resId[i], options);
System.out.println("innan omskalning: h = " + options.outHeight + " w = " + options.outWidth);
System.out.println("antalet bytes: " + bm.getByteCount());
System.out.println("native free size: " + Debug.getNativeHeapFreeSize() );
scaledBitmap[i] = Bitmap.createScaledBitmap(bm, reqW[i], reqH[i], true);
bm.recycle();
bm = null;
}
System.gc();
WeakReference <Bitmap[] > sc = new WeakReference <Bitmap[]> (scaledBitmap);
return sc.get();
}
}
最佳答案
您保持对位图的双重引用 曾经很弱，曾经是硬拷贝 你的问题代码是:
Bitmap[] bm = decodeSampledBitmapFromResource(sc.get().getResources(), data, width, height);
bitmapV = new WeakReference <Bitmap[]> (bm);
你没有去掉 bm 的内容
而且你不止一次这样做
scaledBitmap[i] = Bitmap.createScaledBitmap(bm, reqW[i], reqH[i], true);
bm.recycle();
bm = null;
}
System.gc();
WeakReference <Bitmap[] > sc = new WeakReference <Bitmap[]> (scaledBitmap);
你应该这样做:
ArrayList<WeakReference<Bitmap>>scaledBitmaps= new ArrayList<WeakReference<Bitmap>>();
scaledBitmaps.add(new WeakReference<Bitmap>(Bitmap.createScaledBitmap...));
and do not use Bitmap[] array
关于android - 尽管使用弱引用内存泄漏，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17272474/