[英]Custom Alert Dialog With RecyclerView
我正在使用RecyclerView
列出一些文本,現在我想這樣做,以便當用戶點擊文本時彈出一個自定義警報對話框。
到目前為止我已嘗試過這個但是得到一個NullPointerException; 這可能有什么問題?
public class CBAdapter extends RecyclerView.Adapter<CBAdapter.ViewHolder> {
List<AdapterData> mItems;
public CBAdapter() {
super();
mItems = new ArrayList<>();
AdapterData data = new AdapterData();
data.setTextOne("Many Bows");
mItems.add(data);
data = new AdapterData();
data.setTextOne("Pardon");
mItems.add(data);
data = new AdapterData();
data.setTextOne("Fall To Knees & Beg");
mItems.add(data);
data = new AdapterData();
data.setTextOne("Backflips");
mItems.add(data);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.test3, viewGroup, false);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, int i) {
AdapterData data = mItems.get(i);
viewHolder.textOne.setText(data.getTextOne());
}
@Override
public int getItemCount() {
return mItems.size();
}
class ViewHolder extends RecyclerView.ViewHolder{
public TextView textOne;
private Context context;
public ViewHolder(View itemView) {
super(itemView);
textOne = (TextView)itemView.findViewById(R.id.textView1);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.custom_dialog);
dialog.setTitle("Title");
TextView text = (TextView) dialog.findViewById(R.id.text);
text.setText("hello world");
ImageView image = (ImageView) dialog.findViewById(R.id.image);
image.setImageResource(R.drawable.ic_launcher);
Button dialogButton = (Button) dialog.findViewById(R.id.dialogButtonOK);
dialogButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dialog.dismiss();
}
});
dialog.show();
}
});
}
}
}
沒關系我忘了初始化我的上下文
context = itemView.getContext();
這不是您的查詢的答案,而是處理此方案的更好方法。
使用回調方法。
在您的活動中:
這將實現我們在Adapter
中的Adapter
。 在此示例中,將在用戶單擊RecyclerView
的項目時調用它。
public class MyActivity extends Activity implements AdapterCallback {
private MyAdapter mMyAdapter;
@Override
public void onMethodCallback() {
// Show your alert
}
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.mMyAdapter = new MyAdapter(this);
}
}
在您的適配器中:
在Activity中,我們啟動了我們的Adapter
並將其作為參數傳遞給構造函數。 這將啟動我們的回調方法接口。 您可以看到我們使用回調方法進行用戶點擊。
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private AdapterCallback mAdapterCallback;
public MyAdapter(Context context) {
try {
this.mAdapterCallback = ((AdapterCallback) context);
} catch (ClassCastException e) {
throw new ClassCastException("Activity must implement AdapterCallback.");
}
}
@Override
public void onBindViewHolder(final MyAdapter.ViewHolder viewHolder, final int i) {
// simple example, call interface here
// not complete
viewHolder.itemView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try {
mAdapterCallback.onMethodCallback();
} catch (ClassCastException exception) {
// do something
}
}
});
}
public static interface AdapterCallback {
void onMethodCallback();
}
}
禮貌: 從適配器調用Activity方法
final Dialog dialog = new Dialog(your_activity_context);
您正在使用context
是空 ,因此通過context
中ViewHolder
構造和CBAdapter構造也很喜歡,如下:
public class CBAdapter extends RecyclerView.Adapter<CBAdapter.ViewHolder> {
List<AdapterData> mItems;
Context context;
public CBAdapter(Context context) {
super();
this.context = context;
.....
}
並在ViewHolder類中
class ViewHolder extends RecyclerView.ViewHolder{
public TextView textOne;
private Context mcontext;
public ViewHolder(View itemView, Context mcontext) {
super(itemView);
this.mcontext = mcontext;
....
}
與問題沒有直接關系,雖然我求求你:不要在適配器內設置onClickListener-s!
這是應該如何做到的:
private class ItemDataHolder extends RecyclerView.ViewHolder implements View.OnLongClickListener{
private final String TAG = ItemDataHolder.class.getSimpleName();
/**
* Define view's elements
*/
/**
* Define object instance
*/
private Item mData;
// Constructor
public MessageDataHolder(View itemView) {
super(itemView);
/**
* Init elements
*/
itemView.setOnLongClickListener(this);
}
/**
* Method to handle long click on the item
* @param v View to handle click on
* @return
*/
@Override
public boolean onLongClick(View v) {
Log.v(TAG, "Long click fired!");
return false;
}
/**
* Function to update view's elements
* @param message Good data to be updated to
*/
public void bindData(Item message) {
mData = message;
/**
* Set values of views here
**/
}
}
希望我的答案能幫助別人寫出更好的代碼:)
寫這段代碼:
final Dialog dialog = new Dialog(CBAdapter.this);
代替
final Dialog dialog = new Dialog(context);
(要么)
context = CBAdapter.this; // Initialize context
希望這可以幫助。
快樂編碼:)
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