我在我的应用程序中在ImageView中显示位图图像时遇到了很大的问题。我有一个活动，显示2列4行的8张照片。当我点击这8张照片中的任何照片时，照片应该与设备尺寸一样大。但在这里我有一个问题是，当我点击任何照片时，它会给我一些OutOfMemoryError错误。请参考我的下面的代码，我在imageView中显示这张大照片：
public class ViewFullImage extends Activity {
private Bitmap bitmap_general;
private ImageView iv;
private static final String path = "mfc/cam_img/";
private int s_id;
private int intentKey;
private int width;
private int height;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.view_draw_picture);
// Display display= ((WindowManager) getSystemService(ViewFullImage.WINDOW_SERVICE)).getDefaultDisplay();
// width = display.getWidth();
// height = display.getHeight();
Display mDisplay= ((Activity) this).getWindowManager().getDefaultDisplay();
width= mDisplay.getWidth();
height= mDisplay.getHeight();
Log.v("","===================== viewFullImage.java================");
Log.v("","This is height ViewImage : "+height/2);
Log.v("","This is width ViewImage : "+width/2);
s_id=getIntent().getIntExtra("s_id", -1);
intentKey=getIntent().getIntExtra("iv", -1);
iv = (ImageView)findViewById(R.id.image);
new LongOperation().execute();
}
//Image Rotation
Bitmap rotateBitmap(Bitmap bitmap)
{
Matrix matrix = new Matrix();
matrix.postRotate(90);
Bitmap bitmap1 = Bitmap.createBitmap(bitmap, 0, 0,
bitmap.getWidth(), bitmap.getHeight(),
matrix, true);
bitmap.recycle();
bitmap=null;
return bitmap1;
}
//Calculate Image size
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;
}
public void onDestroy() {
super.onDestroy();
System.gc();
}
public static Bitmap decodeSampleImage(File f, int width, int height) {
try {
System.gc(); // First of all free some memory
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
// The new size we want to scale to
final int requiredWidth = width;
final int requiredHeight = height;
// Find the scale value (as a power of 2)
int sampleScaleSize = 1;
while (o.outWidth / sampleScaleSize / 2 >= requiredWidth && o.outHeight / sampleScaleSize / 2 >= requiredHeight)
sampleScaleSize *= 2;
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = sampleScaleSize;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (Exception e) {
Log.v("", e.getMessage()); // We don't want the application to just throw an exception
}
return null;
}
int h;
int w;
class LongOperation extends AsyncTask<String, Void, String> {
private ProgressDialog Dialog = new ProgressDialog(ViewFullImage.this);
@Override
protected String doInBackground(String... aurl) {
runOnUiThread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
File Dir= Environment.getExternalStorageDirectory();
File imageDirectory = new File(Dir,path);
File file = new File(imageDirectory, "img_"+s_id+"_"+intentKey+".jpg");
String ImgFile_Name = file.getAbsolutePath();
BitmapFactory.Options options = new BitmapFactory.Options();
BitmapFactory.decodeFile(file.getAbsolutePath(),options);
h = options.outHeight;
w = options.outWidth;
options.inSampleSize = calculateInSampleSize(options, width/5, height/5);
options.inJustDecodeBounds = false;
options.inScaled=true;
if(bitmap_general!=null){
bitmap_general.recycle();
bitmap_general=null;
}
bitmap_general = BitmapFactory.decodeFile(ImgFile_Name,options);
try {
if(h<w)
{
iv.setImageBitmap(rotateBitmap(bitmap_general));
}
else{
iv.setImageBitmap(bitmap_general);
}
} catch (Exception e) {
e.printStackTrace();
if(bitmap_general!=null){
bitmap_general.recycle();
bitmap_general=null;
}
System.gc();
}
finally{
if(bitmap_general!=null){
bitmap_general.recycle();
bitmap_general=null;
}
System.gc();
}
}
});
return null;
}
protected void onPreExecute() {
Dialog.setMessage("Loading Image...");
Dialog.show();
}
protected void onPostExecute(String resultGot) {
Dialog.dismiss();
}
}
}
Xml布局文件：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000000"
android:id="@+id/RootView">
<ImageView
android:id="@+id/image"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:adjustViewBounds="true"/>
</RelativeLayout>
在上面的代码中，我有点混淆应该在下面的语句中输入的高度和宽度值：
options.inSampleSize = calculateInSampleSize(options, width, height);
请有人告诉我我的代码在哪里做坏事吗？
答案 0 :(得分：0)
似乎你根本没有使用decodeSampleImage，而是你正在调用BitmapFactory.decodeFile（file.getAbsolutePath（），options）;因此，您无法正确处理大图像。 Here您可以找到有关如何有效加载大图像的有用信息。您可以将它作为起点。