Android图片的缩放和拖动，,import andro

Android图片的缩放和拖动，,import andro

import android.app.Activity;  import android.content.Context;  import android.content.Intent;  import android.graphics.Bitmap;  import android.graphics.BitmapFactory;  import android.graphics.Matrix;  import android.graphics.PointF;  import android.graphics.RectF;  import android.os.Bundle;  import android.util.DisplayMetrics;  import android.util.FloatMath;  import android.view.MotionEvent;  import android.view.View;  import android.view.View.OnTouchListener;  import android.widget.ImageView;  import android.widget.Toast;  public class PhotoViewer extends Activity implements OnTouchListener {      private static final String TAG = "PhotoViewer";      public static final int RESULT_CODE_NOFOUND = 200;      Matrix matrix = new Matrix();      Matrix savedMatrix = new Matrix();      DisplayMetrics dm;      ImageView imgView;      Bitmap bitmap;      /** 最小缩放比例 */      float minScaleR = 0.5f;// 1.0f;      /** 最大缩放比例 */      static final float MAX_SCALE = 100f;// 10f;      /** 初始状态 */      static final int NONE = 0;      /** 拖动 */      static final int DRAG = 1;      /** 缩放 */      static final int ZOOM = 2;      /** 当前模式 */      int mode = NONE;      PointF prev = new PointF();      PointF mid = new PointF();      float dist = 1f;      @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          // 获取图片资源          bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.tchip);          setContentView(R.layout.activity_main);          imgView = (ImageView) findViewById(R.id.imageView1);// 获取控件          imgView.setImageBitmap(bitmap);// 填充控件          imgView.setOnTouchListener(this);// 设置触屏监听          dm = new DisplayMetrics();          getWindowManager().getDefaultDisplay().getMetrics(dm);// 获取分辨率          // minZoom();          center();          imgView.setImageMatrix(matrix);      }      // public void SureOnClick(View v)      // {      //      // }      /**      * 触屏监听      */      public boolean onTouch(View v, MotionEvent event) {          switch (event.getAction() &amp; MotionEvent.ACTION_MASK) {          // 主点按下          case MotionEvent.ACTION_DOWN:              savedMatrix.set(matrix);              prev.set(event.getX(), event.getY());              mode = DRAG;              break;          // 副点按下          case MotionEvent.ACTION_POINTER_DOWN:              dist = spacing(event);              // 如果连续两点距离大于10，则判定为多点模式              if (spacing(event) > 10f) {                  savedMatrix.set(matrix);                  midPoint(mid, event);                  mode = ZOOM;              }              break;          case MotionEvent.ACTION_UP:          case MotionEvent.ACTION_POINTER_UP:              mode = NONE;              // savedMatrix.set(matrix);              break;          case MotionEvent.ACTION_MOVE:              if (mode == DRAG) {                  matrix.set(savedMatrix);                  matrix.postTranslate(event.getX() - prev.x, event.getY()                          - prev.y);              } else if (mode == ZOOM) {                  float newDist = spacing(event);                  if (newDist > 10f) {                      matrix.set(savedMatrix);                      float tScale = newDist / dist;                      matrix.postScale(tScale, tScale, mid.x, mid.y);                  }              }              break;          }          imgView.setImageMatrix(matrix);          CheckView();          return true;      }      /**      * 限制最大最小缩放比例，自动居中      */      private void CheckView() {          float p[] = new float[9];          matrix.getValues(p);          setTitle("缩放级别：" + p[0] + "%");          if (mode == ZOOM) {              if (p[0] < minScaleR) {                  // Log.d("", "当前缩放级别:"+p[0]+",最小缩放级别:"+minScaleR);                  setTitle("缩放级别：" + p[0] + "%");                  matrix.setScale(minScaleR, minScaleR);              }              if (p[0] > MAX_SCALE) {                  // Log.d("", "当前缩放级别:"+p[0]+",最大缩放级别:"+MAX_SCALE);                  matrix.set(savedMatrix);              }          }          center();      }      /**      * 最小缩放比例，最大为100%      */      private void minZoom() {          minScaleR = Math.min(                  (float) dm.widthPixels / (float) bitmap.getWidth(),                  (float) dm.heightPixels / (float) bitmap.getHeight());          if (minScaleR < 1.0) {              matrix.postScale(minScaleR, minScaleR);          }      }      private void center() {          center(true, true);      }      /**      * 横向、纵向居中      */      protected void center(boolean horizontal, boolean vertical) {          Matrix m = new Matrix();          m.set(matrix);          RectF rect = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());          m.mapRect(rect);          float height = rect.height();          float width = rect.width();          float deltaX = 0, deltaY = 0;          if (vertical) {              // 图片小于屏幕大小，则居中显示。大于屏幕，上方留空则往上移，下方留空则往下移              int screenHeight = dm.heightPixels;              if (height < screenHeight) {                  //deltaY = (screenHeight - height) / 2 - rect.top;              } else              if (rect.top > 0) {                  deltaY = -rect.top;              } else if (rect.bottom < screenHeight) {                  deltaY = imgView.getHeight() - rect.bottom;              }          }          if (horizontal) {              int screenWidth = dm.widthPixels;              if (width < screenWidth) {                  deltaX = (screenWidth - width) / 2 - rect.left;              } else if (rect.left > 0) {                  deltaX = -rect.left;              } else if (rect.right < screenWidth) {                  deltaX = screenWidth - rect.right;              }          }          matrix.postTranslate(deltaX, deltaY);      }      /**      * 两点的距离      */      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);      }      /**      * 两点的中点      */      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);      }      public static class ImageViewOnClickListener implements              View.OnClickListener {          private Context context;          private String img_path;          public ImageViewOnClickListener(Context context, String img_path) {              this.img_path = img_path;              this.context = context;          }          @Override          public void onClick(View v) {              if (img_path != null) {                  // Toast.makeText(context, "TChip", Toast.LENGTH_SHORT).show();                  // Intent intent = new Intent(context, PhotoViewer.class);                  // intent.putExtra("PhotoPath", img_path);                  // context.startActivity(intent);              }          }      }  }