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java无法放大公交路线图

1 周，2 日 Questions & Answers

我有一张公交路线图作为图像。 使用缩放控制器，图像将缩小，但不会放大 请查看我的代码，让我知道要做的更改使其生效。。 我正在姜饼API 10上开发我的应用程序

import 安卓.os.Bundle;
import 安卓.app.Activity;
import 安卓.view.Menu;
import 安卓.view.View;
import 安卓.widget.ImageView;
import 安卓.widget.RelativeLayout;
import 安卓.widget.ZoomControls;

 public class Busmaps extends Activity {

ImageView img;
ZoomControls zoom;

 @Override
 public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.busmaps);

    img = (ImageView) findViewById(R.id.imageViewmaps1);
    zoom = (ZoomControls) findViewById(R.id.zoomControls1);

    zoom.setOnZoomInClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        int w = img.getWidth();
        int h = img.getHeight();

        RelativeLayout.LayoutParams params = 
            new RelativeLayout.LayoutParams(w + 50, h + 50);
        params.addRule(RelativeLayout.CENTER_IN_PARENT);

        img.setLayoutParams(params);
    }
  });

      zoom.setOnZoomOutClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        int w = img.getWidth();
        int h = img.getHeight();

        RelativeLayout.LayoutParams params = 
            new RelativeLayout.LayoutParams(w - 50, h - 50);
        params.addRule(RelativeLayout.CENTER_IN_PARENT);

        img.setLayoutParams(params);
    }
  });
  }

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.bus_map_zoom, menu);
    return true;
  }
  }

我的xml表示公交线路图像：-

<RelativeLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
  xmlns:tools="http://schemas.安卓.com/tools"
  安卓:layout_width="match_parent"
 安卓:layout_height="match_parent" >

  <ImageView
    安卓:id="@+id/imageViewmaps1"
    安卓:layout_width="wrap_content"
    安卓:layout_height="wrap_content"
    安卓:layout_centerHorizontal="true"
    安卓:layout_centerVertical="true"
    安卓:src="@drawable/map" />

  <ZoomControls
    安卓:id="@+id/zoomControls1"
    安卓:layout_width="wrap_content"
    安卓:layout_height="wrap_content"
    安卓:layout_alignParentBottom="true"
    安卓:layout_centerHorizontal="true"
     />

  </RelativeLayout>

我应该如何使我的缩放控制同时适用于放大和缩小


共 (2) 个答案

  1. # 1 楼答案

    请用以下内容替换放大和缩放侦听器：

    zoom.setOnZoomInClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        float x = img.getScaleX();
        float y = img.getScaleY();

        img.setScaleX((float) (x+1));
        img.setScaleY((float) (y+1));
    }
});

    zoom.setOnZoomOutClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub


        float x = img.getScaleX();
        float y = img.getScaleY();

        img.setScaleX((float) (x-1));
        img.setScaleY((float) (y-1));
    }
});
}

    另一种选择是在带有内置缩放控制器的Web视图中加载图像

    详情如下：

     String page = "<html><body><center><img src=\""+path to your image+"\"/></center></body></html>";
    webView.loadDataWithBaseURL("fake",page, "text/html", "UTF-8","");

    如果不想使用内置的web视图缩放控制器，则只需放置自己的按钮，并按如下方式在web视图上应用放大和缩小功能：

    webView.setInitialScale(ZOOM_LEVEL);
  2. # 2 楼答案 

    public class Busmap extends Activity implements OnTouchListener 
{
private static final String TAG = "Touch";
@SuppressWarnings("unused")
private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f;

// These matrices will be used to scale points of the image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();

// The 3 states (events) which the user is trying to perform
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;

// these PointF objects are used to record the point(s) the user is touching
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.busmaps);
    ImageView view = (ImageView) findViewById(R.id.imageViewmaps1);
    view.setOnTouchListener(this);
}

@Override
public boolean onTouch(View v, MotionEvent event) 
{
    ImageView view = (ImageView) v;
    view.setScaleType(ImageView.ScaleType.MATRIX);
    float scale;

    dumpEvent(event);
    // Handle touch events here...

    switch (event.getAction() & MotionEvent.ACTION_MASK) 
    {
        case MotionEvent.ACTION_DOWN:   // first finger down only
                                            savedMatrix.set(matrix);
                                            start.set(event.getX(), event.getY());
                                            Log.d(TAG, "mode=DRAG"); // write to LogCat
                                            mode = DRAG;
                                            break;

        case MotionEvent.ACTION_UP: // first finger lifted

        case MotionEvent.ACTION_POINTER_UP: // second finger lifted

                                            mode = NONE;
                                            Log.d(TAG, "mode=NONE");
                                            break;

        case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down

                                            oldDist = spacing(event);
                                            Log.d(TAG, "oldDist=" + oldDist);
                                            if (oldDist > 5f) {
                                                savedMatrix.set(matrix);
                                                midPoint(mid, event);
                                                mode = ZOOM;
                                                Log.d(TAG, "mode=ZOOM");
                                            }
                                            break;

        case MotionEvent.ACTION_MOVE:

                                            if (mode == DRAG) 
                                            { 
                                                matrix.set(savedMatrix);
                                                matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix  of points
                                            } 
                                            else if (mode == ZOOM) 
                                            { 
                                                // pinch zooming
                                                float newDist = spacing(event);
                                                Log.d(TAG, "newDist=" + newDist);
                                                if (newDist > 5f) 
                                                {
                                                    matrix.set(savedMatrix);
                                                    scale = newDist / oldDist; // setting the scaling of the
                                                                                // matrix...if scale > 1 means
                                                                                // zoom in...if scale < 1 means
                                                                                // zoom out
                                                    matrix.postScale(scale, scale, mid.x, mid.y);
                                                }
                                            }
                                            break;
    }

    view.setImageMatrix(matrix); // display the transformation on screen

    return true; // indicate event was handled
}



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);
}