Android開發之GridView的使用（解讀谷歌官方API）

GridView將圖片顯示在二維可移動的網格裡，使用ListAdapter可以將Grid項目自動填充滿整個布局。下面我們根據官方文檔的例子來實現一下使用GridView，點擊視圖裡的圖片彈出圖片的position的效果。

首先在main.xml文件創建下列布局。

在MainAcitivity中，因為要使用setAdapter適配器加載數據，所以要先創建一個類繼承BaseAdapter

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    GridView gridview = (GridView) findViewById(R.id.gridview);
    gridview.setAdapter(new ImageAdapter(this));

    gridview.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView parent, View v, int position, long id) {
            Toast.makeText(HelloGridView.this, "" + position, Toast.LENGTH_SHORT).show();
        }
    });
}
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 null;
    }

    public long getItemId(int position) {
        return 0;
    }

    // create a new ImageView for each item referenced by the Adapter
    public View getView(int position, View convertView, ViewGroup parent) {
        ImageView imageView;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            imageView = new ImageView(mContext);
            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);
        } else {
            imageView = (ImageView) convertView;
        }

        imageView.setImageResource(mThumbIds[position]);
        return imageView;
    }

    // references to our images
    private Integer[] mThumbIds = {
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7,
            R.drawable.sample_0, R.drawable.sample_1,
            R.drawable.sample_2, R.drawable.sample_3,
            R.drawable.sample_4, R.drawable.sample_5,
            R.drawable.sample_6, R.drawable.sample_7
    };
}

添加以上代碼就已大功告成。setLayoutParams(ViewGroup.LayoutParams)，設置圖片大小。setScaleType(ImageView.ScaleType) 設置圖片顯示形式。setPadding(int, int, int, int)設置圖片的間距。如果視圖傳遞給getView()不是null,那麼使用當地的回收的convertView視圖對象進行初始化。