Question

我已按照此链接创建了一个网格视图

Android - Gridview with Custom BaseAdapter, get clicked View at position

工作正常。但我对cell.xml中的这两行感到困惑

android:clickable="false"
android:focusable="false"

这是假的，但是当我点击它时它正在工作，当我把它转为真时它不起作用。所以我很困惑，我有一些问题 -

•   Why they are needed? When we generally create button we don’t define these two attribute. But I when create a button for grid view cell why it is needed?
•   Why they work in reverse way? 
•   Is there any way to avoid these two line?

cell.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">

    <Button
        android:id="@+id/grid_item"
        android:layout_gravity="center"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="05"
        android:textSize="20sp"
        android:clickable="false"
        android:focusable="false"/>
    </Button>

</LinearLayout>

MainActivity.java

public class MainActivity extends Activity {

    private TextView text;
    private GridView gridView;
    private final String[] items = new String[]{"A", "B", "C", "D", "E", "F", "G", "H", "I", "J",
            "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        text = (TextView) findViewById(R.id.feedback);

        gridView = (GridView) this.findViewById(R.id.myGridView);
        CustomGridAdapter gridAdapter = new CustomGridAdapter(MainActivity.this, items);
        gridView.setAdapter(gridAdapter);
        gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                text.setText((String) (gridView.getItemAtPosition(position)));
                Log.i("ITEM_CLICKED", "" + (String) (gridView.getItemAtPosition(position)));
            }
        });

    }
}

CustomGridAdapter.xml

public class CustomGridAdapter extends BaseAdapter {

    private Context context;
    private String[] items;
    LayoutInflater inflater;

    public CustomGridAdapter(Context context, String[] items) {
        this.context = context;
        this.items = items;
        inflater = (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

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

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.cell, null);
        }
        Button button = (Button) convertView.findViewById(R.id.grid_item);
        button.setText(items[position]);

        return convertView;
    }

    @Override
    public int getCount() {
        return items.length;
    }

    @Override
    public Object getItem(int position) {
        return items[position];
    }

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

Answer 1

在大多数情况下，每个单元格的视图都没有任何可能消耗click事件的视图。因此，当您单击某一行时，GridView（或Listview）将调用onItemClickListener。

但是这里有一个可以默认点击的按钮。问题是GridView中的视图可以捕获click事件并阻止传播到gridview onItemClick事件。

因此，要避免按钮保留事件，您可以说它不应该是可点击的，具有属性clickable。

单元格中的可点击元素可用于为每行提供多个可点击区域。

困惑于android可点击，可聚焦的真假和他们的工作

1 个答案: