在SD卡的列表视图中显示图像时出现内存不足错误
我知道它是因为我需要对位图进行二次采样,因为它们是大型的8mp图像,如果我将它们缩小到600 x 450则会完全加载
我使用以下
正常加载它们 Bitmap bmp = BitmapFactory.decodeFile("/storage/emulated/0/Pictures/" + text7[i]);
item_details.setImage(bmp);
正如我所说,如果我使用全尺寸图像,这会导致应用程序崩溃
我有以下两种方法,它们对位图进行了子样本
public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
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) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
问题是我不知道如何调用它以便显示
这是我填写listview的方法
private ArrayList<ListItemDetails> GetSearchResults() {
// TODO Auto-generated method stub
ArrayList<ListItemDetails> results = new ArrayList<ListItemDetails>();
ImageView imageview = (ImageView) findViewById(R.id.imageView1);
DBAdapter db = new DBAdapter(this);
db.open();
Cursor c = db.getAsset3();
String[] text1 = new String[c.getCount()];
String[] text2 = new String[c.getCount()];
String[] text3 = new String[c.getCount()];
String[] text4 = new String[c.getCount()];
String[] text5 = new String[c.getCount()];
String[] text6 = new String[c.getCount()];
String[] text7 = new String[c.getCount()];
for(int i = 0; c.moveToNext(); ++i)
{
text1[i] = c.getString(0);
text2[i] = c.getString(1);
text3[i] = c.getString(2);
text4[i] = c.getString(3);
text5[i] = c.getString(4);
text6[i] = c.getString(5);
text7[i] = c.getString(6);
}
c.close();
for(int i=0;i<text1.length;i++)
{
item_details= new ListItemDetails();
item_details.setSR1("School: " + text1[i]);
item_details.setSR2("Building: " + text2[i]);
item_details.setSR3("Floor: " + text3[i]);
item_details.setSR4("Room: " + text4[i]);
item_details.setSR5("Drawing Ref: " + text5[i]);
item_details.setSR6("Fault: " + text6[i]);
item_details.setSR7("Picture Filename: " + text7[i]);
String picFormat="Harris%d.jpg";
String pic = String.format(picFormat, i+1);
/////////////////////////////////////////////////////////////////
/// Load bitmap
imageview.setImageBitmap(decodeSampledBitmapFromResource(getResources(),
R.id.imageView1, 100, 100));
results.add(item_details);
}
return results;
}
它似乎工作,因为列表视图加载,每个项目上的所有文本都在那里,但图像是空白
任何我出错的想法?
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答案 0 :(得分:1)
您没有将图像文件名传递给decodeSampledBitmapFromResource
,那么如何知道要加载哪个文件?您传入的资源ID是ImageView的资源ID,而不是图像资源的资源ID。
如果要从给定文件名而非资源的文件加载图像,则需要使用BitmapFactory.decodeFile()而不是BitmapFactory.decodeResource更改decodeSampledBitmapFromResource
从文件加载,例如这样:
public static Bitmap decodeSampledBitmapFromFile(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);
}
然后更改您的ArrayList代码以将文件名传递给它:
item_details.setImageBitmap(decodeSampledBitmapFromFile("/storage/emulated/0/Pictures/" + text7[i], 100, 100));
答案 1 :(得分:-1)
你可以使用Picasso http://square.github.io/picasso/,这很简单,你可以避免很多麻烦。