android中手势操绘制片的平移、缩放、旋转

android中手势操作图片的平移、缩放、旋转

在网上搜到很多都是一样的版本，只有平移和缩放的功能。我在搜到的源代码基础上添加了旋转和边界检查的功能。

 代码主要分两部分，一个activity一个view，代码如下：

package com.example.touch;import android.app.Activity;import android.os.Bundle;public class TouchImageViewActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        TouchImageView img = new TouchImageView(this);        setContentView(img);    }}

package com.example.touch;import android.graphics.Bitmap;import android.graphics.Bitmap.Config;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Matrix;import android.graphics.PointF;import android.util.DisplayMetrics;import android.util.FloatMath;import android.view.MotionEvent;import android.widget.ImageView;public class TouchImageView extends ImageView {float x_down = 0;float y_down = 0;PointF start = new PointF();PointF mid = new PointF();float oldDist = 1f;float oldRotation = 0;Matrix matrix = new Matrix();Matrix matrix1 = new Matrix();Matrix savedMatrix = new Matrix();private static final int NONE = 0;private static final int DRAG = 1;private static final int ZOOM = 2;int mode = NONE;boolean matrixCheck = false;int widthScreen;int heightScreen;Bitmap gintama;public TouchImageView(TouchImageViewActivity activity) {super(activity);gintama = BitmapFactory.decodeResource(getResources(), R.drawable.gintama);DisplayMetrics dm = new DisplayMetrics();activity.getWindowManager().getDefaultDisplay().getMetrics(dm);widthScreen = dm.widthPixels;heightScreen = dm.heightPixels;matrix = new Matrix();}protected void onDraw(Canvas canvas) {canvas.save();canvas.drawBitmap(gintama, matrix, null);canvas.restore();}public boolean onTouchEvent(MotionEvent event) {switch (event.getAction() & MotionEvent.ACTION_MASK) {case MotionEvent.ACTION_DOWN:mode = DRAG;x_down = event.getX();y_down = event.getY();savedMatrix.set(matrix);break;case MotionEvent.ACTION_POINTER_DOWN:mode = ZOOM;oldDist = spacing(event);oldRotation = rotation(event);savedMatrix.set(matrix);midPoint(mid, event);break;case MotionEvent.ACTION_MOVE:if (mode == ZOOM) {matrix1.set(savedMatrix);float rotation = rotation(event) - oldRotation;float newDist = spacing(event);float scale = newDist / oldDist;matrix1.postScale(scale, scale, mid.x, mid.y);// 縮放matrix1.postRotate(rotation, mid.x, mid.y);// 旋轉matrixCheck = matrixCheck();if (matrixCheck == false) {matrix.set(matrix1);invalidate();}} else if (mode == DRAG) {matrix1.set(savedMatrix);matrix1.postTranslate(event.getX() - x_down, event.getY()- y_down);// 平移matrixCheck = matrixCheck();matrixCheck = matrixCheck();if (matrixCheck == false) {matrix.set(matrix1);invalidate();}}break;case MotionEvent.ACTION_UP:case MotionEvent.ACTION_POINTER_UP:mode = NONE;break;}return true;}private boolean matrixCheck() {float[] f = new float[9];matrix1.getValues(f);// 图片4个顶点的坐标float x1 = f[0] * 0 + f[1] * 0 + f[2];float y1 = f[3] * 0 + f[4] * 0 + f[5];float x2 = f[0] * gintama.getWidth() + f[1] * 0 + f[2];float y2 = f[3] * gintama.getWidth() + f[4] * 0 + f[5];float x3 = f[0] * 0 + f[1] * gintama.getHeight() + f[2];float y3 = f[3] * 0 + f[4] * gintama.getHeight() + f[5];float x4 = f[0] * gintama.getWidth() + f[1] * gintama.getHeight() + f[2];float y4 = f[3] * gintama.getWidth() + f[4] * gintama.getHeight() + f[5];// 图片现宽度double width = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));// 缩放比率判断if (width < widthScreen / 3 || width > widthScreen * 3) {return true;}// 出界判断if ((x1 < widthScreen / 3 && x2 < widthScreen / 3&& x3 < widthScreen / 3 && x4 < widthScreen / 3)|| (x1 > widthScreen * 2 / 3 && x2 > widthScreen * 2 / 3&& x3 > widthScreen * 2 / 3 && x4 > widthScreen * 2 / 3)|| (y1 < heightScreen / 3 && y2 < heightScreen / 3&& y3 < heightScreen / 3 && y4 < heightScreen / 3)|| (y1 > heightScreen * 2 / 3 && y2 > heightScreen * 2 / 3&& y3 > heightScreen * 2 / 3 && y4 > heightScreen * 2 / 3)) {return true;}return false;}// 触碰两点间距离private float spacing(MotionEvent event) {float x = event.getX(0) - event.getX(1);float y = event.getY(0) - event.getY(1);return FloatMath.sqrt(x * x + y * y);}// 取手势中心点private void midPoint(PointF point, MotionEvent event) {float x = event.getX(0) + event.getX(1);float y = event.getY(0) + event.getY(1);point.set(x / 2, y / 2);}// 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);}// 将移动，缩放以及旋转后的图层保存为新图片// 本例中沒有用到該方法，需要保存圖片的可以參考public Bitmap CreatNewPhoto() {Bitmap bitmap = Bitmap.createBitmap(widthScreen, heightScreen,Config.ARGB_8888); // 背景图片Canvas canvas = new Canvas(bitmap); // 新建画布canvas.drawBitmap(gintama, matrix, null); // 画图片canvas.save(Canvas.ALL_SAVE_FLAG); // 保存画布canvas.restore();return bitmap;}}

1楼zhang_andrew昨天 09:29

顶一下，这个方法正是我在做项目要用到的