android捏缩放

Question

我的布局包含按钮,textviews等.是否可以在我的布局中实现捏缩放？

Answer 1

查看以下可能对您有所帮助的链接

以下链接提供了最佳示例,您可以重构以满足您的要求.

1. 实施最捏变焦gestur

2. Android的捏

3. GestureDetector.SimpleOnGestureListener

Answer 2

对于android 2.2+(api level8),您可以使用ScaleGestureDetector.

你需要一个成员:

private ScaleGestureDetector mScaleDetector;

在你的构造函数(或onCreate())中添加:

mScaleDetector = new ScaleGestureDetector(context, new OnScaleGestureListener() {
    @Override
    public void onScaleEnd(ScaleGestureDetector detector) {
    }
    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) {
        return true;
    }
    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        Log.d(LOG_KEY, "zoom ongoing, scale: " + detector.getScaleFactor());
        return false;
    }
});

您重写onTouchEvent:

@Override
public boolean onTouchEvent(MotionEvent event) {
    mScaleDetector.onTouchEvent(event);
    return true;
}

如果您手动绘制视图,则在onScale()中可能会将比例因子存储在成员中,然后调用invalidate()并在onDraw()中绘制时使用比例因子.否则,您可以直接修改字体大小或onScale()中的字体大小.

Answer 3

我TextView使用本教程为我实现了一个缩放缩放.结果代码是这样的:

private GestureDetector gestureDetector;
private View.OnTouchListener gestureListener;

并在onCreate()中:

    // Zoom handlers
    gestureDetector = new GestureDetector(new MyGestureDetector());
    gestureListener = new View.OnTouchListener() {

        // We can be in one of these 2 states
        static final int NONE = 0;
        static final int ZOOM = 1;
        int mode = NONE;

        static final int MIN_FONT_SIZE = 10;
        static final int MAX_FONT_SIZE = 50;

        float oldDist = 1f;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            TextView textView = (TextView) findViewById(R.id.text);

            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_POINTER_DOWN:
                    oldDist = spacing(event);
                    Log.d(TAG, "oldDist=" + oldDist);
                    if (oldDist > 10f) {
                       mode = ZOOM;
                       Log.d(TAG, "mode=ZOOM" );
                    }
                    break;
                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    break;
                case MotionEvent.ACTION_MOVE:
                    if (mode == ZOOM) {
                        float newDist = spacing(event);
                        // If you want to tweak font scaling, this is the place to go.
                        if (newDist > 10f) {
                            float scale = newDist / oldDist;

                            if (scale > 1) {
                                scale = 1.1f;
                            } else if (scale < 1) {
                                scale = 0.95f;
                            }

                            float currentSize = textView.getTextSize() * scale;
                            if ((currentSize < MAX_FONT_SIZE && currentSize > MIN_FONT_SIZE)
                                    ||(currentSize >= MAX_FONT_SIZE && scale < 1)
                                    || (currentSize <= MIN_FONT_SIZE && scale > 1)) {
                                textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, currentSize);
                            }
                        }
                    }
                    break;
                }
            return false;
        }

魔术常数1.1和0.95是根据经验选择的(scale为此目的使用变量使我的TextView行为有点奇怪).

Answer 4

还有这个项目完成了这项工作,并为我完美工作:https: //github.com/chrisbanes/PhotoView