我有一个ListView,每行上有两个图像按钮。当用户单击列表行时,它将启动一个新活动。我不得不建立我自己的标签,因为相机布局的问题。为结果启动的活动是一个映射。如果我点击我的按钮来启动图像预览(从SD卡加载图像),应用程序从活动返回到ListView活动到结果处理程序,重新启动我的新活动,这只不过是一个图像小部件。

ListView上的图像预览是用光标和ListAdapter完成的。这使得它非常简单,但我不确定我如何可以把一个调整大小的图像(即较小的位大小而不是像素作为图像按钮的src)。我只是调整了从手机摄像头拍下来的图片的大小。

问题是,当它试图返回并重新启动第二个活动时,我得到一个OutOfMemoryError。

是否有一种方法,我可以轻松地构建列表适配器行,在那里我可以调整大小的飞行(位)?

这将是可取的,因为我还需要对每行中的小部件/元素的属性做出一些更改,因为我无法选择一行与触摸屏,因为焦点问题。(我会用滚轮。)

我知道我可以做带外调整并保存我的图像,但这不是我真正想做的,但一些示例代码会很好。

当我在ListView上禁用图像时,它又可以正常工作了。

供你参考:我是这样做的:

String[] from = new String[] { DBHelper.KEY_BUSINESSNAME, DBHelper.KEY_ADDRESS,
    DBHelper.KEY_CITY, DBHelper.KEY_GPSLONG, DBHelper.KEY_GPSLAT,
    DBHelper.KEY_IMAGEFILENAME  + ""};
int[] to = new int[] { R.id.businessname, R.id.address, R.id.city, R.id.gpslong,
    R.id.gpslat, R.id.imagefilename };
notes = new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
setListAdapter(notes);

其中R.id.imagefilename是一个ButtonImage。

这是我的LogCat:

01-25 05:05:49.877: ERROR/dalvikvm-heap(3896): 6291456-byte external allocation too large for this process.
01-25 05:05:49.877: ERROR/(3896): VM wont let us allocate 6291456 bytes
01-25 05:05:49.877: ERROR/AndroidRuntime(3896): Uncaught handler: thread main exiting due to uncaught exception
01-25 05:05:49.917: ERROR/AndroidRuntime(3896): java.lang.OutOfMemoryError: bitmap size exceeds VM budget
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:304)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:149)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:174)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.graphics.drawable.Drawable.createFromPath(Drawable.java:729)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.ImageView.resolveUri(ImageView.java:484)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.ImageView.setImageURI(ImageView.java:281)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.SimpleCursorAdapter.setViewImage(SimpleCursorAdapter.java:183)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.SimpleCursorAdapter.bindView(SimpleCursorAdapter.java:129)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.CursorAdapter.getView(CursorAdapter.java:150)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.AbsListView.obtainView(AbsListView.java:1057)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.ListView.makeAndAddView(ListView.java:1616)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.ListView.fillSpecific(ListView.java:1177)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.ListView.layoutChildren(ListView.java:1454)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.AbsListView.onLayout(AbsListView.java:937)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.View.layout(View.java:5611)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1108)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.onLayout(LinearLayout.java:922)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.View.layout(View.java:5611)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.FrameLayout.onLayout(FrameLayout.java:294)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.View.layout(View.java:5611)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:999)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.LinearLayout.onLayout(LinearLayout.java:920)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.View.layout(View.java:5611)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.widget.FrameLayout.onLayout(FrameLayout.java:294)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.View.layout(View.java:5611)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.ViewRoot.performTraversals(ViewRoot.java:771)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1103)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.os.Handler.dispatchMessage(Handler.java:88)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.os.Looper.loop(Looper.java:123)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at android.app.ActivityThread.main(ActivityThread.java:3742)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at java.lang.reflect.Method.invoke(Method.java:515)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:497)
01-25 05:05:49.917: ERROR/AndroidRuntime(3896):     at dalvik.system.NativeStart.main(Native Method)
01-25 05:10:01.127: ERROR/AndroidRuntime(3943): ERROR: thread attach failed 

我也有一个新的错误时显示的图像:

22:13:18.594: DEBUG/skia(4204): xxxxxxxxxxx jpeg error 20 Improper call to JPEG library in state %d
22:13:18.604: INFO/System.out(4204): resolveUri failed on bad bitmap uri: 
22:13:18.694: ERROR/dalvikvm-heap(4204): 6291456-byte external allocation too large for this process.
22:13:18.694: ERROR/(4204): VM won't let us allocate 6291456 bytes
22:13:18.694: DEBUG/skia(4204): xxxxxxxxxxxxxxxxxxxx allocPixelRef failed

当前回答

在将位图设置为imageview后,像这样回收它:

bitmap.recycle();
bitmap=null;

其他回答

使用这个bitmap.recycle();这有助于没有任何图像质量问题。

在将位图设置为imageview后,像这样回收它:

bitmap.recycle();
bitmap=null;

我对费多的代码做了一些小改进。它基本上做了同样的事情,但没有(在我看来)丑陋的while循环,它总是导致2的幂。向Fedor的原始解决方案致敬,我被卡住了,直到我找到了他的,然后我就能做出这个了:)

 private Bitmap decodeFile(File f){
    Bitmap b = null;

        //Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;

    FileInputStream fis = new FileInputStream(f);
    BitmapFactory.decodeStream(fis, null, o);
    fis.close();

    int scale = 1;
    if (o.outHeight > IMAGE_MAX_SIZE || o.outWidth > IMAGE_MAX_SIZE) {
        scale = (int)Math.pow(2, (int) Math.ceil(Math.log(IMAGE_MAX_SIZE / 
           (double) Math.max(o.outHeight, o.outWidth)) / Math.log(0.5)));
    }

    //Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    fis = new FileInputStream(f);
    b = BitmapFactory.decodeStream(fis, null, o2);
    fis.close();

    return b;
}

这段代码将有助于从可绘制的图中加载大的位图

public class BitmapUtilsTask extends AsyncTask<Object, Void, Bitmap> {

    Context context;

    public BitmapUtilsTask(Context context) {
        this.context = context;
    }

    /**
     * Loads a bitmap from the specified url.
     * 
     * @param url The location of the bitmap asset
     * @return The bitmap, or null if it could not be loaded
     * @throws IOException
     * @throws MalformedURLException
     */
    public Bitmap getBitmap() throws MalformedURLException, IOException {       

        // Get the source image's dimensions
        int desiredWidth = 1000;
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;

        BitmapFactory.decodeResource(context.getResources(), R.drawable.green_background , options);

        int srcWidth = options.outWidth;
        int srcHeight = options.outHeight;

        // Only scale if the source is big enough. This code is just trying
        // to fit a image into a certain width.
        if (desiredWidth > srcWidth)
            desiredWidth = srcWidth;

        // Calculate the correct inSampleSize/scale value. This helps reduce
        // memory use. It should be a power of 2
        int inSampleSize = 1;
        while (srcWidth / 2 > desiredWidth) {
            srcWidth /= 2;
            srcHeight /= 2;
            inSampleSize *= 2;
        }
        // Decode with inSampleSize
        options.inJustDecodeBounds = false;
        options.inDither = false;
        options.inSampleSize = inSampleSize;
        options.inScaled = false;
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        options.inPurgeable = true;
        Bitmap sampledSrcBitmap;

        sampledSrcBitmap =  BitmapFactory.decodeResource(context.getResources(), R.drawable.green_background , options);

        return sampledSrcBitmap;
    }

    /**
     * The system calls this to perform work in a worker thread and delivers
     * it the parameters given to AsyncTask.execute()
     */
    @Override
    protected Bitmap doInBackground(Object... item) {
        try { 
          return getBitmap();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

此问题只发生在Android模拟器中。我在模拟器中也遇到过这个问题,但当我签入设备时,它工作得很好。

所以请签入设备。它可以在设备中运行。