Android例子

<ImageView android:id="@+id/picture_view"

android:layout_width="fill_parent" android:layout_height="wrap_content"
android:maxHeight="300dip" android:maxWidth="300dip"

android:minHeight="300dip" android:minWidth="300dip"

android:scaleType="fitXY">
</ImageView>

 

 

public class PictureView extends Activity {
private ImageView mImageView;
private Button mButton01;
private Button mButton02;
private LinearLayout layout;
private LinearLayout layout1;
private ScrollView scrollView;
private int displayHeight;
private int displayWidth;
private Bitmap bmp;
private int id = 0;
private float scaleWidth = 1;
private float scaleHeight = 1;
@Override
public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
  setContentView(R.layout.picture_view);
  setTitle("图片名称带后缀名");
  layout = (LinearLayout) findViewById(R.id.picture_show);
  scrollView = (ScrollView) findViewById(R.id.picture_scroll);
  layout1 = (LinearLayout) findViewById(R.id.picture_area);
  mImageView = (ImageView) findViewById(R.id.picture_view);
  mImageView.setImageDrawable(getResources()
    .getDrawable(R.drawable.pop32));
  DisplayMetrics dm = new DisplayMetrics();
  getWindowManager().getDefaultDisplay().getMetrics(dm);
  displayWidth = dm.widthPixels;
  displayHeight = dm.heightPixels - 80;
  bmp = BitmapFactory.decodeResource(getResources(), R.drawable.pop32);
  mButton01 = (Button) findViewById(R.id.menu_button);
  mButton02 = (Button) findViewById(R.id.back_button);
  mButton01.setOnClickListener(new OnClickListener() {
   public void onClick(View v) {
    small();
   }
  });
  mButton02.setOnClickListener(new OnClickListener() {
   public void onClick(View v) {
    big();
   }
  });
}
/* 图片缩小的method */
private void small() {
  int bmpWidth = bmp.getWidth();
  int bmpHeight = bmp.getHeight();
  /* 设置图片缩小的比例 */
  double scale = 0.8;
  /* 计算出这次要缩小的比例 */
  scaleWidth = (float) (scaleWidth * scale);
  scaleHeight = (float) (scaleHeight * scale);
  /* 产生reSize后的Bitmap对象 */
  Matrix matrix = new Matrix();
  matrix.postScale(scaleWidth, scaleHeight);
  Bitmap resizeBmp = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight,
    matrix, true);
  if (id == 0) {
   /* 如果是第一次按，就删除原来默认的ImageView */
   layout1.removeView(mImageView);
  } else {
   /* 如果不是第一次按，就删除上次放大缩小所产生的ImageView */
   layout1.removeView((ImageView) findViewById(id));
  }
  /* 产生新的ImageView，放入reSize的Bitmap对象，再放入Layout中 */
  id++;
  ImageView imageView = new ImageView(PictureView.this);
  imageView.setId(id);
  imageView.setImageBitmap(resizeBmp);
  layout1.addView(imageView);
  setContentView(layout);
  /* 因为图片放到最大时放大按钮会disable，所以在缩小时把他重设为enable */
  mButton02.setEnabled(true);
}
/* 图片放大的method */
private void big() {
  int bmpWidth = bmp.getWidth();
  int bmpHeight = bmp.getHeight();
  /* 设置图片放大的比例 */
  double scale = 1.25;
  /* 计算这次要放大的比例 */
  scaleWidth = (float) (scaleWidth * scale);
  scaleHeight = (float) (scaleHeight * scale);
  /* 产生reSize后的Bitmap对象 */
  Matrix matrix = new Matrix();
  matrix.postScale(scaleWidth, scaleHeight);
  Bitmap resizeBmp = Bitmap.createBitmap(bmp, 0, 0, bmpWidth, bmpHeight,
    matrix, true);
  if (id == 0) {
   /* 如果是第一次按，就删除原来设置的ImageView */
   layout1.removeView(mImageView);
  } else {
   /* 如果不是第一次按，就删除上次放大缩小所产生的ImageView */
   layout1.removeView((ImageView) findViewById(id));
  }
  /* 产生新的ImageView，放入reSize的Bitmap对象，再放入Layout中 */
  id++;
  ImageView imageView = new ImageView(PictureView.this);
  imageView.setId(id);
  imageView.setImageBitmap(resizeBmp);
  layout1.addView(imageView);
  setContentView(layout);
  /* 如果再放大会超过屏幕大小，就把Button disable */
  if (scaleWidth * scale * bmpWidth > displayWidth
    || scaleHeight * scale * bmpHeight > displayHeight) {
   mButton02.setEnabled(false);
  }
}
}