我正在尝试在 Android 内置应用程序的图库中显示下载的图像。但我面临着从 sdcard 存储和删除图像的问题。但我可以使用 MediaPlayer 播放歌曲而无需存储歌曲。
像 MediaPlayer 类一样，是否有任何直接类来渲染 url 图像以获得放大和缩小的直接功能？
问问题
281 次
2 回答
0
什么都没有建。您将需要一个图像加载实现和一个捏缩放实现。
以下两个是我个人可以推荐的。
https://github.com/nostra13/Android-Universal-Image-Loader
和
https://github.com/chrisbanes/PhotoView
public class ImageViewerActivity extends Activity {
public static final String EXTRA_URL = ImageViewerActivity.class.getName() + ".EXTRA_URL";
private ImageView mImageView;
private PhotoViewAttacher mAttacher;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.image_viewer_activity);
mImageView = (ImageView) findViewById(R.id.iv_photo);
//retrieve image url from extras
String url = getIntent().getStringExtra(EXTRA_URL);
//The MAGIC happens here!
mAttacher = new PhotoViewAttacher(mImageView);
ImageLoader.getInstance().loadImage(url, new ImageLoadingListener() {
@Override
public void onLoadingStarted(String imageUri, View view) {
//To change body of implemented methods use File | Settings | File Templates.
}
@Override
public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
//To change body of implemented methods use File | Settings | File Templates.
}
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
mImageView.setImageBitmap(loadedImage);
mAttacher.update();
}
@Override
public void onLoadingCancelled(String imageUri, View view) {
//To change body of implemented methods use File | Settings | File Templates.
}
});
}
@Override
public void onDestroy() {
super.onDestroy();
// Need to call clean-up
mAttacher.cleanup();
}
}
和布局...
<merge xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView android:id="@+id/iv_photo"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</merge>
于 2013-05-06T10:32:59.677 回答
0
请参阅下面的代码以显示具有缩放功能的图像。
public class AndroidZoomActivity extends Activity implements OnTouchListener {
private static final String TAG = "Touch";
// These matrices will be used to scale points of the image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// The 3 states (events) which the user is trying to perform
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// these PointF objects are used to record the point(s) the user is touching
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView view = (ImageView) findViewById(R.id.im_card);
view.setImageBitmap((getBitmap("Here ImageURL")));
view.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: // first finger down only
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG"); // write to LogCat
mode = DRAG;
break;
case MotionEvent.ACTION_UP: // first finger lifted
case MotionEvent.ACTION_POINTER_UP: // second finger lifted
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 5f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY()
- start.y); // create the transformation in the matrix
// of points
} else if (mode == ZOOM) {
// pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 5f) {
matrix.set(savedMatrix);
scale = newDist / oldDist; // setting the scaling of the
// matrix...if scale > 1 means
// zoom in...if scale < 1 means
// zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix); // display the transformation on screen
return true; // indicate event was handled
}
/*
*
--------------------------------------------------------------------------
* Method: spacing Parameters: MotionEvent Returns: float Description:
* checks the spacing between the two fingers on touch
* ----------------------------------------------------
*/
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
/*
*
--------------------------------------------------------------------------
* Method: midPoint Parameters: PointF object, MotionEvent Returns: void
* Description: calculates the midpoint between the two fingers
* ------------------------------------------------------------
*/
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
/** Show an event in the LogCat view, for debugging */
private void dumpEvent(MotionEvent event) {
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN
|| actionCode == MotionEvent.ACTION_POINTER_UP) {
sb.append("(pid ").append(
action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++) {
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
Log.d("Touch Events ---------", sb.toString());
}
/**
* Finctionality for concerting imageURl string into bitmap
* @param url
* @return
*/
public static Bitmap getBitmap(String url) {
Bitmap bm = null;
try {
URL aURL = new URL(url);
URLConnection conn = aURL.openConnection();
conn.connect();
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
bm = BitmapFactory.decodeStream(new FlushedInputStream(is));
bis.close();
is.close();
} catch (Exception e) {
e.printStackTrace();
}
return bm;
}
static class FlushedInputStream extends FilterInputStream {
public FlushedInputStream(InputStream inputStream) {
super(inputStream);
}
@Override
public long skip(long n) throws IOException {
long totalBytesSkipped = 0L;
while (totalBytesSkipped < n) {
long bytesSkipped = in.skip(n - totalBytesSkipped);
if (bytesSkipped == 0L) {
int b = read();
if (b < 0) {
break; // we reached EOF
} else {
bytesSkipped = 1; // we read one byte
}
}
totalBytesSkipped += bytesSkipped;
}
return totalBytesSkipped;
}
}
}
我希望你现在得到了预期的缩放功能代码。
于 2013-05-06T10:27:32.100 回答