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这个应用程序运行没有问题，但太慢了。它在一个 UI 线程上运行所有内容，当在 gridView 中加载了许多图像的页面时，页面加载之前需要很长时间。我使用名为“ Processing Bitmaps Off the UI Thread ”的 android 文档中的代码解决了这个问题

使用代码，它现在加载 gridview 页面变化很快，并且在您可以看到它在单独的后台线程中一一加载每个小位图图像之后。

在这个使用 AsyncTask 作为多线程部分的代码中，它还使用了几种方法来减小图像大小以消除内存不足错误。我在该程序的前一个单线程版本中使用的相同图像缩减方法。无论图像多大，都不应大于图像缩小方法设置的 200dp 乘以 200dp。它可以在没有多线程的旧版本的应用程序中运行，并且在新版本的应用程序中大部分看起来都可以。但有一个奇怪的问题。

我现在遇到了与 BitmapFactory 解码方法相关的内存错误。

发生这种情况的原因是我开始使用许多较小的图像测试该应用程序，并在其中放置一个大约 10,000 X 10,000 像素的位图。这不应该引起问题，因为使用位图工厂选项正在减少图像。

错误不会立即发生。该应用程序可以正常工作一段时间，但在活动之间来回移动和来回移动之后。3到5分钟后它会崩溃。

还有其他人有这样的问题吗？你能提供任何可能是我可以检查的原因的想法吗？或者帮助我开始寻找正确的方向？

图像缩小代码如下所示，下面是 logcat 输出。

    class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
    private final WeakReference<ImageView> imageViewReference;
    private String data = "";

    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(String... params) {
        data = params[0];
       // return imageProcessor(data);
        return decodeSampledBitmapFromResource(data, 100, 100);
    }

    // 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);
            }
        }
    }
  }// end BitmapWorkerTask extends AsyncTask class

      public static Bitmap decodeSampledBitmapFromResource(String fileName, int reqWidth, int reqHeight) {

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

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

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;

    return BitmapFactory.decodeFile(fileName, options);


}//end decodeSampledBitmapfromresource method


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) {
    if (width > height) {
        inSampleSize = Math.round((float)height / (float)reqHeight);
    } else {
        inSampleSize = Math.round((float)width / (float)reqWidth);
    }
}
return inSampleSize;
}// end calculateInSampleSize method


日志猫

17:52:28.340: E/AndroidRuntime(7812): FATAL EXCEPTION: main
17:52:28.340: E/AndroidRuntime(7812): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.v.splitter/com.v.splitter.AudioViewer}: android.view.InflateException: Binary XML file line #63: Error inflating class <unknown>
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread.access$600(ActivityThread.java:123)
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
17:52:28.340: E/AndroidRuntime(7812): at android.os.Handler.dispatchMessage(Handler.java:99)
17:52:28.340: E/AndroidRuntime(7812): at android.os.Looper.loop(Looper.java:137)
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread.main(ActivityThread.java:4424)
17:52:28.340: E/AndroidRuntime(7812): at java.lang.reflect.Method.invokeNative(Native Method)
17:52:28.340: E/AndroidRuntime(7812): at java.lang.reflect.Method.invoke(Method.java:511)
17:52:28.340: E/AndroidRuntime(7812): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
17:52:28.340: E/AndroidRuntime(7812): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
17:52:28.340: E/AndroidRuntime(7812): at dalvik.system.NativeStart.main(Native Method)
17:52:28.340: E/AndroidRuntime(7812): Caused by: android.view.InflateException: Binary XML file line #63: Error inflating class <unknown>
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.createView(LayoutInflater.java:606)
17:52:28.340: E/AndroidRuntime(7812): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
17:52:28.340: E/AndroidRuntime(7812): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:255)
17:52:28.340: E/AndroidRuntime(7812): at android.app.Activity.setContentView(Activity.java:1835)
17:52:28.340: E/AndroidRuntime(7812): at com.v.splitter.AudioViewer.onCreate(AudioViewer.java:63)
17:52:28.340: E/AndroidRuntime(7812): at android.app.Activity.performCreate(Activity.java:4465)
17:52:28.340: E/AndroidRuntime(7812): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
17:52:28.340: E/AndroidRuntime(7812): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
17:52:28.340: E/AndroidRuntime(7812): ... 11 more
17:52:28.340: E/AndroidRuntime(7812): Caused by: java.lang.reflect.InvocationTargetException
17:52:28.340: E/AndroidRuntime(7812): at java.lang.reflect.Constructor.constructNative(Native Method)
17:52:28.340: E/AndroidRuntime(7812): at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
17:52:28.340: E/AndroidRuntime(7812): at android.view.LayoutInflater.createView(LayoutInflater.java:586)
17:52:28.340: E/AndroidRuntime(7812): ... 24 more
12-17:52:28.340: E/AndroidRuntime(7812): Caused by: java.lang.OutOfMemoryError
17:52:28.340: E/AndroidRuntime(7812): at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method)
17:52:28.340: E/AndroidRuntime(7812): at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:483)
17:52:28.340: E/AndroidRuntime(7812): at android.graphics.BitmapFactory.decodeResourceStream(BitmapFactory.java:351)
17:52:28.340: E/AndroidRuntime(7812): at android.graphics.drawable.Drawable.createFromResourceStream(Drawable.java:773)
17:52:28.340: E/AndroidRuntime(7812): at android.content.res.Resources.loadDrawable(Resources.java:1937)
17:52:28.340: E/AndroidRuntime(7812): at android.content.res.TypedArray.getDrawable(TypedArray.java:601)
17:52:28.340: E/AndroidRuntime(7812): at android.view.View.<init>(View.java:2785)
17:52:28.340: E/AndroidRuntime(7812): at android.view.View.<init>(View.java:2722)
17:52:28.340: E/AndroidRuntime(7812): at android.view.ViewGroup.<init>(ViewGroup.java:379)
17:52:28.340: E/AndroidRuntime(7812): at android.widget.RelativeLayout.<init>(RelativeLayout.java:174)
17:52:28.340: E/AndroidRuntime(7812): ... 27 more
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1 回答 1

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仍然需要加载 10,000x10,000 的图像以供 BitmapFactory 调整大小。我建议将该图像缩小。

无论如何，如果您使用了大量的位图，请确保在使用完它们后回收它们。它们消耗垃圾收集需要一段时间才能到达的本机资源。

bitmap.recycle();

只要确保在回收后不要使用Bitmap，因为会抛出异常。

于 2012-12-10T11:22:17.070 回答