在图像上绘制一个矩形
问题描述:
在我的应用程序中,有一项活动从资源中获取图像,我已将平移和缩放功能合并在一起。在图像上绘制一个矩形
我现在想要的是在矩形上绘制矩形,矩形也应该放大并平移图像。我试图扩大观点并重写平局。只有矩形来了,而不是图像。如果有人能帮助我,那将会非常有帮助。
public class XYZ extends Activity implements OnTouchListener {
private static final String TAG = "Touch" ;
// These matrices will be used to move and zoom image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
private Bitmap mBitmap;
ImageView mapView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.jubileemap);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inDither= false;
options.inInputShareable=true;
options.inTempStorage=new byte[8*1024];
mapView = (ImageView) findViewById(R.id.abc);
mBitmap =BitmapFactory.decodeResource(XYZ.this.getResources(),R.drawable.pqr, options);
mapView.setImageBitmap(mBitmap);
mapView.setOnTouchListener(JubileeMaps.this);
}
@Override
public void onLowMemory(){
Log.e("low memory", "low");
System.gc();
}
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);
}
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);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
mapView.setScaleType(ImageView.ScaleType.MATRIX);
// TODO Auto-generated method stub
ImageView view = (ImageView) v;
// Dump touch event to log
dumpEvent(event);
// Handle touch events here...
/*spacing(event);
midPoint(point,event);*/
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x,
event.getY() - start.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist/oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
}
// Perform the transformation
view.setImageMatrix(matrix);
return true; // indicate event was handled
}
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(TAG, sb.toString());
}
@Override
public void onPause()
{
super.onPause();
System.gc();
}
@Override
protected void onResume()
{
super.onResume();
System.gc();
}
@Override
protected void onDestroy() {
super.onDestroy();
System.gc();
mapView.setImageBitmap(null);
mBitmap.recycle();
}
}
而我使用的XML是:
<ImageZoomView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/zoomview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
这是我正在using..now上我想画一个recagle标记的面积将图像的顶部代码放大和缩小,因为我的形象does.But一直无法实现这一点。
答
您应该重写onDraw方法。
一定要保持对super.onDraw()的调用,并在该行下执行自定义绘图。
+0
我已经尝试过,但会发生什么情况是当我只使用画布绘制我没有得到矩形,当我重写onDraw方法只有矩形来。我已经把我的代码和XML。如果你可以请检查一下,并建议我一些东西,如果可能的话,给我链接演示。谢谢。 – amithotu
你可以张贴重载绘制方法的代码? – slayton
我只是使用画布绘制矩形在它上面......这是一种方式,而我尝试的另一件事是创建一个私人类,并扩展视图并重写onDraw方法,两种方法我没有得到我想要什么,要么我得到地图或矩形。请帮助我。 – amithotu