方法的onCreate（）未找到

Question

public class MainActivity extends Activity { 

static final String[] FRUITS = new String[] { "Apple", "Avocado", "Banana", 
     "Blueberry", "Coconut", "Durian", "Guava", "Kiwifruit", 
     "Jackfruit", "Mango", "Olive", "Pear", "Sugar-apple" }; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    setListAdapter(new ArrayAdapter<String>(this, 
     R.layout.activity_main, FRUITS)); 
    ListView listView = getListView(); 
    listView.setTextFilterEnabled(true); 

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() 
    { 
     public void onItemClick(AdapterView<?> parent, View view, 
      int position, long id) { 
      // When clicked, show a toast with the TextView text 
      Toast.makeText(getApplicationContext(), 
        ((TextView) view).getText(), Toast.LENGTH_SHORT).show(); 
     } 
    }); 

} 


@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
} 

以下錯誤出現：

公共類MainActivity擴展活動{

既然你：

Gradle: cannot find symbol method 
setListAdapter(android.widget.ArrayAdapter<java.lang.String>) 
Gradle: cannot find symbol method getListView() 

Answer 1

您的代碼開頭正在使用getListView（）您必須擴展ListActivity。嘗試

公共類MainActivity擴展ListActivity {

Answer 2

你應該延長ListActivity而不是Activity。你的問題應該早已消失。根據您的需要

Answer 3

becz您使用getlistView延長listactivity 不活動 （）

Answer 4

試試這個..

ListView listView = (ListView) findViewById(R.id.list); 
     listView.setTextFilterEnabled(true); 
     listView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,FRUITS)); 

     listView.setOnItemClickListener(new AdapterView.OnItemClickListener() 
     { 
      public void onItemClick(AdapterView<?> parent, View view,int position, long id) { 
       // When clicked, show a toast with the TextView text 
       Toast.makeText(getApplicationContext(), 
         ((TextView) view).getText(), Toast.LENGTH_SHORT).show(); 
      } 
     }); 

Answer 5

樣品listactivity代碼，改變它：

文件：RES /layout/list_fruit.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:padding="10dp" 
    android:textSize="20sp" > 
</TextView> 

文件：ListFruitActivity.java

import android.app.ListActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 
import android.widget.TextView; 
import android.widget.Toast; 
import android.widget.AdapterView.OnItemClickListener; 

public class ListFruitActivity extends ListActivity { 

    static final String[] FRUITS = new String[] { "Apple", "Avocado", "Banana", 
      "Blueberry", "Coconut", "Durian", "Guava", "Kiwifruit", 
      "Jackfruit", "Mango", "Olive", "Pear", "Sugar-apple" }; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     // no more this 
     // setContentView(R.layout.list_fruit); 

     setListAdapter(new ArrayAdapter<String>(this, R.layout.list_fruit,FRUITS)); 

     ListView listView = getListView(); 
     listView.setTextFilterEnabled(true); 

     listView.setOnItemClickListener(new OnItemClickListener() { 
      public void onItemClick(AdapterView<?> parent, View view, 
        int position, long id) { 
       // When clicked, show a toast with the TextView text 
       Toast.makeText(getApplicationContext(), 
       ((TextView) view).getText(), Toast.LENGTH_SHORT).show(); 
      } 
     }); 

    } 

} 

Answer 6

你應該延長 ListActivity而不是活動，並在XML列表視圖ID必須是

android:id="@android:id/list" 

Answer 7

1. 擴展ListActivity，而不是隻Activity。

   public class MainActivity extends ListActivity { } 
   

2. 在你R.layout.activity_main使用<ListView android:id="@android:id/list"/>

3. 創建列表的適配器。（以下只是爲了說明一個例子。）

   ArrayAdapter arrayAdapter = new ArrayAdapter(this, // Context. 
         ndroid.R.layout.simple_list_item_1, // Specify the row template to use 
         your_array); // your array having data 
   

4. setListAdapter(arrayAdapter);