android - classcastexception - 尝试实现 toptoche searchablespinner
问题描述
在我以前的应用程序中，我使用了 toptoche 依赖项的可搜索微调器。（我以前的应用程序与这个非常相似，只是使用了 recyclerview 和 cardviews）所以我检查了我的代码，只是用 SearchableSpinner 替换了 Spinner 对象。但是，当我运行应用程序并按下 FAB 时（假设显示 cardview 时），我得到了一个 classcastexception。我在这里错过了什么吗？
错误
java.lang.ClassCastException: android.support.v7.widget.AppCompatSpinner cannot be cast to com.toptoche.searchablespinnerlibrary.SearchableSpinner
at com.app.supermarketaislefinder.ProductAdapter$ProductViewHolder.<init>(ProductAdapter.java:91)
at com.app.supermarketaislefinder.ProductAdapter.onCreateViewHolder(ProductAdapter.java:41)
at com.app.supermarketaislefinder.ProductAdapter.onCreateViewHolder(ProductAdapter.java:20)
at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:6685)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5869)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5752)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5748)
at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2232)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1559)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1519)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:614)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3812)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3529)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4082)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:948)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1855)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:443)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1655)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1513)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1426)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
at android.view.View.layout(View.java:13856)
at android.view.ViewGroup.layout(ViewGroup.java:4424)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1992)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1813)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1113)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4481)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
at android.view.Choreographer.doCallbacks(Choreographer.java:555)
at android.view.Choreographer.doFrame(Choreographer.java:525)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4867)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774)
at dalvik.system.NativeStart.main(Native Method)
ProductAdapter.java错误似乎在哪里
public class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductViewHolder> {
//this context we will use to inflate the layout
private Context mCtx;
private SearchableSpinner spinner;
//we are storing all the products in a list
private List<Product> productList;
//getting the context and product list with constructor
public ProductAdapter(Context mCtx, List<Product> productList) {
this.mCtx = mCtx;
this.productList = productList;
}
@Override
public ProductViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
//inflating and returning our view holder
LayoutInflater inflater = LayoutInflater.from(mCtx);
View view = inflater.inflate(R.layout.layout_products, null);
return new ProductViewHolder(view);
}
@Override
public void onBindViewHolder(ProductViewHolder holder, int position) {
//getting the product of the specified position
Product product = productList.get(position);
//binding the data with the viewholder views
//MyListAdapter adapter = new MyListAdapter(mCtx, R.layout.listrow, R.id.txtid, Product.spinnerItemsList);
//spinner.setAdapter(adapter);
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String> (mCtx, android.R.layout.simple_spinner_item, Product.getSpinnerItemsList());
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
holder.spinner.setAdapter(spinnerArrayAdapter);
}
@Override
public int getItemCount() {
return productList.size();
}
class ProductViewHolder extends RecyclerView.ViewHolder {
SearchableSpinner spinner;
EditText editText;
TextView textView5;
CheckBox checkBox;
public ProductViewHolder(View itemView) {
super(itemView);
spinner = itemView.findViewById(R.id.spinner);
editText = itemView.findViewById(R.id.editText);
textView5 = itemView.findViewById(R.id.textView5);
checkBox = itemView.findViewById(R.id.checkBox);
}
}
}
和我的活动代码供参考
public class create extends AppCompatActivity {
//a list to store all the products
List<Product> productList;
//the recyclerview
RecyclerView recyclerView;
Product mProduct;
private Map<String, String> numberItemValues = new HashMap<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.create);
//opens csv
InputStream inputStream = getResources().openRawResource(R.raw.shopitems);
CSVFile csvFile = new CSVFile(inputStream);
final List<String> mSpinnerItems = csvFile.read();
//getting the recyclerview from xml
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
//initializing the productlist
productList = new ArrayList<>();
///s/Di it work?
//I click the dropdown and the items show! I select an item, then i press fab to get another cardview
//I select an item from there , it shows
//i add another cardview then all the spinners are cleared?
//Hmm its because when the recyclerview item is out of the screen scope its recycled now you need to find a solution of
//storing the state of spinner for selected item
//i had a previous app which did exactly the same as this just without recyclerview and cardview. but with spinner i think
//i used sharedpreferences or something. i can have a look at my old code and see
//I will suggest you to make an array and then store the selected item by the index of the item in recyclerview
final SearchableSpinner spinner;
final EditText editText;
final CheckBox checkBox;
final TextView textView5;
spinner = findViewById(R.id.spinner);
editText = findViewById(R.id.editText);
checkBox = findViewById(R.id.checkBox);
textView5 = findViewById(R.id.textView5);
final ProductAdapter adapter = new ProductAdapter(this, productList);
//TODO FAB BUTTON
FloatingActionButton floatingActionButton =
(FloatingActionButton) findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
List<Product> mProductList = new ArrayList<>();
productList.add(mProduct);
if(adapter != null)
adapter.notifyDataSetChanged();
//Handle the empty adapter here
}
});
/* //TODO Add the spinner on item selected listener to get selected items
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
String currentItem = mSpinnerItems.get(position);
String aisleNumber = numberItemValues.get(currentItem);
//TODO you can use the above aisle number to add to your text view
//mTextviews.get(mTextviews.size() -1).setText(aisleNumber);
textView5.setText(aisleNumber);
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// do nothing
}
});*/
//setting adapter to recyclerview
recyclerView.setAdapter(adapter);
}
private class CSVFile {
InputStream inputStream;
public CSVFile(InputStream inputStream) {
this.inputStream = inputStream;
}
public List<String> read() {
// The problem with your adapter is solved now you need to do some work here its giving an error while reading the file
//why is it giving an error because it use to work fine before I added cardview and recyclerview
//Is the file there?
List<String> resultList = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
try {
String line;
while ((line = reader.readLine()) != null) {
String[] row = line.split(",");
//TODO I edited this part so that you'd add the values in our new hash map variable
numberItemValues.put(row[1], row[0]);
resultList.add(row[1]);
}
} catch (IOException e) {
Log.e("Main", e.getMessage());
} finally {
try {
inputStream.close();
} catch (IOException e) {
Log.e("Main", e.getMessage());
}
}
return resultList;
}
}
}
解决方案
问题是当您的 Spinner 对象存在于您的适配器中时，您正在 Activity 中执行操作，因此有两种方法，一种是从 Activity 内部的适配器访问该项目，一种是在 AdapterView 中实现该方法。
public class create extends AppCompatActivity {
//a list to store all the products
List<Product> productList;
//the recyclerview
RecyclerView recyclerView;
Product mProduct;
private Map<String, String> numberItemValues = new HashMap<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.create);
//opens csv
InputStream inputStream = getResources().openRawResource(R.raw.shopitems);
CSVFile csvFile = new CSVFile(inputStream);
final List<String> mSpinnerItems = csvFile.read();
//getting the recyclerview from xml
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
//initializing the productlist
productList = new ArrayList<>();
final ProductAdapter adapter = new ProductAdapter(this, productList);
//TODO FAB BUTTON
FloatingActionButton floatingActionButton =
(FloatingActionButton) findViewById(R.id.fab);
floatingActionButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
List<Product> mProductList = new ArrayList<>();
productList.add(mProduct);
if(adapter != null)
adapter.notifyDataSetChanged();
//Handle the empty adapter here
}
});
//setting adapter to recyclerview
recyclerView.setAdapter(adapter);
}
private class CSVFile {
InputStream inputStream;
public CSVFile(InputStream inputStream) {
this.inputStream = inputStream;
}
public List<String> read() {
// The problem with your adapter is solved now you need to do some work here its giving an error while reading the file
//why is it giving an error because it use to work fine before I added cardview and recyclerview
//Is the file there?
List<String> resultList = new ArrayList<String>();
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
try {
String line;
while ((line = reader.readLine()) != null) {
String[] row = line.split(",");
//TODO I edited this part so that you'd add the values in our new hash map variable
numberItemValues.put(row[1], row[0]);
resultList.add(row[1]);
}
} catch (IOException e) {
Log.e("Main", e.getMessage());
} finally {
try {
inputStream.close();
} catch (IOException e) {
Log.e("Main", e.getMessage());
}
}
return resultList;
}
}
}
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