android - 在android中检测没有触摸感的按钮

Question

我有 8 个按钮 我希望应用仅通过在屏幕上滚动而不是通过触摸来检测按钮？喜欢 Jelly bean 中的无障碍功能？我不确定如何称呼该功能？手势？运动感应？

这可能吗？我应该寻找什么？

谢谢!

Answer 1

默认情况下，Android 中的 UI 元素可通过滚动球、箭头键等获得焦点... View 具有 View.setOnFocusChangedListener 回调。您还可以通过编程方式将焦点设置在元素上。

我快速编写的一些示例代码，但没有测试。

float initialX = 0;
float initialY = 0;
int currentFocusedChild = 0;
List<View> children;

public void walkElements() {
    final LinearLayout mainLayout = (LinearLayout) findViewById(R.id.main_layout);
    children = mainLayout.getFocusables(View.FOCUS_FORWARD);
    mainLayout.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch(event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    initialX = event.getX();
                    initialY = event.getY();                        
                    break;
                case MotionEvent.ACTION_MOVE:
                    float diffX = event.getX() - initialX;
                    float diffY = event.getY() - initialY;

                    if(diffY > 0) {
                        if (currentFocusedChild < children.size() - 1) {
                            currentFocusedChild++;
                        }
                    } else {
                        if (currentFocusedChild > 0) {
                            currentFocusedChild--;
                        }
                    }
                    children.get(currentFocusedChild).setSelected(true);

                    //Sleep for a period of time so the selection is slow enough for the user.
                    Thread.sleep(300);
                    break;
                case MotionEvent.ACTION_UP:
                    children.get(currentFocusedChild).performClick();
                    break;
            }
            return false;
        }
    });

}