是否有一种通用的方法来显示大图,并使用户能够放大、缩小和平移图像?

到目前为止,我找到了两种方法:

覆盖ImageView,对于这样一个常见的问题,这似乎有点太多了。 使用webview,但对整体布局的控制较少等等。


当前回答

我使用WebView和加载图像从内存通过

webview.loadUrl("file://...")

WebView处理所有的平移、缩放和滚动。如果你使用wrap_content, webview不会比图像大,也不会显示白色区域。 WebView更好的ImageView;)

其他回答

更新

我刚刚给TouchImageView一个新的更新。它现在包括双击缩放和抛除平移和捏缩放。下面的代码非常过时。你可以查看github项目以获得最新的代码。

使用

在项目中放置TouchImageView.java。这样就可以像 ImageView。例子:

TouchImageView img = (TouchImageView) findViewById(R.id.img);

如果你在xml中使用TouchImageView,那么你必须提供完整的包 名称,因为它是一个自定义视图。例子:

<com.example.touch.TouchImageView
    android:id="@+id/img”
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

注意:我已经删除了我之前的答案,其中包括一些非常旧的代码,现在直接链接到github上最新的代码。

ViewPager

如果你有兴趣把TouchImageView放在ViewPager中,请参考这个答案。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageDetail = (ImageView) findViewById(R.id.imageView1);
    imageDetail.setOnTouchListener(new View.OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            ImageView view = (ImageView) v;
            System.out.println("matrix=" + savedMatrix.toString());
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_DOWN:
                    savedMatrix.set(matrix);
                    startPoint.set(event.getX(), event.getY());
                    mode = DRAG;
                    break;
                case MotionEvent.ACTION_POINTER_DOWN:
                    oldDist = spacing(event);
                    if (oldDist > 10f) {
                        savedMatrix.set(matrix);
                        midPoint(midPoint, event);
                        mode = ZOOM;
                    }
                    break;
                case MotionEvent.ACTION_UP:
                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    break;
                case MotionEvent.ACTION_MOVE:
                    if (mode == DRAG) {
                        matrix.set(savedMatrix);
                        matrix.postTranslate(event.getX() - startPoint.x, event.getY() - startPoint.y);
                    } else if (mode == ZOOM) {
                        float newDist = spacing(event);
                        if (newDist > 10f) {
                            matrix.set(savedMatrix);
                            float scale = newDist / oldDist;
                            matrix.postScale(scale, scale, midPoint.x, midPoint.y);
                        }
                    }
                    break;
            }
            view.setImageMatrix(matrix);
            return true;

        }

        @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);
        }

        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);
        }
    });
}

和可绘制文件夹应该有bticn图像文件。 完美工作:)

This is a very late addition to this thread but I've been working on an image view that supports zoom and pan and has a couple of features I haven't found elsewhere. This started out as a way of displaying very large images without causing OutOfMemoryErrors, by subsampling the image when zoomed out and loading higher resolution tiles when zoomed in. It now supports use in a ViewPager, rotation manually or using EXIF information (90° stops), override of selected touch events using OnClickListener or your own GestureDetector or OnTouchListener, subclassing to add overlays, pan while zooming, and fling momentum.

它不打算作为ImageView的一般使用替代品,因此不扩展它,并且不支持显示来自资源的图像,只支持资产和外部文件。它需要SDK 10。

源代码在GitHub上,有一个示例说明了在ViewPager中的使用。

https://github.com/davemorrissey/subsampling-scale-image-view

In Response to Janusz original question, there are several ways to achieve this all of which vary in their difficulty level and have been stated below. Using a web view is good, but it is very limited in terms of look and feel and controllability. If you are drawing a bitmap from a canvas, the most versatile solutions that have been proposed seems to be MikeOrtiz's, Robert Foss's and/or what Jacob Nordfalk suggested. There is a great example for incorporating the android-multitouch-controller by PaulBourke, and is great for having the multi-touch support and alltypes of custom views.

就我个人而言,如果你只是简单地绘制一个画布到一个位图,然后在ImageView中显示它,并希望能够使用多点触摸缩放和移动,我发现MikeOrtiz的解决方案是最简单的。然而,出于我的目的,他提供的Git代码似乎只在他的TouchImageView自定义ImageView类是唯一的子类或提供布局参数时才能工作:

android:layout_height="match_parent"
android:layout_height="match_parent"

不幸的是,由于我的布局设计,我需要“wrap_content”为“layout_height”。当我把它改成这样的时候,图像在底部被裁剪了,我不能滚动或缩放到裁剪的区域。 所以我看了一下ImageView的源代码,看看Android是如何实现“onMeasure”的,并改变MikeOrtiz的以适应。

   @Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

  //**** ADDED THIS ********/////
      int  w = (int) bmWidth;
      int  h = (int) bmHeight;
     width = resolveSize(w, widthMeasureSpec);  
     height = resolveSize(h, heightMeasureSpec);
  //**** END ********///   

   // width = MeasureSpec.getSize(widthMeasureSpec);   // REMOVED
   // height = MeasureSpec.getSize(heightMeasureSpec); // REMOVED

    //Fit to screen.
    float scale;
    float scaleX =  (float)width / (float)bmWidth;
    float scaleY = (float)height / (float)bmHeight;

    scale = Math.min(scaleX, scaleY);
    matrix.setScale(scale, scale);
    setImageMatrix(matrix);
    saveScale = 1f;

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

    matrix.postTranslate(redundantXSpace, redundantYSpace);

    origWidth = width - 2 * redundantXSpace;
    origHeight = height - 2 * redundantYSpace;
   // origHeight = bmHeight;
    right = width * saveScale - width - (2 * redundantXSpace * saveScale);
    bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);

    setImageMatrix(matrix);
}

这里的resolveSize(int,int)是一个实用程序,用于将所需的大小与MeasureSpec施加的约束进行协调,其中:

参数:

 - size How big the view wants to be
 - MeasureSpec Constraints imposed by the parent

返回:

 - The size this view should be."

本质上提供了一种行为更类似于图像加载时的原始ImageView类。还可以进行更多的更改,以支持修改纵横比的各种屏幕。但现在我希望这能有所帮助。感谢MikeOrtiz的原始代码,做得很好。

你也可以试试http://code.google.com/p/android-multitouch-controller/

这个图书馆真的很棒,尽管一开始有点难以理解。