Android - 带有自定义 BaseAdapter 的 Gridview，创建 onclicklistener [重复]

Question

我创建了一个显示字母表的网格视图。我使用自定义 BaseAdapter 用字符串数组填充 gridview。

我想要做的是能够获得点击单元格的值（字母）。为了验证它是否有效，我创建了一个 TextView 并且我希望当用户单击一个项目（单元格）时将 TextView 的文本设置为所选单元格的值

我做了一次失败的尝试。这是我的代码：

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    tools:ignore="MergeRootFrame" >

    <GridView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/myGridView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:numColumns="7" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Large Text"
        android:id="@+id/feedback"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

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:enabled="true"
        android:clickable="true">
    </Button>

</LinearLayout>

MainActivity

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

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;
    }
}

我做错了什么？

编辑：好像gridView.setOnItemClickListener(...);不被调用/执行。我已将其更改为此以进行检查，但我在 logcat 中看不到任何内容。

gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Log.i("ON_ITEM_CLICK_LISTENER", "item clicked");
            }
        });

Answer 1

在您的情况下，问题是按钮正在消耗点击并且它没有到达 GridView。我看到两个选项：

1. 最简单的：在cell.xml 中为您的Button 提供这些属性：android:clickable="false" 和android:focusable="false"
2. Agrosso-modo：将 Activity 作为参数发送给适配器，并从 MainActivity 公开一个公共方法。如果您考虑重用适配器，则发送抽象类型的活动或接口。

某事：

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);

    }

    public void itemClicked(int position) {
        text.setText(items[position]);
    }
}

在你的适配器中：

public class CustomGridAdapter extends BaseAdapter {

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

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

    public View getView(final 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]);
        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                context.itemClicked(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 2

实际上对于 gridview setOnItemClickListener 你没有做错任何事。这是造成问题的单元格视图。尝试将单元格视图按钮更改为文本视图，它应该可以工作。现在，当您在 gridview 中点击一个项目时，该项目实际上并没有被点击，因为您的单元格视图按钮有它自己的 OnClickListener 实现，这就是 setOnItemClickListener 没有被调用的原因。

Answer 3

您可以使用 setTag() 和 getTag() 来放置/获取任何类型的对象。 所以在未来，你将能够传递任何东西（如果你之后进行适当的演员表）

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]);
    convertView.setTag(items[position]); 
    return convertView;
}

与

gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            String str = (String) view.getTag();
            text.setText(str);
            Log.i("ITEM_CLICKED", "" + (String) (gridView.getItemAtPosition(position)));
        }
    });