多触点图片缩放
布局:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/relativeLayout1" android:layout_width="fill_parent" android:layout_height="fill_parent" > <Button android:id="@+id/zoom_in" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:text="zoom_in" /> <Button android:id="@+id/zoom_out" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_alignParentTop="true" android:text="zoom_out" /> <ScrollView android:id="@+id/imageContainer" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_below="@+id/zoom_in" android:fadingEdge="none" android:scrollbars="none" > <HorizontalScrollView android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_centerHorizontal="true" android:fadingEdge="none" android:scrollbars="none" > <ImageView android:id="@+id/imageView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:scaleType="matrix" /> </HorizontalScrollView> </ScrollView> </RelativeLayout>
程序代码:
package taokun.demo.MutilTouchDemo; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Matrix; import android.graphics.PointF; import android.os.Bundle; import android.util.FloatMath; import android.util.Log; import android.view.MotionEvent; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnTouchListener; import android.widget.Button; import android.widget.ImageView; public class MutilTouchDemoActivity extends Activity implements OnTouchListener, OnClickListener { private static final String TAG = "Touch" ; // These matrices will be used to move and zoom image Matrix matrix = new Matrix(); Matrix savedMatrix = new Matrix(); PointF start = new PointF(); PointF mid = new PointF(); float oldDist; private ImageView view; private Button zoomIn, zoomOut; //button zoom private float scaleWidth = 1; private float scaleHeight = 1; private Bitmap bmp, zoomedBMP; private int zoom_level = 0; private static final double ZOOM_IN_SCALE = 1.25;//放大系数 private static final double ZOOM_OUT_SCALE = 0.8;//缩小系数 // 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; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //放大按钮 zoomIn = (Button) findViewById(R.id.zoom_in); //缩小按钮 zoomOut = (Button) findViewById(R.id.zoom_out); zoomIn.setOnClickListener(this); zoomOut.setOnClickListener(this); view = (ImageView) findViewById(R.id.imageView); view.setOnTouchListener(this); //取得drawable中图片，放大，缩小，多点触摸的作用对象 bmp = BitmapFactory.decodeResource(MutilTouchDemoActivity.this.getResources(), R.drawable.splash); } public boolean onTouch(View v, MotionEvent event) { // Handle touch events here... ImageView view = (ImageView) v; // Handle touch events here... switch (event.getAction() & MotionEvent.ACTION_MASK) { //设置拖拉模式 case MotionEvent.ACTION_DOWN: savedMatrix.set(matrix); start.set(event.getX(), event.getY()); Log.d(TAG, "mode=DRAG" ); mode = DRAG; break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_POINTER_UP: mode = NONE; Log.d(TAG, "mode=NONE" ); break; //设置多点触摸模式 case MotionEvent.ACTION_POINTER_DOWN: oldDist = spacing(event); Log.d(TAG, "oldDist=" + oldDist); if (oldDist > 10f) { savedMatrix.set(matrix); midPoint(mid, event); mode = ZOOM; Log.d(TAG, "mode=ZOOM" ); } break; //若为DRAG模式，则点击移动图片 case MotionEvent.ACTION_MOVE: if (mode == DRAG) { matrix.set(savedMatrix); // 设置位移 matrix.postTranslate(event.getX() - start.x, event.getX() - start.x); } //若为ZOOM模式，则多点触摸缩放 else if (mode == ZOOM) { float newDist = spacing(event); Log.d(TAG, "newDist=" + newDist); if (newDist > 10f) { matrix.set(savedMatrix); float scale = newDist / oldDist; //设置缩放比例和图片中点位置 matrix.postScale(scale, scale, mid.x, mid.y); } } break; } // Perform the transformation view.setImageMatrix(matrix); return true; // indicate event was handled } //计算移动距离 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); } // 计算中点位置 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); } //放大，缩小按钮点击事件 @Override public void onClick(View v) { if(v == zoomIn){ enlarge(); }else if (v == zoomOut) { small(); } } //按钮点击缩小函数 private void small() { int bmpWidth = bmp.getWidth(); int bmpHeight = bmp.getHeight(); scaleWidth = (float) (scaleWidth * ZOOM_OUT_SCALE); scaleHeight = (float) (scaleHeight * ZOOM_OUT_SCALE); Matrix matrix = new Matrix(); matrix.postScale(scaleWidth, scaleHeight); zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix, true); view.setImageBitmap(zoomedBMP); } //按钮点击放大函数 private void enlarge() { try { int bmpWidth = bmp.getWidth(); int bmpHeight = bmp.getHeight(); scaleWidth = (float) (scaleWidth * ZOOM_IN_SCALE); scaleHeight = (float) (scaleHeight * ZOOM_IN_SCALE); Matrix matrix = new Matrix(); matrix.postScale(scaleWidth, scaleHeight); zoomedBMP = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight, matrix, true); view.setImageBitmap(zoomedBMP); } catch (Exception e) { } } }
