Android 如何从库中动态卸载图像?
我有自定义图像视图:Android 如何从库中动态卸载图像?,android,Android,我有自定义图像视图: public class ShadowedImageView extends ImageView { private Paint mPaint; public Bitmap bitmap = null; private Bitmap tempBitmap; private Bitmap thumb; private Bitmap image; public float shadowRadius = 2f; public float shadowDx = 1f; publi
public class ShadowedImageView extends ImageView {
private Paint mPaint;
public Bitmap bitmap = null;
private Bitmap tempBitmap;
private Bitmap thumb;
private Bitmap image;
public float shadowRadius = 2f;
public float shadowDx = 1f;
public float shadowDy = 1f;
public int shadowColor = Color.BLACK;
public int scale = 1;
public int requiredWidth = 768;
public int requiredHeight = 1024;
public int loaded = 0;
public ShadowedImageView(Context context) {
super(context);
setShadow();
loaded = 0;
}
public ShadowedImageView(Context context, AttributeSet attrs){
super(context, attrs);
setShadow();
loaded = 0;
}
public void setShadow(){
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setShadowLayer(shadowRadius, shadowDx, shadowDy, shadowColor);
Resources res = getResources();
Drawable drawable = res.getDrawable(R.drawable.pl);
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pl);
setImageDrawable(drawable);
}
public void refreshShadow(){
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setShadowLayer(shadowRadius, shadowDx, shadowDy, shadowColor);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
}
@Override
protected void onMeasure(int w, int h) {
super.onMeasure(w,h);
int mH, mW;
mW = getSuggestedMinimumWidth() < getMeasuredWidth()? getMeasuredWidth() : getSuggestedMinimumWidth();
mH = getSuggestedMinimumHeight() < getMeasuredHeight()? getMeasuredHeight() : getSuggestedMinimumHeight();
setMeasuredDimension(mW + 5, mH + 5);
}
public void downloadThumb(final Publication pub){
OnClickListener theCommonListener = new OnClickListener(){
@Override
public void onClick(View v) {
Intent intent = new Intent(v.getContext(), PublicationReader.class);
intent.putExtra("pubUrl", pub.publicationUrl);
intent.putExtra("pubPages", pub.publicationPages);
intent.putExtra("pubId", pub.id);
v.getContext().startActivity(intent);
}
};
this.setOnClickListener(theCommonListener);
download(pub.thumbImageUrl);
}
public void download(String fileUrl){
downloadTask t = new downloadTask();
t.loadData(fileUrl, this);
t.execute();
}
private class downloadTask extends AsyncTask<String, Void, Long> {
String fileUrl;
ShadowedImageView imView;
public void loadData(String u, ShadowedImageView i) {
fileUrl = u;
imView = i;
}
@Override
protected Long doInBackground(String... params) {
try{
Bitmap bmImg = null;
URL myFileUrl = null;
try {
if(fileUrl!=null){
myFileUrl= new URL(fileUrl);
}
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
if(myFileUrl!=null){
HttpURLConnection conn=(HttpURLConnection)myFileUrl.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
decodeStream(is);
}
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Long result){
setImageBitmap(bitmap);
invalidate();
}
}
private void decodeStream(InputStream is){
try {
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize=scale;
bitmap = BitmapFactory.decodeStream(is, null, o2);
refreshShadow();
loaded = 1;
invalidate();
} catch (Exception e) {
e.printStackTrace();
}
}
}
图像很大,当应用程序读取很多图像时,我的内存就会耗尽。我想从内存中删除所有不可见的图像,例如:
+-------------+
| screen |
[1] [2] [3] [4] | [5] [6] [7] | [8] [9] [10]
| |
+-------------+
图像1-3和9-10是不必要的-所以我想释放内存。如何操作?我也遇到了同样的问题,您需要做的是创建一个用于gallery的自定义适配器,并使用getView函数循环使用位图:
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(this.myContext);
Bitmap tempBitmap = null;
//Check if my PhotoList at this position is not null...
//Free previous photos
if ((position-3)>=0 && listBitmap.size()-3 >=0 && listBitmap(position-3) != null){
//Here is to free for 1 photo, you can free more ... (3 in your case)
listBitmap(position-3).recycle();
listBitmap(position-3).setBitmap(null);
Log.w(TAG, "Delete Photo-3");
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(this.myContext);
Bitmap tempBitmap = null;
//Check if my PhotoList at this position is not null...
//Free previous photos
if ((position-3)>=0 && listBitmap.size()-3 >=0 && listBitmap(position-3) != null){
//Here is to free for 1 photo, you can free more ... (3 in your case)
listBitmap(position-3).recycle();
listBitmap(position-3).setBitmap(null);
Log.w(TAG, "Delete Photo-3");
}