在UIScrollView的
android中有一个等价物,我可以在其中滑动图像.谢谢.
对不起,我没有更具体.我需要向四面八方滑行. Androids ScrollView不会这样做.我一直在使用一个有效的WebView,但它只适用于4.0或更高版本.
这就是我提出的.我将我的ImageView放在WebView中,并在ImageView上分配了setOnTouchListener.它似乎运作良好.
web = new WebView(this);
web.setVerticalScrollBarEnabled(false);
web.setHorizontalScrollBarEnabled(false);
web.setBackgroundColor(Color.RED);
web.setId(100);
RelativeLayout.LayoutParams layoutForContainer = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutForContainer.height = 300;
layoutForContainer.width = 300;
layoutForContainer.addRule(RelativeLayout.CENTER_IN_PARENT);
web.setLayoutParams(layoutForContainer);
layout.addView(web);
myImageView = new ImageView(this);
myImageView.setImageResource(R.drawable.myImage);
RelativeLayout.LayoutParams layoutForLargeImage = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutForLargeImage.height = (int) 768;
layoutForLargeImage.width = (int) 1024;
myImageView.setLayoutParams(layoutForLargeImage);
web.addView(myImageView);
myImageView.setOnTouchListener(new View.OnTouchListener() {
float downX, downY;
int scrollByX, scrollByY;
public boolean onTouch(View view, MotionEvent event) {
float currentX, currentY;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
downX = event.getX();
downY = event.getY();
break;
case MotionEvent.ACTION_MOVE:
currentX = event.getX();
currentY = event.getY();
scrollByX = (int)(downX - currentX);
scrollByY = (int)(downY - currentY);
myImageView.scrollBy(scrollByX, scrollByY);
downX = currentX;
downY = currentY;
break;
}
return true;
}
});
最佳答案 这个问题已经差不多一年了,但它是谷歌搜索这个问题的首选,所以我想我会添加一些细节.
如果您正在寻找可以滚动的通用单向视图,那么使用Android内置ScrollView的其他答案将正常工作.
但是,如果您想要iOS UIScrollView的多方面方面,则必须设计/使用自定义视图(或使用hack,例如使用webview).可以在此处的相关问题中找到可以执行此操作的视图的示例实现：
View with horizontal and vertical pan/drag and pinch-zoom
然后根据您的喜好,您可以根据需要进行修改,例如没有缩放的此实现(只是平移)：
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.view.*;
public class MultiDirectionPanGroup extends ViewGroup {
private static final int INVALID_POINTER_ID = 1;
private int mActivePointerId = INVALID_POINTER_ID;
private float mPosX;
private float mPosY;
private Matrix mTranslateMatrix = new Matrix();
private Matrix mTranslateMatrixInverse = new Matrix();
private float mLastTouchX;
private float mLastTouchY;
private float mFocusY;
private float mFocusX;
private float[] mInvalidateWorkingArray = new float[6];
private float[] mDispatchTouchEventWorkingArray = new float[2];
private float[] mOnTouchEventWorkingArray = new float[2];
public MultiDirectionPanGroup(Context context) {
super(context);
mTranslateMatrix.setTranslate(0, 0);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
if (child.getVisibility() != GONE) {
child.layout(l, t, l+child.getMeasuredWidth(), t + child.getMeasuredHeight());
}
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
if (child.getVisibility() != GONE) {
measureChild(child, widthMeasureSpec, heightMeasureSpec);
}
}
}
@Override
protected void dispatchDraw(Canvas canvas) {
canvas.save();
canvas.translate(mPosX, mPosY);
super.dispatchDraw(canvas);
canvas.restore();
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
mDispatchTouchEventWorkingArray[0] = ev.getX();
mDispatchTouchEventWorkingArray[1] = ev.getY();
mDispatchTouchEventWorkingArray = screenPointsToScaledPoints(mDispatchTouchEventWorkingArray);
ev.setLocation(mDispatchTouchEventWorkingArray[0],
mDispatchTouchEventWorkingArray[1]);
return super.dispatchTouchEvent(ev);
}
/**
* Although the docs say that you shouldn't override this, I decided to do
* so because it offers me an easy way to change the invalidated area to my
* likening.
*/
@Override
public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
mInvalidateWorkingArray[0] = dirty.left;
mInvalidateWorkingArray[1] = dirty.top;
mInvalidateWorkingArray[2] = dirty.right;
mInvalidateWorkingArray[3] = dirty.bottom;
mInvalidateWorkingArray = scaledPointsToScreenPoints(mInvalidateWorkingArray);
dirty.set(Math.round(mInvalidateWorkingArray[0]), Math.round(mInvalidateWorkingArray[1]),
Math.round(mInvalidateWorkingArray[2]), Math.round(mInvalidateWorkingArray[3]));
location[0] *= mScaleFactor;
location[1] *= mScaleFactor;
return super.invalidateChildInParent(location, dirty);
}
private float[] scaledPointsToScreenPoints(float[] a) {
mTranslateMatrix.mapPoints(a);
return a;
}
private float[] screenPointsToScaledPoints(float[] a){
mTranslateMatrixInverse.mapPoints(a);
return a;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
mOnTouchEventWorkingArray[0] = ev.getX();
mOnTouchEventWorkingArray[1] = ev.getY();
mOnTouchEventWorkingArray = scaledPointsToScreenPoints(mOnTouchEventWorkingArray);
ev.setLocation(mOnTouchEventWorkingArray[0], mOnTouchEventWorkingArray[1]);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
// Save the ID of this pointer
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE: {
// Find the index of the active pointer and fetch its position
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
mTranslateMatrix.preTranslate(dx, dy);
mTranslateMatrix.invert(mTranslateMatrixInverse);
mLastTouchX = x;
mLastTouchY = y;
invalidate();
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
// Extract the index of the pointer that left the touch sensor
final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
return true;
}
}
