如何使触摸事件视图调整大小 [英] How to make view resizable on touch event
本文介绍了如何使触摸事件视图调整大小的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
请参阅下图
我想通过拖动其角来改变视图中突出显示的形状..拖动边角应长方形它可以是任何arbitary形状后不necessory视图
I want to change the shape of highlighted view by dragging its corner.. not necessory the view after dragging the corner should be rectangle it can be any arbitary shape
如何才达到这个??
现在我已经做了4个角上的可移动触摸事件，但形状没有改变
now i have done the 4 corners movable on touch event but the shape is not changing
package com.assignment.DragDrop;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
public class DrawView extends View {
Point point1,point2,point3,point4;
private ColorBall[] colorballs = new ColorBall[4]; // array that holds the balls
private int balID = 0; // variable to know what ball is being dragged
Paint paint;
Canvas canvas;
public DrawView(Context context) {
super(context);
paint=new Paint();
setFocusable(true); //necessary for getting the touch events
canvas= new Canvas();
// setting the start point for the balls
point1 = new Point();
point1.x = 50;
point1.y = 20;
point2 = new Point();
point2.x = 150;
point2.y = 20;
point3 = new Point();
point3.x = 150;
point3.y = 120;
point4 = new Point();
point4.x = 50;
point4.y = 120;
// declare each ball with the ColorBall class
colorballs[0] = new ColorBall(context,R.drawable.bol_blauw, point1);
colorballs[1] = new ColorBall(context,R.drawable.bol_blauw, point2);
colorballs[2] = new ColorBall(context,R.drawable.bol_groen, point3);
colorballs[3] = new ColorBall(context,R.drawable.bol_geel, point4);
}
// the method that draws the balls
@Override protected void onDraw(Canvas canvas) {
//canvas.drawColor(0xFFCCCCCC); //if you want another background color
paint.setAntiAlias(true);
paint.setDither(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL);
paint.setStrokeJoin(Paint.Join.ROUND);
// mPaint.setStrokeCap(Paint.Cap.ROUND);
paint.setStrokeWidth(5);
canvas.drawPaint(paint);
paint.setColor(Color.WHITE);
canvas.drawRect(point1.x+25, point2.x, point3.x+25, point4.x, paint);
BitmapDrawable mBitmap;
mBitmap= new BitmapDrawable();
// canvas.drawBitmap(bitmap, left, top, paint)
// shade_region_between_points();
// canvas.drawLine(point1.x, point1.y, point2.x, point2.y, paint);
// canvas.drawLine(point1.x, point1.y, point4.x, point4.y, paint);
// canvas.drawLine(point4.x, point4.y, point3.x, point3.y, paint);
// canvas.drawLine(point2.x, point2.y, point3.x, point3.y, paint);
//draw the balls on the canvas
for (ColorBall ball : colorballs) {
canvas.drawBitmap(ball.getBitmap(), ball.getX(), ball.getY(), paint);
// canvas.drawLine(point1.x, point1.y, point2.x, point2.y, paint);
// canvas.drawRect(point1.x, point2.x, point3.x, point4.x, paint);
}
/*Drawable drawable = getResources().getDrawable(R.drawable.ic_launcher);
drawable.setBounds( point1.x+25, point2.x, point3.x+25, point4.x);
drawable.draw(canvas);*/
}
// events when touching the screen
public boolean onTouchEvent(MotionEvent event) {
int eventaction = event.getAction();
int X = (int)event.getX();
int Y = (int)event.getY();
switch (eventaction ) {
case MotionEvent.ACTION_DOWN: // touch down so check if the finger is on a ball
balID = 0;
for (ColorBall ball : colorballs) {
// check if inside the bounds of the ball (circle)
// get the center for the ball
int centerX = ball.getX() + 25;
int centerY = ball.getY() + 25;
paint.setColor(Color.CYAN);
// calculate the radius from the touch to the center of the ball
double radCircle = Math.sqrt( (double) (((centerX-X)*(centerX-X)) + (centerY-Y)*(centerY-Y)));
// canvas.drawLine(point1.x, point1.y, point2.x, point2.y, paint);
// if the radius is smaller then 23 (radius of a ball is 22), then it must be on the ball
if (radCircle < 23){
balID = ball.getID();
canvas.drawRect(point1.x, point2.x, point3.x, point4.x, paint);
invalidate();
break;
}
invalidate();
//canvas.drawRect(point1.x, point2.x, point3.x, point4.x, paint);
// check all the bounds of the ball (square)
//if (X > ball.getX() && X < ball.getX()+50 && Y > ball.getY() && Y < ball.getY()+50){
// balID = ball.getID();
// break;
//}
}
break;
case MotionEvent.ACTION_MOVE: // touch drag with the ball
// move the balls the same as the finger
if (balID > 0) {
try {
colorballs[balID-1].setX(X-25);
colorballs[balID-1].setY(Y-25);
// canvas.drawLine(point1.x, point1.y, point2.x, point2.y, paint);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
paint.setColor(Color.CYAN);
canvas.drawRect(point1.x, point2.x, point3.x, point4.x, paint);
invalidate();
}
break;
case MotionEvent.ACTION_UP:
// touch drop - just do things here after dropping
break;
}
// redraw the canvas
invalidate();
return true;
}
public void shade_region_between_points()
{
canvas.drawRect(point1.x, point2.x, point3.x, point4.x, paint);
}
}
我是从互联网这个code。
I got this code from internet.
这将能够移动的角落上的触摸事件，但形状不动...
this will able to move corners on touch event but the shape is not moving...
推荐答案
随着code是绘制矩形触摸基地。
Following code is to draw rectangle on touch base.
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import com.common.Utils;
import com.example.rectangleoverlay.R;
public class DrawView extends View {
Point point1, point3;
Point point2, point4;
/**
* point1 and point 3 are of same group and same as point 2 and point4
*/
int groupId = -1;
private ArrayList<ColorBall> colorballs = new ArrayList<ColorBall>();
// array that holds the balls
private int balID = 0;
// variable to know what ball is being dragged
Paint paint;
Canvas canvas;
public DrawView(Context context) {
super(context);
paint = new Paint();
setFocusable(true); // necessary for getting the touch events
canvas = new Canvas();
// setting the start point for the balls
point1 = new Point();
point1.x = 50;
point1.y = 20;
point2 = new Point();
point2.x = 150;
point2.y = 20;
point3 = new Point();
point3.x = 150;
point3.y = 120;
point4 = new Point();
point4.x = 50;
point4.y = 120;
// declare each ball with the ColorBall class
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point1));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point2));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point3));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point4));
}
public DrawView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public DrawView(Context context, AttributeSet attrs) {
super(context, attrs);
paint = new Paint();
setFocusable(true); // necessary for getting the touch events
canvas = new Canvas();
// setting the start point for the balls
point1 = new Point();
point1.x = 50;
point1.y = 20;
point2 = new Point();
point2.x = 150;
point2.y = 20;
point3 = new Point();
point3.x = 150;
point3.y = 120;
point4 = new Point();
point4.x = 50;
point4.y = 120;
// declare each ball with the ColorBall class
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point1));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point2));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point3));
colorballs.add(new ColorBall(context, R.drawable.gray_circle, point4));
}
// the method that draws the balls
@Override
protected void onDraw(Canvas canvas) {
// canvas.drawColor(0xFFCCCCCC); //if you want another background color
paint.setAntiAlias(true);
paint.setDither(true);
paint.setColor(Color.parseColor("#55000000"));
paint.setStyle(Paint.Style.FILL);
paint.setStrokeJoin(Paint.Join.ROUND);
// mPaint.setStrokeCap(Paint.Cap.ROUND);
paint.setStrokeWidth(5);
canvas.drawPaint(paint);
paint.setColor(Color.parseColor("#55FFFFFF"));
if (groupId == 1) {
canvas.drawRect(point1.x + colorballs.get(0).getWidthOfBall() / 2,
point3.y + colorballs.get(2).getWidthOfBall() / 2, point3.x
+ colorballs.get(2).getWidthOfBall() / 2, point1.y
+ colorballs.get(0).getWidthOfBall() / 2, paint);
} else {
canvas.drawRect(point2.x + colorballs.get(1).getWidthOfBall() / 2,
point4.y + colorballs.get(3).getWidthOfBall() / 2, point4.x
+ colorballs.get(3).getWidthOfBall() / 2, point2.y
+ colorballs.get(1).getWidthOfBall() / 2, paint);
}
BitmapDrawable mBitmap;
mBitmap = new BitmapDrawable();
// draw the balls on the canvas
for (ColorBall ball : colorballs) {
canvas.drawBitmap(ball.getBitmap(), ball.getX(), ball.getY(),
new Paint());
}
}
// events when touching the screen
public boolean onTouchEvent(MotionEvent event) {
int eventaction = event.getAction();
int X = (int) event.getX();
int Y = (int) event.getY();
switch (eventaction) {
case MotionEvent.ACTION_DOWN: // touch down so check if the finger is on
// a ball
balID = -1;
groupId = -1;
for (ColorBall ball : colorballs) {
// check if inside the bounds of the ball (circle)
// get the center for the ball
Utils.logd("Id : " + ball.getID());
Utils.logd("getX : " + ball.getX() + " getY() : " + ball.getY());
int centerX = ball.getX() + ball.getWidthOfBall();
int centerY = ball.getY() + ball.getHeightOfBall();
paint.setColor(Color.CYAN);
// calculate the radius from the touch to the center of the ball
double radCircle = Math
.sqrt((double) (((centerX - X) * (centerX - X)) + (centerY - Y)
* (centerY - Y)));
Utils.logd("X : " + X + " Y : " + Y + " centerX : " + centerX
+ " CenterY : " + centerY + " radCircle : " + radCircle);
if (radCircle < ball.getWidthOfBall()) {
balID = ball.getID();
Utils.logd("Selected ball : " + balID);
if (balID == 1 || balID == 3) {
groupId = 2;
canvas.drawRect(point1.x, point3.y, point3.x, point1.y,
paint);
} else {
groupId = 1;
canvas.drawRect(point2.x, point4.y, point4.x, point2.y,
paint);
}
invalidate();
break;
}
invalidate();
}
break;
case MotionEvent.ACTION_MOVE: // touch drag with the ball
// move the balls the same as the finger
if (balID > -1) {
Utils.logd("Moving Ball : " + balID);
colorballs.get(balID).setX(X);
colorballs.get(balID).setY(Y);
paint.setColor(Color.CYAN);
if (groupId == 1) {
colorballs.get(1).setX(colorballs.get(0).getX());
colorballs.get(1).setY(colorballs.get(2).getY());
colorballs.get(3).setX(colorballs.get(2).getX());
colorballs.get(3).setY(colorballs.get(0).getY());
canvas.drawRect(point1.x, point3.y, point3.x, point1.y,
paint);
} else {
colorballs.get(0).setX(colorballs.get(1).getX());
colorballs.get(0).setY(colorballs.get(3).getY());
colorballs.get(2).setX(colorballs.get(3).getX());
colorballs.get(2).setY(colorballs.get(1).getY());
canvas.drawRect(point2.x, point4.y, point4.x, point2.y,
paint);
}
invalidate();
}
break;
case MotionEvent.ACTION_UP:
// touch drop - just do things here after dropping
break;
}
// redraw the canvas
invalidate();
return true;
}
public void shade_region_between_points() {
canvas.drawRect(point1.x, point3.y, point3.x, point1.y, paint);
}
}
下面的类用于存储对象
Following class is used to store objects
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
public class ColorBall {
Bitmap bitmap;
Context mContext;
Point point;
int id;
static int count = 0;
public ColorBall(Context context, int resourceId, Point point) {
this.id = count++;
bitmap = BitmapFactory.decodeResource(context.getResources(),
resourceId);
mContext = context;
this.point = point;
}
public int getWidthOfBall() {
return bitmap.getWidth();
}
public int getHeightOfBall() {
return bitmap.getHeight();
}
public Bitmap getBitmap() {
return bitmap;
}
public int getX() {
return point.x;
}
public int getY() {
return point.y;
}
public int getID() {
return id;
}
public void setX(int x) {
point.x = x;
}
public void setY(int y) {
point.y = y;
}
}
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