Android - 带有自定义 BaseAdapter 的 Gridview，创建 onclicklistener
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Android - Gridview with Custom BaseAdapter, create onclicklistener
提问by Christos Baziotis
I have created a gridview which displays the letters of the alphabet. I populate the gridview with a string array using a custom BaseAdapter.
我创建了一个 gridview 来显示字母表中的字母。我使用自定义 BaseAdapter 用字符串数组填充 gridview。
What i want to do is to be able to get the value (letter) of the clicked cell. In order to verify that it works, i have created a TextView and i want when the user clicks on an item (cell) to set the text of the TextView with the value of the selected cell
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，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
I have made an attempt which doesn't work. Here is my code:
我做了一个没有用的尝试。这是我的代码：
activity_main.xml
活动_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
单元格.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
主要活动
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
自定义网格适配器
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;
}
}
What am i doing wrong?
我究竟做错了什么？
Edit: It seems that the gridView.setOnItemClickListener(...); is not called/executed. I have changed it to this in order to check it and i see nothing in the logcat.
编辑：似乎 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");
}
});
采纳答案by gunar
The problem in your case is that the button is consuming the click and it doesn't get to GridView. I see two options:
您的情况的问题是该按钮正在消耗点击并且它没有到达 GridView。我看到两个选项：
- The easy one: in
cell.xmlhave these properties for yourButton:android:clickable="false"andandroid:focusable="false" - A grosso-modo: send the Activity as parameter to adapter and expose a public method from
MainActivity. If you think of re-using the adapter, then send an abstract type of activity or an interface.
- 最简单的一个：
cell.xml为您的Button:android:clickable="false"和android:focusable="false" - 大体模式：将 Activity 作为参数发送到适配器并从
MainActivity. 如果您考虑重用适配器，则发送抽象类型的活动或接口。
Something as:
东西如：
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]);
}
}
and in your adapter:
并在您的适配器中：
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;
}
}
回答by saiful103a
Actually for gridview setOnItemClickListener you are not doing anything wrong. It's the cell view that is creating the problem. Try changing cell-view button to a textview, it should work. Right now when you tap on an item in a gridview the item is not actually clicked because your cell-view button has it's own implementation of OnClickListener, and that is why setOnItemClickListener is not getting called.
实际上对于 gridview setOnItemClickListener 你没有做错任何事。造成问题的是单元格视图。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，当您点击 gridview 中的某个项目时，该项目实际上并未被单击，因为您的单元格视图按钮有自己的 OnClickListener 实现，这就是 setOnItemClickListener 没有被调用的原因。
回答by azerto00
You can use the setTag() adnd getTag() which allow you to put/get any type of object. So in the future, you will be able to pass anything (if you make the appropriate cast after)
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（如果你在之后进行了适当的转换）
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;
}
AND
和
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)));
}
});
