雙擊放大ImageView

我想在ImageView上實現縮放功能，類似於iOS上的內置照片應用程序（我沒有物理的Android設備來做出更合適的比喻）。捏到縮放會很好，但放大雙擊是必不可少的。雙擊放大ImageView

我試過一些示例代碼（例如http://android-journey.blogspot.com/2010/01/android-gestures.html），但由於某種原因，這對我不起作用;沒有一個事件處理程序觸發（我可能省略了一些簡單的事情？）。

有人能指出我正確的方向嗎？的minSdkVersion = 7和下面的佈局：

爲了排除故障時，我與機器人的應用中使用的示例代碼從上述鏈接未經修改的，在Android 2.3模擬器

<?xml version="1.0" encoding="utf-8"?> 
<ImageView 
xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:src="@drawable/android" 
    android:id="@+id/image" 
    />

來源

2011-01-31 Adam

???這些迴應沒有幫助。 – Adam 2011-01-31 16:57:54

根據應用的要求，你可能想考慮將圖像加載到webview中。這具有瀏覽器的所有功能（如果可用，捏放大縮小，雙擊縮放，覆蓋按鈕縮放/縮小。您只需加載帶有指向手機圖像的標籤的html。

來源

2011-01-31 18:23:13 runor49

這工作得很好。相關問題：我如何找到屏幕的大小（減去鉻）？我從URL加載圖像;返回的圖像的大小在URL中被指定爲參數。（我不能只使用WebViewObj.width（）和height（），因爲它們在我的Activity的onCreate（）中爲0。 – Adam 2011-01-31 20:33:57

我不確定你的意思。爲什麼你需要設置大小？如果您將其從網絡中拉出，則通過不設置屬性，它應該顯示爲1：1。 – runor49 2011-01-31 22:42:15

在這裏，我解釋並寫了變焦代碼，但不能雙擊，其變焦通過跨越圖像，試試這個，它的工作對我來說：

package com.example.myapp 

import android.content.Context; 
import android.graphics.Matrix; 
import android.graphics.PointF; 
import android.graphics.drawable.Drawable; 
import android.util.AttributeSet; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.ScaleGestureDetector; 
import android.view.View; 
import android.widget.ImageView; 

public class TouchImageView extends ImageView { 

Matrix matrix; 

// We can be in one of these 3 states 
static final int NONE = 0; 
static final int DRAG = 1; 
static final int ZOOM = 2; 
int mode = NONE; 

// Remember some things for zooming 
PointF last = new PointF(); 
PointF start = new PointF(); 
float minScale = 1f; 
float maxScale = 3f; 
float[] m; 

int viewWidth, viewHeight; 
static final int CLICK = 3; 
float saveScale = 1f; 
protected float origWidth, origHeight; 
int oldMeasuredWidth, oldMeasuredHeight; 

ScaleGestureDetector mScaleDetector; 

Context context; 

public TouchImageView(Context context) { 
    super(context); 
    sharedConstructing(context); 
} 

public TouchImageView(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    sharedConstructing(context); 
} 

private void sharedConstructing(Context context) { 
    super.setClickable(true); 
    this.context = context; 
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener()); 
    matrix = new Matrix(); 
    m = new float[9]; 
    setImageMatrix(matrix); 
    setScaleType(ScaleType.MATRIX); 

    setOnTouchListener(new OnTouchListener() { 

     @Override 
     public boolean onTouch(View v, MotionEvent event) { 
      mScaleDetector.onTouchEvent(event); 
      PointF curr = new PointF(event.getX(), event.getY()); 

      switch (event.getAction()) { 
       case MotionEvent.ACTION_DOWN: 
        last.set(curr); 
        start.set(last); 
        mode = DRAG; 
        break; 

       case MotionEvent.ACTION_MOVE: 
        if (mode == DRAG) { 
         float deltaX = curr.x - last.x; 
         float deltaY = curr.y - last.y; 
         float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale); 
         float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale); 
         matrix.postTranslate(fixTransX, fixTransY); 
         fixTrans(); 
         last.set(curr.x, curr.y); 
        } 
        break; 

       case MotionEvent.ACTION_UP: 
        mode = NONE; 
        int xDiff = (int) Math.abs(curr.x - start.x); 
        int yDiff = (int) Math.abs(curr.y - start.y); 
        if (xDiff < CLICK && yDiff < CLICK) 
         performClick(); 
        break; 

       case MotionEvent.ACTION_POINTER_UP: 
        mode = NONE; 
        break; 
      } 

      setImageMatrix(matrix); 
      invalidate(); 
      return true; // indicate event was handled 
     } 

    }); 
} 

public void setMaxZoom(float x) { 
    maxScale = x; 
} 

private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { 
    @Override 
    public boolean onScaleBegin(ScaleGestureDetector detector) { 
     mode = ZOOM; 
     return true; 
    } 

    @Override 
    public boolean onScale(ScaleGestureDetector detector) { 
     float mScaleFactor = detector.getScaleFactor(); 
     float origScale = saveScale; 
     saveScale *= mScaleFactor; 
     if (saveScale > maxScale) { 
      saveScale = maxScale; 
      mScaleFactor = maxScale/origScale; 
     } else if (saveScale < minScale) { 
      saveScale = minScale; 
      mScaleFactor = minScale/origScale; 
     } 

     if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight) 
      matrix.postScale(mScaleFactor, mScaleFactor, viewWidth/2, viewHeight/2); 
     else 
      matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY()); 

     fixTrans(); 
     return true; 
    } 
} 

void fixTrans() { 
    matrix.getValues(m); 
    float transX = m[Matrix.MTRANS_X]; 
    float transY = m[Matrix.MTRANS_Y]; 

    float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale); 
    float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale); 

    if (fixTransX != 0 || fixTransY != 0) 
     matrix.postTranslate(fixTransX, fixTransY); 
} 

float getFixTrans(float trans, float viewSize, float contentSize) { 
    float minTrans, maxTrans; 

    if (contentSize <= viewSize) { 
     minTrans = 0; 
     maxTrans = viewSize - contentSize; 
    } else { 
     minTrans = viewSize - contentSize; 
     maxTrans = 0; 
    } 

    if (trans < minTrans) 
     return -trans + minTrans; 
    if (trans > maxTrans) 
     return -trans + maxTrans; 
    return 0; 
} 

float getFixDragTrans(float delta, float viewSize, float contentSize) { 
    if (contentSize <= viewSize) { 
     return 0; 
    } 
    return delta; 
} 

@Override 
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
    viewWidth = MeasureSpec.getSize(widthMeasureSpec); 
    viewHeight = MeasureSpec.getSize(heightMeasureSpec); 

    // 
    // Rescales image on rotation 
    // 
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight 
      || viewWidth == 0 || viewHeight == 0) 
     return; 
    oldMeasuredHeight = viewHeight; 
    oldMeasuredWidth = viewWidth; 

    if (saveScale == 1) { 
     //Fit to screen. 
     float scale; 

     Drawable drawable = getDrawable(); 
     if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0) 
      return; 
     int bmWidth = drawable.getIntrinsicWidth(); 
     int bmHeight = drawable.getIntrinsicHeight(); 

     Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight); 

     float scaleX = (float) viewWidth/(float) bmWidth; 
     float scaleY = (float) viewHeight/(float) bmHeight; 
     scale = Math.min(scaleX, scaleY); 
     matrix.setScale(scale, scale); 

     // Center the image 
     float redundantYSpace = (float) viewHeight - (scale * (float) bmHeight); 
     float redundantXSpace = (float) viewWidth - (scale * (float) bmWidth); 
     redundantYSpace /= (float) 2; 
     redundantXSpace /= (float) 2; 

     matrix.postTranslate(redundantXSpace, redundantYSpace); 

     origWidth = viewWidth - 2 * redundantXSpace; 
     origHeight = viewHeight - 2 * redundantYSpace; 
     setImageMatrix(matrix); 
    } 
    fixTrans(); 
}

}

這是縮放類：現在在activity_main.xml文件中，將您的ImageView替換爲您的包名稱的類名稱，例如：

<ImageView 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:src="@drawable/android" 
    android:id="@+id/image"/>

與

<com.example.myapp.TouchImageView 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:src="@drawable/android" 
    android:id="@+id/image"/>

在你MainActivity：

TouchImageView fullImageView = (TouchImageView)findViewById(R.id.image); 
fullImageView.setMaxZoom(4f);

就是這樣。 :)

來源

2014-12-06 15:11:08

雙擊放大ImageView

回答

相關問題