Android 拼接多张图片（拖拽，缩放）

效果：



view上的几个图片可单个的进行旋转，移动

然后放大的话 是全部放大

主要通过手势拦截去控制 view上的bitmap

不断地去刷新bitmap的多个参数 不断地去绘制

主要的 DrawingView

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import java.util.ArrayList;
import java.util.List;

public class DrawingView extends View {

private List<CustomBitmap> _bitmaps;
private Context _context;
private CustomBitmap _curCustomBitmap;//当前操作的图形

private Matrix currentMatrix = new Matrix();

private float oldDist;
private float newDist;
private float scale;

/**
* 模式 NONE：无 DRAG：拖拽. ZOOM:缩放
*
* @author zhangjia
*/
private enum MODE {
NONE, DRAG, ZOOM
}

/**
* 设置偏移
*/
public enum TYPE {
UP, DOWN, LEFT, RIGHT
}

private MODE mode = MODE.NONE;// 默认模式

public DrawingView(Context context) {
super(context);
this._context = context;
_bitmaps = new ArrayList<>();
}

public DrawingView(Context context, AttributeSet attrs) {
super(context, attrs);
this._context = context;
_bitmaps = new ArrayList<>();
}

public void addBitmap(CustomBitmap bitmap) {
_bitmaps.add(bitmap);
}

//设置偏移
public void setOffset(TYPE type) {
if (type == TYPE.UP) {
_curCustomBitmap.matrix.postTranslate(0, -1);
} else if (type == TYPE.DOWN) {
_curCustomBitmap.matrix.postTranslate(0, 1);
} else if (type == TYPE.LEFT) {
_curCustomBitmap.matrix.postTranslate(-1, 0);
} else if (type == TYPE.RIGHT) {
_curCustomBitmap.matrix.postTranslate(1, 0);
}
invalidate();
}

public List<CustomBitmap> getViews() {
return _bitmaps;
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setAntiAlias(true);

//画在后面的图显示在上面
for (CustomBitmap bitmap : _bitmaps) {
canvas.drawBitmap(bitmap.getBitmap(), bitmap.matrix, paint);
}
}

/**
* 计算两点之间的距离
*
* @param event
* @return
*/
public float distance(MotionEvent event) {
float dx = event.getX(1) - event.getX(0);
float dy = event.getY(1) - event.getY(0);
return (float) Math.sqrt(dx * dx + dy * dy);
}

/**
* 计算两点之间的中间点
*
* @param event
* @return
*/
public PointF mid(MotionEvent event) {
float midX = (event.getX(1) + event.getX(0)) / 2;
float midY = (event.getY(1) + event.getY(0)) / 2;
return new PointF(midX, midY);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:// 手指压下屏幕
mode = MODE.DRAG;
if (_curCustomBitmap == null && _bitmaps.size() > 0) {
_curCustomBitmap = _bitmaps.get(_bitmaps.size() - 1);
}

for (CustomBitmap bitmap : _bitmaps) {
float[] values = new float[9];
bitmap.matrix.getValues(values);
float globalX = values[Matrix.MTRANS_X];
float globalY = values[Matrix.MTRANS_Y];
float width = bitmap.scaleW;
float height = bitmap.scaleH;
float midX = globalX + width / 2;
float midY = globalY + height / 2;
PointF pointF = new PointF(midX, midY);
bitmap.midPoint = pointF;
}

for (CustomBitmap bitmap : _bitmaps) {
float[] values = new float[9];
bitmap.matrix.getValues(values);
float globalX = values[Matrix.MTRANS_X];
float globalY = values[Matrix.MTRANS_Y];
float width= bitmap.scaleW;
float height = bitmap.scaleH;

Rect rect = new Rect((int) globalX, (int) globalY, (int) (globalX + width), (int) (globalY + height));

//正常
if (event.getX() > rect.left && event.getX() < rect.right && event.getY() > rect.top && event.getY() < rect.bottom){
_curCustomBitmap = bitmap;
//                        KLog.e(_curCustomBitmap.getId()+" 正常");
change(true,event);
break;
}
//上下颠倒
else if(event.getX() < rect.left && event.getX() > rect.left-width && event.getY() < rect.top && event.getY() > rect.top-height){
_curCustomBitmap = bitmap;
//                        KLog.e(_curCustomBitmap.getId()+" 颠倒");
change(true,event);
break;
}
//右转
else if(event.getX() > rect.left-height && event.getX() < rect.left && event.getY() > rect.top && event.getY() < rect.top+width){
_curCustomBitmap = bitmap;
//                        KLog.e(_curCustomBitmap.getId()+" 右");
change(true,event);
break;
}
//左转
else if(event.getX() > rect.left && event.getX() < rect.left+height && event.getY() > rect.top-width && event.getY() <rect.top) {
_curCustomBitmap = bitmap;
//                        KLog.e(_curCustomBitmap.getId()+" 左");
change(true,event);
break;
}
}
change(false,event);
break;

case MotionEvent.ACTION_POINTER_DOWN:// 当屏幕上还有触点（手指），再有一个手指压下屏幕
mode = MODE.ZOOM;
oldDist = spacing(event);
_curCustomBitmap.oldRotation = rotation(event);
_curCustomBitmap.startDis = distance(event);
if (_curCustomBitmap.startDis > 10f) {
_curCustomBitmap.midPoint = mid(event);
currentMatrix.set(_curCustomBitmap.matrix);// 记录ImageView当前的缩放倍数
}
break;
case MotionEvent.ACTION_MOVE:// 手指在屏幕移动，该 事件会不断地触发
if (mode == MODE.DRAG) {
float dx = event.getX() - _curCustomBitmap.startPoint.x;// 得到在x轴的移动距离
float dy = event.getY() - _curCustomBitmap.startPoint.y;// 得到在y轴的移动距离
_curCustomBitmap.matrix.set(currentMatrix);// 在没有进行移动之前的位置基础上进行移动
_curCustomBitmap.matrix.postTranslate(dx, dy);
} else if (mode == MODE.ZOOM) {// 缩放与旋转
float endDis = distance(event);// 结束距离
_curCustomBitmap.rotation = rotation(event) - _curCustomBitmap.oldRotation;
if (endDis > 10f) {
scale = endDis / _curCustomBitmap.startDis;// 得到缩放倍数
_curCustomBitmap.matrix.set(currentMatrix);
_curCustomBitmap.matrix.postScale(scale, scale, _curCustomBitmap.midPoint.x, _curCustomBitmap.midPoint.y);
_curCustomBitmap.matrix.postRotate(_curCustomBitmap.rotation, _curCustomBitmap.midPoint.x, _curCustomBitmap.midPoint.y);
}
newDist = spacing(event);
if (newDist > oldDist + 1 || newDist < oldDist - 1) {
scaleAll(newDist / oldDist);
oldDist = newDist;
}
}
break;
case MotionEvent.ACTION_UP:// 手指离开屏
break;
case MotionEvent.ACTION_POINTER_UP:// 有手指离开屏幕,但屏幕还有触点（手指）
mode = MODE.NONE;
setWh(scale);
break;
}
invalidate();
return true;
}

/**
* 获取旋转角度
*/
private float rotation(MotionEvent event) {
double delta_x = (event.getX(0) - event.getX(1));
double delta_y = (event.getY(0) - event.getY(1));
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}

/**
* 缩放倍数
*
* @param event
* @return
*/
private float spacing(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);
}

private void scaleAll(float scale) {
for (CustomBitmap bit : _bitmaps) {
bit.matrix.postScale(scale, scale, bit.midPoint.x, bit.midPoint.y);
}
}

private void setWh(float scale) {
for (CustomBitmap bit : _bitmaps) {
bit.scaleW = (int) (bit.scaleW * scale);
bit.scaleH = (int) (bit.scaleH * scale);

float[] values = new float[9];
bit.matrix.getValues(values);
float globalX = values[Matrix.MTRANS_X];
float globalY = values[Matrix.MTRANS_Y];
float width= bit.scaleW;
float height = bit.scaleH;

Rect rect = new Rect((int) globalX, (int) globalY, (int) (globalX + width), (int) (globalY + height));

bit.x=rect.left;
bit.y=rect.top;
bit.scale=scale;
}
}

private void change(boolean isChanged,MotionEvent event){
//切换操作对象，只要把这个对象添加到栈底就行
if (isChanged) {
_bitmaps.remove(_curCustomBitmap);
_bitmaps.add(_curCustomBitmap);
}
currentMatrix.set(_curCustomBitmap.matrix);// 记录ImageView当前的移动位置
_curCustomBitmap.matrix.set(currentMatrix);
_curCustomBitmap.startPoint.set(event.getX(), event.getY());
postInvalidate();
}

}

用来装 bitmap 的类 CustomBitmap

import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;

import java.io.File;

public class CustomBitmap {
//Matrix.MSKEW_X 控制X坐标的线性倾斜系数
//Matrix.MSKEW_Y 控制Y坐标的线性倾斜系数
//Matrix.MTRANS_X//左上顶点X坐标
//Matrix.MTRANS_Y//左上顶点Y坐标
//Matrix.MSCALE_X//宽度缩放倍数
//Matrix.MSCALE_Y//高度缩放位数
private int id;//唯一标识，实际项目中可替换为url
public float startDis;// 开始距离
public PointF midPoint;// 中间点
public int scaleW;//缩放后的宽度
public int scaleH;//缩放后的高度
public float oldRotation = 0;
public float rotation = 0;
public PointF startPoint = new PointF();
public Matrix matrix = new Matrix();
public Bitmap bitmap;
public String name;
public int x;//顶点坐标
public int y;
public float scale;//缩放

public File file;
public String url;
public int imgId;

public CustomBitmap(Bitmap bitmap) {
this.bitmap = bitmap;
}

public Bitmap getBitmap() {
return bitmap;
}

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public void setMatrix(Matrix matrix) {
this.matrix = matrix;
}

}

Github 地址

参考：

Android 多点触控，多张图片拖拽，缩放，旋转

Rect简介

android 判断 某个点是否在View的区域内

2018.3.23更新：

参考：https://blog.csdn.net/qq_17766199/article/details/79466506