Android滑动控件.md

1.概述

最近写代码临时加了个功能主要是滑动选择的功能效果图如下:

2.代码

这里主要是用属性动画做的

<ImageButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_margin="@dimen/fab"
    android:background="@drawable/selector_add_fab"
    android:clickable="true" />

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <!-- 获得焦点但未按下时的背景图片 -->
    <item android:drawable="@drawable/add_fab" android:state_enabled="true" android:state_focused="false" android:state_pressed="false" />
    <item android:drawable="@drawable/add_fab_un" android:state_enabled="false" android:textColor="@color/white" />
    <!-- 按下时的背景图片 -->
    <item android:drawable="@drawable/add_fab_un" android:state_enabled="true" android:state_pressed="true" />
    <item android:drawable="@drawable/add_fab_un" android:state_enabled="true" android:state_focused="true" />

</selector>

private void setImageButtonTouch() {
    DisplayMetrics dm = getResources().getDisplayMetrics();
    screenWidth = dm.widthPixels;
    screenHeight = dm.heightPixels - DensityUtil.dpToPx(activity, 70);

    fb.setOnTouchListener(new View.OnTouchListener() {
        float lastX = 0;
        float lastY = 0;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            Log.d(TAG, "ontouch" + event.getActionMasked());
            switch (event.getActionMasked()) {
                case MotionEvent.ACTION_DOWN:
                    lastX = event.getRawX();
                    lastY = event.getRawY();
                    isDrag = false;
                    break;
                case MotionEvent.ACTION_MOVE:
                    //  不要直接用getX和getY,这两个获取的数据已经是经过处理的,容易出现图片抖动的情况
                    isDrag = true;
                    float distanceX = lastX - event.getRawX();
                    float distanceY = lastY - event.getRawY();

                    float nextY = fb.getY() - distanceY;
                    float nextX = fb.getX() - distanceX;

                    // 不能移出屏幕
                    if (nextY < 0) {
                        nextY = 0;
                    } else if (nextY > screenHeight - fb.getHeight()) {
                        nextY = screenHeight - fb.getHeight();
                    }
                    if (nextX < 0)
                        nextX = 0;
                    else if (nextX > screenWidth - fb.getWidth())
                        nextX = screenWidth - fb.getWidth();

                    // 属性动画移动
                    ObjectAnimator y = ObjectAnimator.ofFloat(fb, "y", fb.getY(), nextY);
                    ObjectAnimator x = ObjectAnimator.ofFloat(fb, "x", fb.getX(), nextX);

                    AnimatorSet animatorSet = new AnimatorSet();
                    animatorSet.playTogether(x, y);
                    animatorSet.setDuration(0);
                    animatorSet.start();

                    lastX = event.getRawX();
                    lastY = event.getRawY();
                    break;
                case MotionEvent.ACTION_UP:
                    if (!isDrag) {
                        startActivity(new Intent(activity, OtherActivity.class));
                    }
                    break;
            }
            return false;
        }
    });
}

3.踩坑

这里有个需要注意的是我一开始用的是

view.layout(上,下,左,右)设置位置,这样实际上是改变不了他的实际位置,只能改变视图,每次数据刷新或者点击原来位置都会恢复到原来的位置

         case MotionEvent.ACTION_MOVE:
               int dx = (int) event.getRawX() - lastX;
               int dy = (int) event.getRawY() - lastY;
               int l = v.getLeft() + dx;
               int b = v.getBottom() + dy;
               int r = v.getRight() + dx;
               int t = v.getTop() + dy;
               // 下面判断移动是否超出屏幕
                if (l < 0) {
                    l = 0;
                   r = l + v.getWidth();
                }
                if (t < 0) {
                  t = 0;
                    b = t + v.getHeight();
                }
                if (r > screenWidth) {
                    r = screenWidth;
                    l = r - v.getWidth();
                }
                if (b > screenHeight) {
                    b = screenHeight;
                   t = b - v.getHeight();
               }
                 v.layout(l, t, r, b);
                 lastX = (int) event.getRawX();
                 lastY = (int) event.getRawY();