Android触控基础:MotionEvent
2016-07-25 11:26
381 查看
原文章地址:http://blog.csdn.net/bigconvience/article/details/26611003
常见的动作常量:
public static final int ACTION_DOWN = 0;单点触摸动作
public static final int ACTION_UP = 1;单点触摸离开动作
public static final int ACTION_MOVE = 2;触摸点移动动作
public static final int ACTION_CANCEL = 3;触摸动作取消
public static final int ACTION_OUTSIDE = 4;触摸动作超出边界
public static final int ACTION_POINTER_DOWN = 5;多点触摸动作
public static final int ACTION_POINTER_UP = 6;多点离开动作
一些非touch事件:
public static final int ACTION_HOVER_MOVE = 7;
public static final int ACTION_SCROLL = 8;
public static final int ACTION_HOVER_ENTER = 9;
public static final int ACTION_HOVER_EXIT = 10;
下面的代码段能使用户在屏幕上拖动一个对象。它记录了初始点的位置,计算点移动的距离,并将对象移动到新的位置。它正确的处理了这种情况:当第一个手指把控件拖到一个位置,然后按下第二个手指,且第二个手指与同一个控件上。当用户抬起第一个手指时,控件不会跑到第二个手指的位置同时第二个手指可以继续拖动控件。
下面的代码段能使用户在屏幕上拖动一个对象。它记录了初始点的位置,计算点移动的距离,并将对象移动到新的位置。它正确的处理了这种情况:当第一个手指把控件拖到一个位置,然后按下第二个手指,且第二个手指与同一个控件上。当用户抬起第一个手指时,控件不会跑到第二个手指的位置同时第二个手指可以继续拖动控件。
[java] view
plain copy
// The ‘active pointer’ is the one currently moving our object.
private int mActivePointerId = INVALID_POINTER_ID;
@Override
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = MotionEventCompat.getActionMasked(ev);
switch (action) {
case MotionEvent.ACTION_DOWN: {
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float y = MotionEventCompat.getY(ev, pointerIndex);
// Remember where we started (for dragging)
mLastTouchX = x;
mLastTouchY = y;
// Save the ID of this pointer (for dragging)
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
break;
}
case MotionEvent.ACTION_MOVE: {
// Find the index of the active pointer and fetch its position
final int pointerIndex =
MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float y = MotionEventCompat.getY(ev, pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a gesture.
if (!mScaleDetector.isInProgress()) {
// Calculate the distance moved
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
// Remember this touch position for the next move event
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev, 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 = MotionEventCompat.getX(ev, newPointerIndex);
mLastTouchY = MotionEventCompat.getY(ev, newPointerIndex);
mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
}
break;
}
}
return true;
}
常见的动作常量:
public static final int ACTION_DOWN = 0;单点触摸动作
public static final int ACTION_UP = 1;单点触摸离开动作
public static final int ACTION_MOVE = 2;触摸点移动动作
public static final int ACTION_CANCEL = 3;触摸动作取消
public static final int ACTION_OUTSIDE = 4;触摸动作超出边界
public static final int ACTION_POINTER_DOWN = 5;多点触摸动作
public static final int ACTION_POINTER_UP = 6;多点离开动作
一些非touch事件:
public static final int ACTION_HOVER_MOVE = 7;
public static final int ACTION_SCROLL = 8;
public static final int ACTION_HOVER_ENTER = 9;
public static final int ACTION_HOVER_EXIT = 10;
下面的代码段能使用户在屏幕上拖动一个对象。它记录了初始点的位置,计算点移动的距离,并将对象移动到新的位置。它正确的处理了这种情况:当第一个手指把控件拖到一个位置,然后按下第二个手指,且第二个手指与同一个控件上。当用户抬起第一个手指时,控件不会跑到第二个手指的位置同时第二个手指可以继续拖动控件。
下面的代码段能使用户在屏幕上拖动一个对象。它记录了初始点的位置,计算点移动的距离,并将对象移动到新的位置。它正确的处理了这种情况:当第一个手指把控件拖到一个位置,然后按下第二个手指,且第二个手指与同一个控件上。当用户抬起第一个手指时,控件不会跑到第二个手指的位置同时第二个手指可以继续拖动控件。
[java] view
plain copy
// The ‘active pointer’ is the one currently moving our object.
private int mActivePointerId = INVALID_POINTER_ID;
@Override
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = MotionEventCompat.getActionMasked(ev);
switch (action) {
case MotionEvent.ACTION_DOWN: {
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float y = MotionEventCompat.getY(ev, pointerIndex);
// Remember where we started (for dragging)
mLastTouchX = x;
mLastTouchY = y;
// Save the ID of this pointer (for dragging)
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
break;
}
case MotionEvent.ACTION_MOVE: {
// Find the index of the active pointer and fetch its position
final int pointerIndex =
MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float y = MotionEventCompat.getY(ev, pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a gesture.
if (!mScaleDetector.isInProgress()) {
// Calculate the distance moved
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
// Remember this touch position for the next move event
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev, 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 = MotionEventCompat.getX(ev, newPointerIndex);
mLastTouchY = MotionEventCompat.getY(ev, newPointerIndex);
mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
}
break;
}
}
return true;
}
相关文章推荐
- Android 使用版本控制工具时添加忽略文件方式
- Android 使用Vitamio打造自己的万能播放器(3)――本地播放(主界面、播放列表)
- [置顶] Android 百度地图 SDK v3.0.0 (一)
- fir.im Weekly - 新开发时代,需要什么样的技术分享
- Android之AsyncTask异步任务——防止内存泄露
- Android简易画板:
- Android的IPC机制二
- java.lang.RuntimeException: Unable to instantiate application com.android.tools.fd.runtime.Boo
- AutoCompleteTextView和MultiAutoCompleteTextView
- Android 插入日程到系统日历要注意的3点
- 开发日记——手机安全卫士 Day06 2016-7-25 修改部分界面,增加了联系人搜索功能,完成部分黑名单功能
- ScrollView嵌套ListView冲突问题的最优解决方案
- Android跑马灯实现
- android 开发工具—AndroidStudio获取SHA1值
- android中的MVP模式
- Android Camera 使用小结
- android5.1系统修改源码实现隐藏底部状态栏、隐藏通知栏、隐藏上方状态栏、永不熄屏的方法
- Android 使用Vitamio打造自己的万能播放器(2)―― 手势控制亮度、音量、缩放
- 桌面小组件的简单介绍
- Android Studio 更新gradle插件