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缩放/平移带有ImageView的FrameLayout

android
4
我有一个带有背景图片和一些ImageView的FrameLayout。它还有一些嵌套的布局（比如RelativeLayout）。不管怎样，我想实现缩放和平移的功能。我使用了GestureDetection和setScaleX/setScaleY以及translateX/translateY方法，这部分实现了一部分功能，但是translate有时会将整个布局移动到屏幕之外，还有其他小问题。
你建议采用什么方法呢？或者是否有我可以参考的代码？
谢谢。
你看过这个吗 - https://developer.android.com/training/gestures/scale.html。这是谷歌推荐的处理缩放和平移的方法。 - Oleksandr
@Snake，实现这个有什么进展吗？请告诉我，我也有同样的需求要实现。 - Adi
@Adi，我最终使用了一个叫做photozoom（或类似的）的库来跟踪背景图像上的缩放并将其传播到其他部分。 - Snake
2个回答
1

请查看https://github.com/sephiroth74/ImageViewZoom - 它可能会对你有所帮助。

1. 创建一个名为“Touch”的新类

public class Touch implements OnTouchListener {

Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
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;

@Override
public boolean onTouch(View v, MotionEvent event) {
    ImageView view = (ImageView) v;
    dumpEvent(event);
    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:
            oldDist = spacing(event);
            if (oldDist > 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 newDist = spacing(event);
                if (newDist > 10f) {
                    matrix.set(savedMatrix);
                    float scale = newDist / oldDist;
                    matrix.postScale(scale, scale, mid.x, mid.y);
                }
            }
            break;
    }

    view.setImageMatrix(matrix);
    return true; // indicate event was handled
}

// 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("]");
}

// Determine the space between the first two fingers
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);
}

// Calculate the mid point of the first 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);
}}

2. 将您的活动更改如下

 FrameLayout fm =(FrameLayout)findViewById(R.id.fm);
 fm.setOnTouchListener(new Touch());
这是针对单个图像的缩放。我上面的问题是，如果您的布局周围有多个图像。不是针对单个图像进行缩放。 - Snake
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