ScreenShotView.java

package net.oschina.app.widget;

import net.oschina.app.AppConfig;
import net.oschina.app.R;
import net.oschina.app.common.UIHelper;
import net.oschina.app.ui.BaseActivity;
import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.os.Build;
import android.util.Log;
import android.view.Display;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;

/**
 * 
 * 实现截图功能的View
 * 
 * @author yeguozhong@yeah.net
 * 
 */
public class ScreenShotView extends View implements OnTouchListener {

	private Paint mGrayPaint;
	private Rect topRect;
	private Rect rightRect;
	private Rect bottomRect;
	private Rect leftRect;

	private int screenWidth;
	private int screeenHeight;

	private OnScreenShotListener mListener;
	private BaseActivity mContext;

	// 截图内框的坐标
	private int top, right, bottom, left;
	// 辅助变量，用于暂时保存内框坐标
	private int tmpLeft, tmpTop, tmpRight, tmpBottom;

	private int innerWidth, innerHeight;
	// 触摸屏幕前后坐标
	private int downX, downY, moveX, moveY;

	private final static int TOUCH_SELECT = 1; // 选择标识
	private final static int TOUCH_MOVE = 2; // 移动选区

	private int touchFlag = TOUCH_SELECT;

	private boolean isInMoveSelection; // 是否在移动选区内
	private boolean isInTopPullArea; // 上拉调整大小
	private boolean isInRightPullArea; // 右拉调整大小
	private boolean isInBottomPullArea;
	private boolean isInLeftPullArea;

	private int innnerClickCount = 0; // 选框内双击中的有效点击次数
	private int outterClickCount = 0; // 选框外双击的有效点击次数
	private long timeInterval; // 触碰事件间隔
	private long firstClickTime; // 第一次单击时刻
	private long secondClickTime; // 第二次单击时刻
	private long TouchDownTime; // 刚触碰的时刻
	private long TouchUpTime; // 触碰结束时刻
	private final static long VALID_CLICK_INTERVAL = 500; // 触摸down,up一下500毫秒以内为一次单击
	private final static long VALID_DOUBLE_CLICK_INTERNAL = 1000;// 两次单击之间时间距离

	private final static int VALID_PULL_DISTANCE = 30; // 有效拉大拉小距离

	private boolean isTimeToTip = false;
	private boolean isHide = false;

	public final static String TEMP_SHARE_FILE_NAME = AppConfig.DEFAULT_SAVE_IMAGE_PATH
			+ "_share_tmp.jpg";

	private static Bitmap bmDoubleClickTip;
	/**
	 * 监听截图完成
	 */
	public interface OnScreenShotListener {
		public void onComplete(Bitmap bm);
	}

	@SuppressLint("NewApi")
	public ScreenShotView(BaseActivity context, OnScreenShotListener listener) {
		super(context);

		mListener = listener;
		mContext = context;
		mContext.setAllowDestroy(false, this);

		Point p = getDisplaySize(context.getWindowManager().getDefaultDisplay());
		screenWidth = p.x;
		screeenHeight = p.y;

		mGrayPaint = new Paint();
		mGrayPaint.setARGB(100, 0, 0, 0);

		topRect = new Rect();
		rightRect = new Rect();
		bottomRect = new Rect();
		leftRect = new Rect();

		topRect.set(0, 0, screenWidth, screeenHeight);

		setOnTouchListener(this);
		
        if(bmDoubleClickTip==null){
        	bmDoubleClickTip = BitmapFactory.decodeStream(getResources().openRawResource(R.drawable._pointer));
        }
        
		UIHelper.ToastMessage(mContext, "请滑动手指确定选区!");
	}

	@SuppressLint("DrawAllocation")
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);

		canvas.drawRect(topRect, mGrayPaint);
		canvas.drawRect(rightRect, mGrayPaint);
		canvas.drawRect(bottomRect, mGrayPaint);
		canvas.drawRect(leftRect, mGrayPaint);

		if (isTimeToTip) {
			// 在中间位置出现提示
			innerWidth = right - left;
			innerHeight = bottom - top;
			int bmWidth = bmDoubleClickTip.getWidth();
			int bmHeight = bmDoubleClickTip.getHeight();
			int x = (int) (left + (innerWidth - bmWidth) * 0.5);
			int y = (int) (top + (innerHeight - bmHeight) * 0.5);
			canvas.drawBitmap(bmDoubleClickTip, x, y, null);
			isTimeToTip = false;
		}
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		// TODO Auto-generated method stub
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
	}

	@Override
	public boolean onTouch(View v, MotionEvent event) {
		int action = event.getAction();

		switch (action) {
		case MotionEvent.ACTION_DOWN:
			isTimeToTip = false;

			downX = (int) event.getX();
			downY = (int) event.getY();

			isInMoveSelection = isInSeletion(downX, downY);
			isInTopPullArea = isInTopPullArea(downX, downY);
			isInRightPullArea = isInRightPullArea(downX, downY);
			isInBottomPullArea = isInBottomPullArea(downX, downY);
			isInLeftPullArea = isInLeftPullArea(downX, downY);

			TouchDownTime = System.currentTimeMillis();
			break;
		case MotionEvent.ACTION_MOVE:
			isTimeToTip = false;
			moveX = (int) event.getX();
			moveY = (int) event.getY();
			if (touchFlag == TOUCH_SELECT) {
				tmpLeft = left = getMin(downX, moveX);
				tmpTop = top = getMin(downY, moveY);
				tmpRight = right = getMax(downX, moveX);
				tmpBottom = bottom = getMax(downY, moveY);

				isInMoveSelection = false;
			} else if (touchFlag == TOUCH_MOVE && isInMoveSelection) {
				int xDistance = moveX - downX;
				int yDistance = moveY - downY;
				decideCoordinate(xDistance, yDistance);
			} else if (touchFlag == TOUCH_MOVE && isInTopPullArea) {
				int yDistance = downY - moveY;
				int extremeY = (bottom - 2 * VALID_PULL_DISTANCE);
				top = (tmpTop - yDistance) < extremeY ? (tmpTop - yDistance)
						: extremeY;
			} else if (touchFlag == TOUCH_MOVE && isInRightPullArea) {
				int xDistance = moveX - downX;
				int extremeX = (left + 2 * VALID_PULL_DISTANCE);
				right = (tmpRight + xDistance) > extremeX ? (tmpRight + xDistance)
						: extremeX;
			} else if (touchFlag == TOUCH_MOVE && isInBottomPullArea) {
				int yDistance = downY - moveY;
				int extremeY = (top + 2 * VALID_PULL_DISTANCE);
				bottom = (tmpBottom - yDistance) > extremeY ? (tmpBottom - yDistance)
						: extremeY;
			} else if (touchFlag == TOUCH_MOVE && isInLeftPullArea) {
				int xDistance = downX - moveX;
				int extremeX = (right - 2 * VALID_PULL_DISTANCE);
				left = (tmpLeft - xDistance) < extremeX ? (tmpLeft - xDistance)
						: extremeX;
			}
			setInnerBorder(left, top, right, bottom);
			break;
		case MotionEvent.ACTION_UP:
		case MotionEvent.ACTION_CANCEL:

			if (touchFlag == TOUCH_SELECT) {
				touchFlag = TOUCH_MOVE;
			} else if (touchFlag == TOUCH_MOVE) {
				tmpLeft = left;
				tmpTop = top;
				tmpRight = right;
				tmpBottom = bottom;
			}

			if (isShouldShowTip() && isTimeToTip == false) {
				isTimeToTip = true;
				invalidate();
			}

			TouchUpTime = System.currentTimeMillis();
			timeInterval = TouchUpTime - TouchDownTime;

			// 选区内的双击则为截图，选区外的双击则为取消截图
			if (timeInterval < VALID_CLICK_INTERVAL && isInMoveSelection) {
				innnerClickCount = innnerClickCount + 1;
				if (innnerClickCount == 1) {
					firstClickTime = System.currentTimeMillis();
				} else if (innnerClickCount == 2) {
					secondClickTime = System.currentTimeMillis();
					if ((secondClickTime - firstClickTime) < VALID_DOUBLE_CLICK_INTERNAL) {
						isTimeToTip = false;
						mListener.onComplete(getCutImage());
						dismiss();
					}
					innnerClickCount = 0;
				}
			} else if (timeInterval < VALID_CLICK_INTERVAL
					&& !isInMoveSelection) {
				outterClickCount = outterClickCount + 1;
				if (outterClickCount == 1) {
					firstClickTime = System.currentTimeMillis();
				} else if (outterClickCount == 2) {
					secondClickTime = System.currentTimeMillis();
					if ((secondClickTime - firstClickTime) < VALID_DOUBLE_CLICK_INTERNAL) {
						isTimeToTip = false;
						dismiss();
					}
					outterClickCount = 0;
				}
			}
			break;
		default:
			break;
		}
		return true;
	}

	private int getMin(int x, int y) {
		return x > y ? y : x;
	}

	private int getMax(int x, int y) {
		return x > y ? x : y;
	}

	/**
	 * 是否在左拉动选区
	 * 
	 * @return
	 */
	private boolean isInLeftPullArea(int x, int y) {
		if (((left - VALID_PULL_DISTANCE) <= x && x < (left + VALID_PULL_DISTANCE))
				&& ((top + VALID_PULL_DISTANCE) < y && y < (bottom - VALID_PULL_DISTANCE))) {
			return true;
		}
		return false;
	}

	/**
	 * 是否在右拉动选区
	 * 
	 * @return
	 */
	private boolean isInRightPullArea(int x, int y) {
		if (((right - VALID_PULL_DISTANCE) <= x && x < (right + VALID_PULL_DISTANCE))
				&& ((top + VALID_PULL_DISTANCE) < y && y < (bottom - VALID_PULL_DISTANCE))) {
			return true;
		}
		return false;
	}

	/**
	 * 是否在上拉动选区
	 * 
	 * @return
	 */
	private boolean isInTopPullArea(int x, int y) {
		if (((left + VALID_PULL_DISTANCE) <= x && x < (right - VALID_PULL_DISTANCE))
				&& ((top - VALID_PULL_DISTANCE) < y && y < (top + VALID_PULL_DISTANCE))) {
			return true;
		}
		return false;
	}

	/**
	 * 是否在下拉动选区
	 * 
	 * @return
	 */
	private boolean isInBottomPullArea(int x, int y) {
		if (((left + VALID_PULL_DISTANCE) <= x && x < (right - VALID_PULL_DISTANCE))
				&& ((bottom - VALID_PULL_DISTANCE) < y && y < (bottom + VALID_PULL_DISTANCE))) {
			return true;
		}
		return false;
	}

	/**
	 * 判断触碰的点有没有在移动选区内
	 * 
	 * @param x
	 * @param y
	 * @return
	 */
	private boolean isInSeletion(int x, int y) {
		if ((left != 0 || right != 0 || top != 0 || bottom != 0)
				&& ((left + VALID_PULL_DISTANCE) <= x && x <= (right - VALID_PULL_DISTANCE))
				&& ((top + VALID_PULL_DISTANCE) <= y && y <= (bottom - VALID_PULL_DISTANCE))) {
			return true;
		}
		return false;
	}

	/**
	 * 判断是否应该出现提示
	 * 
	 * @return
	 */
	private boolean isShouldShowTip() {
		if ((right - left) > 100 && (bottom - top) > 100) {
			return true;
		}
		return false;
	}

	/**
	 * 决定内层选框的坐标
	 * 
	 * @param xDistance
	 * @param yDistance
	 */
	private void decideCoordinate(int xDistance, int yDistance) {
		innerWidth = right - left;
		innerHeight = bottom - top;
		// 决定左右坐标
		if ((tmpLeft + xDistance) < 0) {
			right = innerWidth;
			left = 0;
		} else if ((tmpRight + xDistance) > screenWidth) {
			left = screenWidth - innerWidth;
			right = screenWidth;
		} else {
			left = tmpLeft + xDistance;
			right = tmpRight + xDistance;
		}

		// 决定上下坐标
		if ((tmpTop + yDistance) < 0) {
			bottom = innerHeight;
			top = 0;
		} else if ((tmpBottom + yDistance) > screeenHeight) {
			top = screeenHeight - innerHeight;
			bottom = screeenHeight;
		} else {
			top = tmpTop + yDistance;
			bottom = tmpBottom + yDistance;
		}
	}

	/**
	 * 设置 内层的边框坐标
	 */
	private void setInnerBorder(int left, int top, int right, int bottom) {
		Log.i("com.example", "left:" + left + ",top:" + top + ",right:" + right
				+ ",bottom:" + bottom);
		topRect.set(0, 0, screenWidth, top);
		rightRect.set(right, top, screenWidth, bottom);
		bottomRect.set(0, bottom, screenWidth, screeenHeight);
		leftRect.set(0, top, left, bottom);
		this.invalidate();
	}

	/**
	 * 截取内层边框中的View.
	 */
	private Bitmap getCutImage() {
		View view = mContext.getWindow().getDecorView();
		Bitmap bmp = Bitmap.createBitmap(view.getWidth(), view.getHeight(),
				Bitmap.Config.ARGB_8888);
		Canvas canvas = new Canvas(bmp);
		view.draw(canvas);
		return imageCrop(bmp);
	}

	/**
	 * 裁剪图片
	 */
	private Bitmap imageCrop(Bitmap bitmap) {
		int x =  left<0?0:left;
		int y = top + getStatusHeight();
		int width = right- left;
		int height = bottom - top;
		if((width+x)>bitmap.getWidth()){
			width = bitmap.getWidth()-x;
		}
		if((y+height)>bitmap.getHeight()){
			height = bitmap.getHeight()-y;
		}
		return Bitmap.createBitmap(bitmap,x,y,width,height , null, false);
	}

	/**
	 * 返回状态栏的高度
	 * 
	 * @return
	 */
	private int getStatusHeight() {
		Rect frame = new Rect();
		mContext.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
		return frame.top;
	}

	/**
	 * 注销该view
	 */
	private void dismiss() {
		isHide = true;
		mGrayPaint.setARGB(0, 0, 0, 0);
		setOnTouchListener(null);
		mContext.setAllowFullScreen(true);
		invalidate();
	}

	/**
	 * 获取不同设备的宽高
	 * @param display
	 * @return
	 */
	@SuppressLint("NewApi")
	private static Point getDisplaySize(final Display display) {
		final Point point = new Point();
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
			display.getSize(point);
		} else {
			point.x = display.getWidth();
			point.y = display.getHeight();
		}
		return point;
	}

	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if (keyCode == KeyEvent.KEYCODE_BACK && isHide == false) {
			mContext.setAllowDestroy(false);
			dismiss();
		} else if ((keyCode == KeyEvent.KEYCODE_BACK && isHide == true)) {
			mContext.setAllowDestroy(true);
		}
		return false;
	}
}