Android GridView的使用

最新推荐文章于 2022-10-13 07:26:34 发布

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#android #imagelist #layout #resources #image #encoding

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本文详细介绍了如何在Android中使用GridView来展示图片。通过创建一个继承自BaseAdapter的ImageList类，并在主程序中设置GridView的适配器，实现图片的显示。点击监听器和选择监听器分别用于处理点击事件和选中状态。最后展示了包含GridView的XML布局文件。

Android的GridView控件用于把一系列的空间组织成一个二维的网格显示出来应用的比较多的就是组合图片显示下面我就详细讲一个例子

首先写一个类继承BaseAdapter

public class ImageList extends BaseAdapter { public Bitmap[] image; Activity activity; // construct public ImageList(Activity a) { activity = a; } @Override public int getCount() { // TODO Auto-generated method stub return image.length; } @Override public Object getItem(int position) { // TODO Auto-generated method stub return image[position]; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub ImageView imageView; if (convertView == null) { imageView = new ImageView(activity); imageView.setLayoutParams(new GridView.LayoutParams(50, 50));// 设置ImageView宽高 imageView.setAdjustViewBounds(false); imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); } else { imageView = (ImageView) convertView; } imageView.setImageBitmap(image[position]); return imageView; } public static Bitmap drawableToBitmap(Drawable drawable) { Bitmap bitmap = Bitmap .createBitmap( drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565); Canvas canvas = new Canvas(bitmap); drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight()); drawable.draw(canvas); return bitmap; } }

然后在主程序里

final GridView gv = (GridView) findViewById(R.id.grid); ImageList adapter = new ImageList(available.this); Resources res=getResources(); Bitmap bmp=BitmapFactory.decodeResource(res, R.drawable.logo); adapter.image=new Bitmap[20]; for(int i=0;i<=19;i++) { adapter.image[i]=bmp; } gv.setAdapter(adapter); gv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // TODO Auto-generated method stub Log.i("phb", arg2 + ""); Log.i("phbsel",gv.isFocused()+""); Intent i=new Intent(available.this, com.mobile.links.shop.mycx.shopcart.class); startActivity(i); } }); gv.setOnItemSelectedListener(new OnItemSelectedListener(){ @Override public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // TODO Auto-generated method stub Log.i("selected",arg2+""); tv.setText(arg2+":detail"); } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } });

其中onClick函数是判断被点击

而onSelect函数是判断被选中也就是获得焦点的imageview

这样我们就可以基于gridview来做一些应用了。

构建gridview的xml代码

<?xml version="1.0" encoding="utf-8"?> <LinearLayout android:id="@+id/relativelayout" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" > <GridView android:id="@+id/availgrid" android:layout_width="fill_parent" android:layout_height="wrap_content" android:numColumns="4" android:verticalSpacing="30dp" android:layout_centerHorizontal = "true" /> </LinearLayout>