在我的 android 应用程序中，我有一个裁剪图像。所以，我编写了一个CropBox扩展的ImageView. 我想移动裁剪框并调整其大小。我使用OnTouchListener，但 MotionEvent.ACTION_MOVE 不起作用。我用谷歌搜索，但我什么也没抓到。
属性类：
public class Attr {
public static final float CROP_BOX_START_X = 5;
public static final float CROP_BOX_START_Y = 5;
public static final float CROP_BOX_END_X = 305;
public static final float CROP_BOX_END_Y = 105;
}
裁剪框类：
public class CropBox extends ImageView {
private Paint paint = new Paint();
public CropBox(Context context) {
super(context);
}
public CropBox(Context context, AttributeSet attributeSet) {
super(context, attributeSet);
}
@Override
public void onDraw(Canvas canvas) {
float[][] circleXY = {
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y},
{(Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y},
{(Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_START_X, (Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2},
{Attr.CROP_BOX_END_X, (Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2}
};
float[][] lineXY = {
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_START_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_START_X, Attr.CROP_BOX_END_Y},
{Attr.CROP_BOX_END_X, Attr.CROP_BOX_START_Y, Attr.CROP_BOX_END_X, Attr.CROP_BOX_END_Y}
};
paint.setColor(Color.CYAN);
paint.setStrokeWidth(1);
for(int i = 0 ; i < circleXY.length ; i++)
canvas.drawCircle(circleXY[i][0], circleXY[i][1], 5, paint);
paint.setStrokeWidth(2);
for(int i = 0 ; i < lineXY.length ; i++)
canvas.drawLine(lineXY[i][0], lineXY[i][1], lineXY[i][2], lineXY[i][3], paint);
}
}
CropTestActivity 类：
public class CropTestActivity extends Activity {
private ImageView imageView;
private CropBox cropBorder;
private RelativeLayout relativeLayout;
private RelativeLayout.LayoutParams layoutParams;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.crop_test_layout);
imageView = (ImageView)findViewById(R.id.android_image);
cropBorder = new CropBox(this);
relativeLayout = (RelativeLayout)findViewById(R.id.crop_test_layout);
layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, RelativeLayout.LayoutParams.FILL_PARENT);
ViewTreeObserver viewTreeObserver = imageView.getViewTreeObserver();
if(viewTreeObserver.isAlive()) {
viewTreeObserver.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
public void onGlobalLayout() {
layoutParams.leftMargin = imageView.getWidth() / 2 - (int)((Attr.CROP_BOX_START_X + Attr.CROP_BOX_END_X) / 2) + imageView.getLeft();
layoutParams.topMargin = imageView.getHeight() / 2 - (int)((Attr.CROP_BOX_START_Y + Attr.CROP_BOX_END_Y) / 2) + imageView.getTop();
}
});
}
relativeLayout.addView(cropBorder, layoutParams);
cropBorder.setOnTouchListener(new Crop());
}
}
作物类别：
public class Crop implements OnTouchListener {
private static final int NONE = 0;
private static final int BOX_DRAG = 1;
private static final int BORDER_DRAG = 2;
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
private PointF start = new PointF();
private int mode = NONE;
private float cropBoxStartX = Attr.CROP_BOX_START_X;
private float cropBoxStartY = Attr.CROP_BOX_START_Y;
private float cropBoxEndX = Attr.CROP_BOX_END_X;
private float cropBoxEndY = Attr.CROP_BOX_END_Y;
public boolean onTouch(View view, MotionEvent event) {
CropBox cropBox = (CropBox)view;
switch(event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
if(event.getX() > cropBoxStartX && event.getX() < cropBoxEndX && event.getY() > cropBoxStartY && event.getY() < cropBoxEndY)
mode = BOX_DRAG;
else if(event.getX() == cropBoxStartX || event.getX() == cropBoxEndX || event.getY() == cropBoxStartY || event.getY() == cropBoxEndY)
mode = BORDER_DRAG;
else
mode = NONE;
break;
case MotionEvent.ACTION_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if(mode == BOX_DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);
}
else if(mode == BORDER_DRAG) {
}
break;
}
cropBox.setImageMatrix(matrix);
return true;
}
}
布局 XML：
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/crop_test_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<ImageView
android:id="@+id/android_image"
android:src="@drawable/android"
android:layout_width="300dp"
android:layout_height="300dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:layout_marginBottom="10dp"
android:layout_marginLeft="10dp"
android:layout_gravity="center"
android:scaleType="fitXY"
android:contentDescription="@string/android_image_description" >
</ImageView>
</RelativeLayout>
谢谢你的帮助。