Android如何实现控件的缩放移动功能
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1.简介
话不多说先来张效果图
控件缩放移动.gif
上面的gif中,依次进行了拖动——>触摸右上角放大,缩小——>触摸上方与右测边缘——>双指放大缩小。
2 使用步骤
2.1 布局。外层一个LinearLayout,里面一个自定义的控件DragScaleView,为了能够更清楚的看到控件的变化过程,就给控件加了一个灰色带虚线的边框bg_dashgap。
layout文件
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:id="@+id/root" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#80ce3d3a" android:gravity="center_horizontal" android:fitsSystemWindows="true"> <com.xxx.xxx.ui.DragScaleView android:id="@+id/hair_dv" android:src="@drawable/ic_sure" android:background="@drawable/bg_dashgap" android:adjustViewBounds="true" android:layout_marginLeft="50dp" android:layout_marginTop="10dp" android:layout_width="100dp" android:layout_height="120dp" android:clickable="true"/> </LinearLayout>
在drawable文件夹下的bg_dashgap.xml
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" > <!-- 圆角 --> <corners android:bottomLeftRadius="8dp" android:bottomRightRadius="8dp" android:radius="15dp" android:topLeftRadius="8dp" android:topRightRadius="8dp" /> <!-- 描边 --> <stroke android:dashGap="4dp" android:dashWidth="4dp" android:width="2dp" android:color="@color/my_gery" /> </shape>
2.2 自定义的控件
单指触摸:
当ACTION_DOWN时如果坐标为1.2.3.4四个区域,则对View进行相应的左上/右上/左下/右下拉伸;
当ACTION_DOWN时如果坐标为5.6.7.8四个区域,则分别对上/右/下/左四个方向进行拉伸;
当ACTION_DOWN时如果坐标为9这个区域,则对View进行移动;
双指触摸:
先计算出触摸时双指的距离,float oriDist=distance(event);
再得到双指离开屏幕的距离,float newDist =distance(event);
得到两者之间的比例 float scale = newDist / oriDist;
计算双指间距离的方法
/** * 计算两个手指间的距离 * @param event 触摸事件 * @return 放回两个手指之间的距离 */ private float distance(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return (float) Math.sqrt(x * x + y * y);//两点间距离公式 }
自定义的控件
onTouch(View v, MotionEvent event)的触摸事件中代码块
image.png
其他的关键地方,代码中都有比较详细的注释了。思路就是
触摸监听
判断不同情况---getDirection(v, (int) event.getX(), (int) event.getY())
计算得到新的oriLeft, oriTop, oriRight, oriBottom
重新绘制---v.layout(oriLeft, oriTop, oriRight, oriBottom)
3 DragScaleView 的完整代码
public class DragScaleView extends android.support.v7.widget.AppCompatImageView implements View.OnTouchListener { protected int screenWidth; protected int screenHeight; protected int lastX; protected int lastY; private int oriLeft; private int oriRight; private int oriTop; private int oriBottom; private int dragDirection; private static final int TOP = 0x15; private static final int LEFT = 0x16; private static final int BOTTOM = 0x17; private static final int RIGHT = 0x18; private static final int LEFT_TOP = 0x11; private static final int RIGHT_TOP = 0x12; private static final int LEFT_BOTTOM = 0x13; private static final int RIGHT_BOTTOM = 0x14; private static final int TOUCH_TWO = 0x21; private static final int CENTER = 0x19; private int offset = 0; //可超出其父控件的偏移量 protected Paint paint = new Paint(); private static final int touchDistance = 80; //触摸边界的有效距离 // 初始的两个手指按下的触摸点的距离 private float oriDis = 1f; /** * 初始化获取屏幕宽高 */ protected void initScreenW_H() { screenHeight = getResources().getDisplayMetrics().heightPixels - 40; screenWidth = getResources().getDisplayMetrics().widthPixels; } public DragScaleView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); setOnTouchListener(this); initScreenW_H(); } public DragScaleView(Context context, AttributeSet attrs) { super(context, attrs); setOnTouchListener(this); initScreenW_H(); } public DragScaleView(Context context) { super(context); setOnTouchListener(this); initScreenW_H(); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); paint.setColor(Color.GRAY); paint.setStrokeWidth(4.0f); paint.setStyle(Paint.Style.STROKE); } @Override public boolean onTouch(View v, MotionEvent event) { setBackgroundResource(R.drawable.bg_dashgap); int action = event.getAction()& MotionEvent.ACTION_MASK; if (action == MotionEvent.ACTION_DOWN) { oriLeft = v.getLeft(); oriRight = v.getRight(); oriTop = v.getTop(); oriBottom = v.getBottom(); lastY = (int) event.getRawY(); lastX = (int) event.getRawX(); dragDirection = getDirection(v, (int) event.getX(), (int) event.getY()); } if (action == MotionEvent.ACTION_POINTER_DOWN){ oriLeft = v.getLeft(); oriRight = v.getRight(); oriTop = v.getTop(); oriBottom = v.getBottom(); lastY = (int) event.getRawY(); lastX = (int) event.getRawX(); dragDirection = TOUCH_TWO; oriDis = distance(event); } // 处理拖动事件 delDrag(v, event, action); invalidate(); return false; } /** * 处理拖动事件 * * @param v * @param event * @param action */ protected void delDrag(View v, MotionEvent event, int action) { switch (action) { case MotionEvent.ACTION_MOVE: int dx = (int) event.getRawX() - lastX; int dy = (int) event.getRawY() - lastY; switch (dragDirection) { case LEFT: // 左边缘 left(v, dx); break; case RIGHT: // 右边缘 right(v, dx); break; case BOTTOM: // 下边缘 bottom(v, dy); break; case TOP: // 上边缘 top(v, dy); break; case CENTER: // 点击中心-->>移动 center(v, dx, dy); break; case LEFT_BOTTOM: // 左下 left(v, dx); bottom(v, dy); break; case LEFT_TOP: // 左上 left(v, dx); top(v, dy); break; case RIGHT_BOTTOM: // 右下 right(v, dx); bottom(v, dy); break; case RIGHT_TOP: // 右上 right(v, dx); top(v, dy); break; case TOUCH_TWO: //双指操控 float newDist =distance(event); float scale = newDist / oriDis; //控制双指缩放的敏感度 int distX = (int) (scale*(oriRight-oriLeft)-(oriRight-oriLeft))/50; int distY = (int) (scale*(oriBottom-oriTop)-(oriBottom-oriTop))/50; if (newDist>10f){//当双指的距离大于10时,开始相应处理 left(v, -distX); top(v, -distY); right(v, distX); bottom(v, distY); } break; } if (dragDirection != CENTER) { v.layout(oriLeft, oriTop, oriRight, oriBottom); } lastX = (int) event.getRawX(); lastY = (int) event.getRawY(); break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_POINTER_UP: dragDirection = 0; break; } } /** * 触摸点为中心->>移动 * * @param v * @param dx * @param dy */ private void center(View v, int dx, int dy) { int left = v.getLeft() + dx; int top = v.getTop() + dy; int right = v.getRight() + dx; int bottom = v.getBottom() + dy; if (left < -offset) { left = -offset; right = left + v.getWidth(); } if (right > screenWidth + offset) { right = screenWidth + offset; left = right - v.getWidth(); } if (top < -offset) { top = -offset; bottom = top + v.getHeight(); } if (bottom > screenHeight + offset) { bottom = screenHeight + offset; top = bottom - v.getHeight(); } Log.d("raydrag", left+" "+top+" "+right+" "+bottom+" "+dx); v.layout(left, top, right, bottom); } /** * 触摸点为上边缘 * * @param v * @param dy */ private void top(View v, int dy) { oriTop += dy; if (oriTop < -offset) { //对view边界的处理,如果子view达到父控件的边界,offset代表允许超出父控件多少 oriTop = -offset; } if (oriBottom - oriTop - 2 * offset < 200) { oriTop = oriBottom - 2 * offset - 200; } } /** * 触摸点为下边缘 * * @param v * @param dy */ private void bottom(View v, int dy) { oriBottom += dy; if (oriBottom > screenHeight + offset) { oriBottom = screenHeight + offset; } if (oriBottom - oriTop - 2 * offset < 200) { oriBottom = 200 + oriTop + 2 * offset; } } /** * 触摸点为右边缘 * * @param v * @param dx */ private void right(View v, int dx) { oriRight += dx; if (oriRight > screenWidth + offset) { oriRight = screenWidth + offset; } if (oriRight - oriLeft - 2 * offset < 200) { oriRight = oriLeft + 2 * offset + 200; } } /** * 触摸点为左边缘 * * @param v * @param dx */ private void left(View v, int dx) { oriLeft += dx; if (oriLeft < -offset) { oriLeft = -offset; } if (oriRight - oriLeft - 2 * offset < 200) { oriLeft = oriRight - 2 * offset - 200; } } /** * 获取触摸点flag * * @param v * @param x * @param y * @return */ protected int getDirection(View v, int x, int y) { int left = v.getLeft(); int right = v.getRight(); int bottom = v.getBottom(); int top = v.getTop(); if (x < touchDistance && y < touchDistance) { return LEFT_TOP; } if (y < touchDistance && right - left - x < touchDistance) { return RIGHT_TOP; } if (x < touchDistance && bottom - top - y < touchDistance) { return LEFT_BOTTOM; } if (right - left - x < touchDistance && bottom - top - y < touchDistance) { return RIGHT_BOTTOM; } if (x < touchDistance) { return LEFT; } if (y < touchDistance) { return TOP; } if (right - left - x < touchDistance) { return RIGHT; } if (bottom - top - y < touchDistance) { return BOTTOM; } return CENTER; } /** * 计算两个手指间的距离 * * @param event 触摸事件 * @return 放回两个手指之间的距离 */ private float distance(MotionEvent event) { float x = event.getX(0) - event.getX(1); float y = event.getY(0) - event.getY(1); return (float) Math.sqrt(x * x + y * y);//两点间距离公式 } }
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