如何显示图像的缩放部分并将图像拖动到图像的左侧，右侧，顶部和底部

Question

我需要显示图像的缩放部分，图像应该在图像移动到左侧，右侧，顶部，底部被拖累（感动）。

我为此使用了imageview。

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"> 

    <ImageView android:layout_height="fill_parent" 
       android:layout_width="fill_parent" 
      android:id="@+id/imageView2"> 
    </ImageView> 

</LinearLayout> 

请帮忙。我怎样才能做到这一点？

感谢 乔蒂

Answer 1

试试这个..

1. Draw your image on canvas.. 

2. scale the canvas for zoom in - zoom put. 

编辑：试试这个..

import android.content.Context; 
    import android.graphics.Canvas; 
    import android.graphics.drawable.BitmapDrawable; 
    import android.util.AttributeSet; 
    import android.util.Log; 
    import android.view.MotionEvent; 
    import android.view.ScaleGestureDetector; 
    import android.view.View; 

    public class MyImageView extends View { 

    private static final int INVALID_POINTER_ID = -1; 

private Drawable mImage; 
private float mPosX; 
private float mPosY; 

private float mLastTouchX; 
private float mLastTouchY; 
private int mActivePointerId = INVALID_POINTER_ID; 

private ScaleGestureDetector mScaleDetector; 
private float mScaleFactor = 1.f; 

public MyImageView(Context context) { 
    this(context, null, 0); 
mImage = getResources().getDrawable(R.drawable.imagename); 

    mImage.setBounds(0, 0, mImage.getIntrinsicWidth(), mImage.getIntrinsicHeight()); 
} 

public MyImageView(Context context, AttributeSet attrs) { 
    this(context, attrs, 0); 
} 

public MyImageView(Context context, AttributeSet attrs, int defStyle) { 
    super(context, attrs, defStyle); 
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener()); 
} 

@Override 
public boolean onTouchEvent(MotionEvent ev) { 
    // Let the ScaleGestureDetector inspect all events. 
    mScaleDetector.onTouchEvent(ev); 

    final int action = ev.getAction(); 
    switch (action & MotionEvent.ACTION_MASK) { 
    case MotionEvent.ACTION_DOWN: { 
     final float x = ev.getX(); 
     final float y = ev.getY(); 

     mLastTouchX = x; 
     mLastTouchY = y; 
     mActivePointerId = ev.getPointerId(0); 
     break; 
    } 

    case MotionEvent.ACTION_MOVE: { 
     final int pointerIndex = ev.findPointerIndex(mActivePointerId); 
     final float x = ev.getX(pointerIndex); 
     final float y = ev.getY(pointerIndex); 

     // Only move if the ScaleGestureDetector isn't processing a gesture. 
     if (!mScaleDetector.isInProgress()) { 
      final float dx = x - mLastTouchX; 
      final float dy = y - mLastTouchY; 

      mPosX += dx; 
      mPosY += dy; 

      invalidate(); 
     } 

     mLastTouchX = x; 
     mLastTouchY = y; 

     break; 
    } 

    case MotionEvent.ACTION_UP: { 
     mActivePointerId = INVALID_POINTER_ID; 
     break; 
    } 

    case MotionEvent.ACTION_CANCEL: { 
     mActivePointerId = INVALID_POINTER_ID; 
     break; 
    } 

    case MotionEvent.ACTION_POINTER_UP: { 
     final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) 
       >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; 
     final int pointerId = ev.getPointerId(pointerIndex); 
     if (pointerId == mActivePointerId) { 
      // This was our active pointer going up. Choose a new 
      // active pointer and adjust accordingly. 
      final int newPointerIndex = pointerIndex == 0 ? 1 : 0; 
      mLastTouchX = ev.getX(newPointerIndex); 
      mLastTouchY = ev.getY(newPointerIndex); 
      mActivePointerId = ev.getPointerId(newPointerIndex); 
     } 
     break; 
    } 
    } 

    return true; 
} 

@Override 
public void onDraw(Canvas canvas) { 
    super.onDraw(canvas); 

    canvas.save(); 
    Log.d("DEBUG", "X: "+mPosX+" Y: "+mPosY); 
    canvas.translate(mPosX, mPosY); 
    canvas.scale(mScaleFactor, mScaleFactor); 
    mImage.draw(canvas); 
    canvas.restore(); 
} 

private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { 
    @Override 
    public boolean onScale(ScaleGestureDetector detector) { 
     mScaleFactor *= detector.getScaleFactor(); 

     // Don't let the object get too small or too large. 
     mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f)); 

     invalidate(); 
     return true; 
    } 
} 

} 

在您的活动调用这个，的setContentView（新MyImageView（本））;

编辑：zooming and dragging images using matrix in android为了缩放/调整图像看看我的答案How to load an image and resize it immediately to use later。

Answer 2

我想你可以使用自定义的视图，并在画布上绘制位图（左，上，右，下）。