Android入门之Gallery（纯java）

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.*;
import android.widget.AdapterView.OnItemSelectedListener;

public class GalleryTest extends Activity {

private LinearLayout mainView = null; 	// 相对布局
private Gallery gallery = null; 		// gallery
private TextView tv=null;				//文本

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mainView_init();
setContentView(mainView);
}

/*mainView初始化*/
void mainView_init() {
mainView = new LinearLayout(this);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(-1, -1);
mainView.setLayoutParams(lp);
mainView.setOrientation(LinearLayout.VERTICAL);
tv_init();
gallery_init();
mainView.addView(gallery);
mainView.addView(tv);
}

/*tv初始化*/
void tv_init(){
tv=new TextView(this);
LinearLayout.LayoutParams lp=new LinearLayout.LayoutParams(-1,-2);
tv.setLayoutParams(lp);
tv.setTextSize(30);
tv.setText("这里显示图片选中响应");
tv.setGravity(Gravity.CENTER_HORIZONTAL);
}

/*gallery初始化*/
void gallery_init() {
gallery = new Gallery(this);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(-1, -2);
// lp.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
gallery.setLayoutParams(lp);
gallery.setSpacing(15);// 空隙
//
ImageAdapter ia = new ImageAdapter(this);
gallery.setAdapter(ia);
//
OnItemSelectedListener oisl = new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> arg0, View arg1,int arg2, long arg3) {
tv.setText("图片"+(arg2+1)+"被选中");
}
public void onNothingSelected(AdapterView<?> arg0) {
tv.setText("未选中任何图片");
}
};
gallery.setOnItemSelectedListener(oisl);
}

}

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

public class ImageAdapter extends BaseAdapter {

private Context context;
//图片源数组
private Integer[] imageInteger = { R.drawable.icon,R.drawable.p1,R.drawable.p2, R.drawable.p3,R.drawable.p4};

public ImageAdapter(Context c) {
context = c;
}

public int getCount() {
return imageInteger.length;
}

public Object getItem(int position) {
return position;
}

public long getItemId(int position) {
return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView = new ImageView(context);
imageView.setLayoutParams(new Gallery.LayoutParams(-2,120));
/*图片缩放处理，如果先设置了iamgeView的大小，则必须注意加载的图片大小不能超出，否则无法显示*/
Bitmap bm = BitmapFactory.decodeResource(context.getResources(),imageInteger[position]);
//原始尺寸
int width=bm.getWidth();
int height=bm.getHeight();
//缩放比例
if(height>120){
float scaleHeight=((float)120)/height;
float scaleWidth=scaleHeight;
// 创建操作图片用的matrix对象
Matrix matrix = new Matrix();
// 缩放图片动作
matrix.postScale(scaleWidth, scaleHeight);
//旋转图片 动作
//matrix.postRotate(45);
// 创建新的图片
Bitmap resizedBitmap = Bitmap.createBitmap(bm,0,0,width, height,matrix,true);
imageView.setImageBitmap(resizedBitmap);
}else{
imageView.setImageBitmap(bm);
}
imageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
return imageView;
}

}