6.1.5 GridView详解编辑

Android中的数据能够通过GridView类实现表格化展现，它也属于列表类型的控件，其继承关系如下：

java.lang.Object 

   ↳ android.view.View 

     ↳ android.view.ViewGroup 

       ↳ android.widget.AdapterView 

         ↳ android.widget.AbsListView 

           ↳ android.widget.GridView

GridView控件应用案例效果如图6-10所示。



图6-10 GridView控件使用效果图

程序代码请参考代码清单6-8：

【代码清单6-8】 chapter6_4/src/com/work/GridView_1.java

public class GridView_1 extends Activity {

 @Override

 public void onCreate(Bundle savedInstanceState) {

 super.onCreate(savedInstanceState);


 setContentView(R.layout.grid);


 GridView g = (GridView) findViewById(R.id.myGrid);

 g.setAdapter(new ImageAdapter(this));


 g.setOnItemSelectedListener(new OnItemSelectedListener() {

 public void onItemSelected(AdapterView<?> parent, View view,

 int position, long id) {

 Toast.makeText(GridView_1.this, "图片ID：" + mThumbIds[position],

 Toast.LENGTH_SHORT).show();

 }


 public void onNothingSelected(AdapterView<?> parent) {

 }

 });

 }


 private Integer[] mThumbIds = { R.drawable.yellowimage,

 R.drawable.redimage, R.drawable.icon, R.drawable.blueimage,

 R.drawable.photo1962, R.drawable.photo189, R.drawable.photo1803,

 R.drawable.photo1796, R.drawable.photo1732, R.drawable.photo1553,

 R.drawable.photo1537, R.drawable.photo1503, R.drawable.photo1453,

 R.drawable.photo1450, R.drawable.photo1447, R.drawable.photo1441,

 R.drawable.photo1433, R.drawable.photo1432, R.drawable.photo1431,

 R.drawable.photo1426, R.drawable.photo1425, R.drawable.photo1424,

 R.drawable.photo1423, R.drawable.photo1422, R.drawable.photo142,

 R.drawable.photo140, R.drawable.photo1220, R.drawable.photo1208,

 R.drawable.photo1207, R.drawable.photo101209, };


 public class ImageAdapter extends BaseAdapter {

 private Context mContext;

 public ImageAdapter(Context c) {

 mContext = c;

 }


 public int getCount() {

 return mThumbIds.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;

 if (convertView == null) {

 imageView = new ImageView(mContext);

 imageView.setLayoutParams(new GridView.LayoutParams(60, 60));

 imageView.setPadding(8, 8, 8,
;

 } else {

 imageView = (ImageView) convertView;

 }

 imageView.setImageResource(mThumbIds[position]);

 return imageView;

 }

 }

}

代码的关键是实现BaseAdapter适配器类——ImageAdapter，代码如下：

 public View getView(int position, View convertView, ViewGroup parent) {

 ImageView imageView;

 if (convertView == null) {

 imageView = new ImageView(mContext);

 imageView.setLayoutParams(new GridView.LayoutParams(60, 60));

 imageView.setPadding(8, 8, 8,
;

 } else {

 imageView = (ImageView) convertView;

 }

 imageView.setImageResource(mThumbIds[position]);

 return imageView;

 }

在convertView为null的时候实例化控件，imageView.setLayoutParams(new GridView.LayoutParams(60, 60)是设置一个单元格中图片大小是60×60像素。imageView.setPadding(8, 8, 8,
设定GridView的单元格与其中的图片之间上、下、左、右空白。

布局文件chapter6_4/res/layout/grid.xml：




    android:id="@+id/myGrid2"

 android:layout_width="fill_parent" 

 android:layout_height="fill_parent"

    android:verticalSpacing="10dp"    

    android:horiznotallow="10dp"

    android:numColumns="auto_fit"

    android:columnWidth="60dp"

    android:gravity="center"

/> 

android:verticalSpacing="10dp"是两行之间的边距，android:horiznotallow="10dp"是两列之间的边距。android:numColumns="auto_fit"GridView列数设置为自动，android:columnWidth="60dp"是每列的宽度，也就是项目的宽度。android:gravity="center"是居中。

                                                   出自《Android开发案例驱动教程》第六章