android中手势操绘制片的平移、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