創建全球課堂。錯誤：android.app.application不能轉換爲com

Question

我試圖創建一個全局類。我想爲我的所有活動都有一個全局變量。

我的類：

package com.example.app; 

import java.io.BufferedReader; 
import java.io.File; 
import java.io.FileReader; 
import java.io.FileWriter; 
import java.io.IOException; 

import android.app.Application; 

public class Records extends Application{ 

private int N_livelli=30; 
private int[] record = new int[N_livelli]; 
private String path = getApplicationContext().getFilesDir().getPath() + "/Records.txt"; 

public void LetturaFile() 
{ 
    File f = new File(path); 
    if(f.exists()) 
    { 
     try 
     { 
      FileReader fileLeggi = new FileReader(path); 
      BufferedReader lettore = new BufferedReader(fileLeggi); 
      String rigaLetta; 
      int n=0; 
      while((rigaLetta=lettore.readLine())!=null) 
      { 
       record[n]=Integer.valueOf(rigaLetta); 
       n++; 
      } 
      lettore.close(); 
      fileLeggi.close(); 
     } 
     catch (IOException e) 
     { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 
    else 
    { 
     try 
     { 
      for(int i=0;i<N_livelli;i++) record[i]=0; 
      f.createNewFile(); 
      FileWriter fileScrivi = new FileWriter(path); 
      fileScrivi.write(""); 
      for(int i=0;i<N_livelli;i++) fileScrivi.append(record[i]+"\n"); 
      fileScrivi.close(); 
     } 
     catch (IOException e) 
     { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 
} 

public int getRecord(int livello) 
{ 
    return record[livello-1]; 
} 
} 

我在MainActivity中的OnCreate代碼：

[...] 
Records records = (Records) getApplicationContext(); 
records.LetturaFile(); 
[..] 

我的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="com.example.app" 
android:versionCode="3" 
android:versionName="1.0" > 

<uses-sdk 
    android:minSdkVersion="9" 
    android:targetSdkVersion="21" /> 

<application 
    android:allowBackup="true" 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:theme="@style/AppTheme" > 

    <activity 
     android:name=".MainActivity" 
     [...] 
    </activity> 
    <activity 
     android:name=".SecondActivity" 
     [...] 
    </activity> 
</application> 
<application 
    android:name=".Records"> 
</application> 
</manifest> 

Eclipse的錯誤：android.app.application不能cast to com.example.app.Records

請幫幫我。謝謝。

Answer 1

你必須指定在應用程序標籤類的FUL路徑，而不是通過增加與任何東西的另一個應用程序標籤..

<application 
android:allowBackup="true" 
android:icon="@drawable/ic_launcher" 
android:label="@string/app_name" 
android:theme="@style/AppTheme" 
android:name="com.example.app.Records" > 
...