レイアウトにImageViewがあり、ImageViewでOnTouchListenerを設定してImageViewをドラッグします。完全に機能しています。私の問題は、ImageViewがレイアウト範囲外に移動するのを防ぐにはどうすればよいですか？
これは私のコードです：
アクティビティクラス：
public class RepositionTestActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.reposition_test_layout);
ImageView imageView = (ImageView)findViewById(R.id.android);
imageView.setOnTouchListener(new Touch());
}
}
タッチクラス：
public class Touch implements OnTouchListener {
private static final int NONE = 0;
private static final int DRAG = 1;
private static final int ZOOM = 2;
private static final float MIN_ZOOM = 1f;
private static final float MAX_ZOOM = 5f;
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
private PointF start = new PointF();
private PointF mid = new PointF();
private int mode = NONE;
private float oldDistance = 1f;
public boolean onTouch(View view, MotionEvent event) {
ImageView imageView = (ImageView)view;
switch(event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDistance = spacing(event);
if(oldDistance > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
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 newDistance = spacing(event);
if(newDistance > 10f) {
matrix.set(savedMatrix);
float scale = newDistance / oldDistance;
float[] values = new float[9];
matrix.getValues(values);
float currentScale = values[Matrix.MSCALE_X];
if(scale * currentScale > MAX_ZOOM)
scale = MAX_ZOOM / currentScale;
else if (scale * currentScale < MIN_ZOOM)
scale = MIN_ZOOM / currentScale;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
imageView.setImageMatrix(matrix);
return true;
}
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) {
point.set((event.getX(0) + event.getX(1)) / 2, (event.getY(0) + event.getY(1)) / 2);
}
}
レイアウトxml：
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/reposition_test_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<ImageView
android:id="@+id/android"
android:src="@drawable/android"
android:layout_width="300dp"
android:layout_height="300dp"
android:scaleType="matrix"
android:contentDescription="@string/android_description" >
</ImageView>
</LinearLayout>
