Android中实现Gallery 点击放大

图片放大的思路：
　　第一、可以通过Matrix对象来变换图像，在选择的时候放大，在失去焦点的时候，缩小到原来的大小。


double scale = 1.2;
int width = bm.getWidth();
int height = bm.getHeight();
Log.i("size:", width+"");
float scaleWidth = (float)(scale*width);
float scaleHeight = (float)(scale*height);
Log.i("size:", scaleWidth+"");
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
bm = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, true);

　　第二 、通过动画

<?xml version="1.0" encoding="utf-8"?>

<scale
xmlns:android="http://schemas.android.com/apk/res/android"

android:interpolator="@android:anim/decelerate_interpolator"

android:fromXScale="1"
android:toXScale="1.1"
android:fromYScale="1"
android:toYScale="1.1"

android:pivotX="50%"
android:pivotY="50%"
android:duration="500">

</scale>

　　第三、通过setLayoutParams

view.setLayoutParams(new Gallery.LayoutParams(150,150));
int mCounts = g.getCount() - 1;
if(position>0 && (position < mCounts)){
  g.getChildAt(position - 1).setLayoutParams(new Gallery.LayoutParams(136, 88));
  g.getChildAt(position + 1).setLayoutParams(new Gallery.LayoutParams(136, 88));
                                }
if(position == 0){
  g.getChildAt(position + 1).setLayoutParams(new Gallery.LayoutParams(136, 88));
                                }
if(position == mCounts){
  g.getChildAt(position - 1).setLayoutParams(new Gallery.LayoutParams(136, 88));
                                }

注释：其中(136, 88)是gallery中图片的大小，是在ImageAdapter里面设置的。(150,150)是选中图片放大后的大小，可以随便设置，只要跟(136, 88)区别就行了，是为了观察变化，我设置的是150而已。

　　第四 、通过动画和LayoutParam结合

gallery.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public
void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
ImageView v = (ImageView)arg1;
if(tempView != null && v.hashCode() != tempView.hashCode()){
tempView.setLayoutParams(new Gallery.LayoutParams(50,50));
}
v.startAnimation(toLarge);
tempView = v;
v.setLayoutParams(new Gallery.LayoutParams(60,60));
//
//v.setLayoutParams(new Gallery.LayoutParams(130,130));
tvName.setText(tempList.get(arg2).getPicName());
}
@Override
public
void onNothingSelected(AdapterView<?> arg0) {
tvName.setText("Nothing selected .");
}
});