搜索列表视图正在检索错误..我不知道为什么

Question

下面的代码运行良好。 老实说，我什至不认为我改变了什么。 它停止工作。 我有一个自定义列表视图，错误是在该自定义列表视图中搜索。 我创建了一个自定义适配器等。

// Products Activity:
listView = (ListView) findViewById(R.id.product_listview);
inputSearch = (EditText) findViewById(R.id.inputSearch);

adapter = new itemAdapter(this,R.layout.row, display_products);
listView.setAdapter(adapter);

/**
 * Enabling Search Filter
 * */
inputSearch.addTextChangedListener(new TextWatcher() {

    @Override
    public void afterTextChanged(Editable arg0) {
        // TODO Auto-generated method stub
        String text = inputSearch.getText().toString().toLowerCase(Locale.getDefault());
        adapter.filter(text);
    }

    @Override
    public void beforeTextChanged(CharSequence arg0, int arg1,
            int arg2, int arg3) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onTextChanged(CharSequence arg0, int arg1, int arg2,
            int arg3) {
        // TODO Auto-generated method stub
    }
});

这是自定义适配器上的过滤器（我没有放置 getView 方法，因为它正在工作......但如果你需要让我知道。）：

public class itemAdapter extends ArrayAdapter<oc_product_display> {

    private final Context context;
    private final List<oc_product_display> lista;
    private ArrayList<oc_product_display> arraylist;
    private final int rowResourceId;

    public itemAdapter(Context context, int textViewResourceId, List<oc_product_display> objects) {

        super(context, textViewResourceId, objects);
        this.context = context;
        this.lista = objects;
        this.rowResourceId = textViewResourceId;
        this.arraylist = new ArrayList<oc_product_display>();
        this.arraylist.addAll(lista);
    }

    public void filter(String charText) {
        charText = charText.toLowerCase(Locale.getDefault());
        lista.clear();
        if (charText.length() == 0) {
            lista.addAll(arraylist);
        } else {
            for (oc_product_display wp : arraylist) {
                if (wp.get_name().toLowerCase(Locale.getDefault())
                        .contains(charText)) {
                    lista.add(wp);
                }
            }
        }
        notifyDataSetChanged();
    }
}

日志猫

  And this is the error: 10-04 06:29:08.576: E/AndroidRuntime(10284):
 FATAL EXCEPTION: main 10-04 06:29:08.576: E/AndroidRuntime(10284):
 java.lang.RuntimeException: Unable to start activity
 ComponentInfo{com.example.myExample/com.example.myExample.ProductsActivity}:
 java.lang.NullPointerException 10-04 06:29:08.576:
 E/AndroidRuntime(10284):   at
 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 android.app.ActivityThread.access$600(ActivityThread.java:141) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 android.os.Handler.dispatchMessage(Handler.java:99) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 android.os.Looper.loop(Looper.java:137) 10-04 06:29:08.576:
 E/AndroidRuntime(10284):   at
 android.app.ActivityThread.main(ActivityThread.java:5103) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 java.lang.reflect.Method.invokeNative(Native Method) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 java.lang.reflect.Method.invoke(Method.java:525) 10-04 06:29:08.576:
 E/AndroidRuntime(10284):   at
 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 dalvik.system.NativeStart.main(Native Method) 10-04 06:29:08.576:
 E/AndroidRuntime(10284): Caused by: java.lang.NullPointerException
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 com.example.myExample.ProductsActivity.onCreate(ProductsActivity.java:46)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 android.app.Activity.performCreate(Activity.java:5133) 10-04
 06:29:08.576: E/AndroidRuntime(10284):     at
 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   at
 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
 10-04 06:29:08.576: E/AndroidRuntime(10284):   ... 11 more

正如您在网上看到的那样：10-04 06:29:08.576: E/AndroidRuntime(10284): at com.example.myExample.ProductsActivity.onCreate(ProductsActivity.java:46)

这是：

inputSearch.addTextChangedListener(new TextWatcher() {

如果我删除搜索选项，则会显示产品并且不会出现任何错误。 谢谢。

Answer 1

Logcat 说明了一切：

Caused by: java.lang.NullPointerException at com.example.myExample.ProductsActivity.onCreate(ProductsActivity.java:46)

检查此行是否为空。

如果该行是您在问题上声明的那一行……那么您的“inputSearch”可能为空。 确保您在正确的布局上找到此视图。