Android Open Source - Common-Library Touch Zoom Image View

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License

The source code is released under:
Apache License
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Java Source Code

package com.morgan.library.widget;
/* w ww.j a  va 2s. co  m*/
import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.view.animation.TranslateAnimation;
import android.widget.ImageView;

/**
 * ????????????????????
 * 
 * @author Morgan.Ji
 */
public class TouchZoomImageView extends ImageView {
  // ??????????
  static final int NONE = 0;
  // ????????????
  static final int DRAG = 1;
  // ????????????
  static final int ZOOM = 2;
  // mode??????????????
  private int mMode = NONE;

  // ??????
  static final int ZOOM_BIGGER = 3;
  // ???????
  static final int ZOOM_SMALLER = 4;

  // ???????????
  private float mBeforeLenght;
  // ???????????
  private float mAfterLenght;
  // ?????
  private float mZoomScale = 0.04f;

  // ???????????linearLayout???(?????????)
  private int mParentW;
  private int mParentH;
  private boolean mInitParentSize = false;

  // ?????
  private int mStartX;
  private int mStartY;

  // ???????
  private int mStopX;
  private int mStopY;
  // ????
  private TranslateAnimation mAnimation;
  // ?????????????????(???????????????????????????????????????????)
  private boolean mIsMulti;
  // ??????????????????
  private static final int MIN_LENGTH = 150;

  public TouchZoomImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.setPadding(0, 0, 0, 0);
    this.setScaleType(ScaleType.FIT_XY);
    this.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
        LayoutParams.WRAP_CONTENT));
  }

  // ??????2????????
  @SuppressLint("FloatMath")
  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);
  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    if (!mInitParentSize) {
      View parentView = (View) getParent();
      mParentW = parentView.getWidth();
      mParentH = parentView.getHeight();
      mInitParentSize = true;
    }
    // MotionEvent.ACTION_MASK????????
    switch (event.getAction() & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_DOWN:
      mMode = DRAG;
      // ????????????????????getX???????,?(int)event.getX()??,????????????????????????imageView????????.
      // ???????????????????????????????????getX()?????????????
      mStopX = (int) event.getRawX();
      mStopY = (int) event.getRawY();
      // ??????????????????????x?y?????start?stop??????????????????????????????????start?stop????????????????????getLeft???????
      mStartX = mStopX - this.getLeft();
      mStartY = mStopY - this.getTop();
      // ????
      mIsMulti = true;
      break;
    case MotionEvent.ACTION_POINTER_DOWN:
      // ?????????
      if (spacing(event) > 10f) {
        mMode = ZOOM;
        mBeforeLenght = spacing(event);
        // ??????????????????????????????????
        if (event.getX(1) < getWidth() && event.getX(1) > 0
            && event.getY(1) > 0 && event.getY(1) < getHeight()) {
          mIsMulti = true;
        } else {
          mIsMulti = false;
        }
      }
      break;
    case MotionEvent.ACTION_UP:
      // ?????????????????150????????????150????????
      while (getHeight() < MIN_LENGTH || getWidth() < MIN_LENGTH) {
        setScale(mZoomScale, ZOOM_BIGGER);
      }
      int disX = 0;
      int disY = 0;
      if (getHeight() <= mParentH) {
        if (this.getTop() < 0) {
          disY = getTop();
          this.layout(this.getLeft(), 0, this.getRight(),
              0 + this.getHeight());
        } else if (this.getBottom() > mParentH) {
          disY = getBottom() - mParentH;
          this.layout(this.getLeft(), mParentH - getHeight(),
              this.getRight(), mParentH);
        }
      } else {
        int Y1 = getTop();
        int Y2 = getHeight() - mParentH + getTop();
        if (Y1 > 0) {
          disY = Y1;
          this.layout(this.getLeft(), 0, this.getRight(),
              0 + this.getHeight());
        } else if (Y2 < 0) {
          disY = Y2;
          this.layout(this.getLeft(), mParentH - getHeight(),
              this.getRight(), mParentH);
        }
      }
      if (getWidth() <= mParentW) {
        if (this.getLeft() < 0) {
          disX = getLeft();
          this.layout(0, this.getTop(), 0 + getWidth(),
              this.getBottom());
        } else if (this.getRight() > mParentW) {
          disX = getWidth() - mParentW + getLeft();
          this.layout(mParentW - getWidth(), this.getTop(), mParentW,
              this.getBottom());
        }
      } else {
        int X1 = getLeft();
        int X2 = getWidth() - mParentW + getLeft();
        if (X1 > 0) {
          disX = X1;
          this.layout(0, this.getTop(), 0 + getWidth(),
              this.getBottom());
        } else if (X2 < 0) {
          disX = X2;
          this.layout(mParentW - getWidth(), this.getTop(), mParentW,
              this.getBottom());
        }
      }
      // ????disX?disY????????????????????????500???
      if (disX != 0 || disY != 0) {
        mAnimation = new TranslateAnimation(disX, 0, disY, 0);
        mAnimation.setDuration(500);
        this.startAnimation(mAnimation);
      }
      mMode = NONE;
      break;
    case MotionEvent.ACTION_POINTER_UP:
      mMode = NONE;
      break;
    case MotionEvent.ACTION_MOVE:
      if (mMode == DRAG) {
        // ???????????????????
        mStopX = (int) event.getRawX();
        mStopY = (int) event.getRawY();
        // ?????????????????????imageView????????????
        this.setPosition(mStopX - mStartX, mStopY - mStartY, mStopX
            + this.getWidth() - mStartX,
            mStopY - mStartY + this.getHeight());
      } else if (mMode == ZOOM && mIsMulti) {
        if (spacing(event) > 10f) {
          mAfterLenght = spacing(event);
          float gapLenght = mAfterLenght - mBeforeLenght;
          if (gapLenght == 0) {
            break;
          }
          // ???????????imageView?????70????????
          else if (Math.abs(gapLenght) > 5f && getWidth() > 70) {
            if (gapLenght > 0) {
              this.setScale(mZoomScale, ZOOM_BIGGER);
            } else {
              this.setScale(mZoomScale, ZOOM_SMALLER);
            }
            mBeforeLenght = mAfterLenght; // ?????????
          }
        }
      }
      break;
    }
    return true;
  }

  private void setScale(float temp, int flag) {

    if (flag == ZOOM_BIGGER) {
      // setFrame(left , top, right,bottom)???????????view???????????
      this.setFrame(this.getLeft() - (int) (temp * this.getWidth()),
          this.getTop() - (int) (temp * this.getHeight()),
          this.getRight() + (int) (temp * this.getWidth()),
          this.getBottom() + (int) (temp * this.getHeight()));
    } else if (flag == ZOOM_SMALLER) {
      this.setFrame(this.getLeft() + (int) (temp * this.getWidth()),
          this.getTop() + (int) (temp * this.getHeight()),
          this.getRight() - (int) (temp * this.getWidth()),
          this.getBottom() - (int) (temp * this.getHeight()));
    }
  }

  private void setPosition(int left, int top, int right, int bottom) {
    this.layout(left, top, right, bottom);
  }
}
Java Source Code List
