我正在使用列表视图来显示res / drawable文件夹中的一组图像。为此，我创建了一个适配器类，它将填充（main.xml）。我已经编码，如果单击listItem，图像应该在新活动的全屏显示。此外，我需要包括图像缩放功能。你可以帮助你将缩放功能附加到以下代码。
MainActivity.java
public class MainActivity extends ListActivity
{
static final String[] Furniture_types = new String[] { "Type1", "Type2","Type3", "Type4"};
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setListAdapter(new FurnitureArrayAdapter(this,Furniture_types ));
}
protected void onListItemClick(ListView l, View v, int position, long id)
{
Intent myIntent = new Intent();
myIntent.setClassName("com.mink7.furniture.list","com.mink7.furniture.list.ImageDisplayActivity");
myIntent.putExtra("ID", id);
startActivity(myIntent);
}
}
FurnitureArrayAdapter.java
public class FurnitureArrayAdapter extends ArrayAdapter<String>
{
private final Context context;
private final String[] values;
public FurnitureArrayAdapter(Context context, String[] values)
{
super(context, R.layout.activity_main, values);
this.context = context;
this.values = values;
}
public View getView(int position, View convertView, ViewGroup parent)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.activity_main, parent, false);
TextView textView = (TextView) rowView.findViewById(R.id.type);
ImageView imageView = (ImageView) rowView.findViewById(R.id.photo);
textView.setText(values[position]);
String s = values[position];
System.out.println(s);
if (s.equals("Type1")) {
imageView.setImageResource(R.drawable.img1);
} else if (s.equals("Type2")) {
imageView.setImageResource(R.drawable.img2);
} else if (s.equals("Type3")) {
imageView.setImageResource(R.drawable.img3);
} else {
imageView.setImageResource(R.drawable.img4);
}
return rowView;
}
}
ImageDisplayActivity.java
public class ImageDisplayActivity extends Activity
{
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.imagedisp);
Bundle extras = getIntent().getExtras();
long id =extras.getLong("ID");
String s=String.valueOf(id);
ImageView image = (ImageView) findViewById(R.id.imageView1);
System.out.println(s);
if (s.equals("0"))
{
image.setImageResource(R.drawable.img1);
}
else if (s.equals("1"))
{
image.setImageResource(R.drawable.img2);
}
else if (s.equals("2"))
{
image.setImageResource(R.drawable.img3);
}
else
{
image.setImageResource(R.drawable.img4);
}
}
}
答案 0 :(得分：2)
以下代码描述了一个实现某些方法来实现放大和缩小功能的类。您可以在自己的类中修改并包含此代码。
import android.app.Activity;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.util.FloatMath;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class ZoomInZoomOut extends Activity implements OnTouchListener
{
private static final String TAG = "Touch";
@SuppressWarnings("unused")
private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f;
// 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.imageView);
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());
}
}