自定义适配器存在问题。我无法显示listview。当我运行应用程序时它停止运行。 请看下面的代码。
提前谢谢
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
// Hashmap for ListView
productsList = new ArrayList<>();
productitems=new ArrayList<String>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
pitems=new ArrayList<>();
ListView lv=(ListView) findViewById(R.id.list);
lv.setAdapter(myCustomAdapter);
// on seleting single product
// launching Edit Product Screen
}
// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AllProductsActivity.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
String price = c.getString(TAG_PRICE);
String av = c.getString(TAG_AV);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
map.put(TAG_PRICE,price);
map.put(TAG_AV, av);
productitems.add(id);
productitems.add(name);
productitems.add(price);
productitems.add(av);
pitems.add(productitems);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
Intent i = new Intent(getApplicationContext(),
NewCActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
myCustomAdapter=new MyCustomAdapter(AllProductsActivity.this, pitems);
}
});
}
}
}
public class MyCustomAdapter extends BaseAdapter {
private Context context_;
private ArrayList<ArrayList<String>> productitems;
private int quantity = 1;
public MyCustomAdapter(Context context, ArrayList<ArrayList<String>> productitems) {
this.productitems=productitems;
this.context_ = context;
}
@Override
public int getCount() {
return productitems.size();
}
@Override
public Object getItem(int position) {
return productitems.get(position).get(0);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
LayoutInflater mInflater = (LayoutInflater)
context_.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
convertView = mInflater.inflate(R.layout.list_item, null);
}
TextView id = (TextView) convertView.findViewById(R.id.pid);
TextView name = (TextView) convertView.findViewById(R.id.name);
TextView price = (TextView) convertView.findViewById(R.id.price);
TextView av = (TextView) convertView.findViewById(R.id.av);
Button plus = (Button) convertView.findViewById(R.id.plus);
Button minus = (Button) convertView.findViewById(R.id.minus);
TextView qnt = (TextView) convertView.findViewById(R.id.quantity_text_view);
Button add = (Button) convertView.findViewById(R.id.add);
String pid = productitems.get(position).get(0);
String pname = productitems.get(position).get(1);
String pprice = productitems.get(position).get(2);
String pav = productitems.get(position).get(3);
Integer pqnt;
id.setText(pid);
name.setText(pname);
price.setText(pprice);
av.setText(pav);
plus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//do something
quantity = quantity + 1;
TextView quantityTextView = (TextView) v.findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + quantity);
notifyDataSetChanged();
}
});
minus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//do something
quantity = quantity - 1;
TextView quantityTextView = (TextView) v.findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + quantity);
notifyDataSetChanged();
}
});
add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//do something
quantity = quantity - 1;
TextView quantityTextView = (TextView) v.findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + quantity);
notifyDataSetChanged();
}
});
return convertView;
}
}
日志
FATAL EXCEPTION: main
Process: com.example.stratos.fastsupply, PID: 11074
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.stratos.fastsupply/com.example.stratos.fastsupply.AllProductsActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2429)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1342)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5333)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
at android.app.ListActivity.onContentChanged(ListActivity.java:243)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:344)
at android.app.Activity.setContentView(Activity.java:1948)
at com.example.stratos.fastsupply.AllProductsActivity.onCreate(AllProductsActivity.java:57)
at android.app.Activity.performCreate(Activity.java:5343)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1090)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2331)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2429)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1342)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5333)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
XML
> <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
> android:layout_width="fill_parent"
> android:layout_height="fill_parent"
> android:orientation="vertical"
> android:weightSum="1"
> android:baselineAligned="false">
> <!-- Main ListView
> Always give id value as list(@android:id/list)
> -->
>
> <SearchView
> android:layout_width="match_parent"
> android:layout_height="wrap_content"
> android:layout_weight="0.1">
> </SearchView>
>
> <TextView
> android:id="@+id/textView"
> android:layout_width="match_parent"
> android:layout_height="30sp"
>
> android:text="Product Name Price Qnt"
> android:layout_weight="0.1"/>
>
> <ListView
> android:id="@+id/list"
> android:layout_width="fill_parent"
> android:layout_height="347sp"
> android:layout_weight="0.60" />
>
> <Button
> android:id="@+id/sendOrder"
> android:layout_width="match_parent"
> android:layout_height="50sp"
> android:background="#ffff8800"
> android:fontFamily="sans-serif-smallcaps"
> android:text="Send Order"
> android:textColorLink="@color/colorAccent"
> android:textSize="20sp"
> android:layout_weight="0.2"/>
>
>
> </LinearLayout>
答案 0 :(得分：0)
发生此问题是因为Listview中的ID错误，请将ListView窗口小部件更改为：
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="347sp"
android:layout_weight="0.60" />
答案 1 :(得分：-2)
参考。
public class yourAdapter extends ArrayAdapter<Actors> {
LayoutInflater vi;
ViewHolder holder;
int resource;
private final Activity context;
private final ArrayList<Actors> details;
public WifiAdapter(Activity context, int resource , ArrayList<Actors> details) {
super(context, resource, details);
vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
this.context = context;
this.resource = resource;
this.details = details;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if(v == null){
holder = new ViewHolder();
v = vi.inflate(resource, null);
holder.Type = (TextView) v.findViewById(R.id.type);
.......//your remaining code
v.setTag(holder);
}
else {
holder =(ViewHolder) v.getTag();
}
holder.Name.setText(details.get(position).getType());
..........//ur remaining code
return v;
}
static class ViewHolder {
public TextView Type;
//your remaing code
}
}