嘗試開發Android應用程序時獲取java.lang.ClassCastException

Question

我有這個異常“ java.lang.ClassCastException：android.app.Application無法轉換為com.utility.TablePlussAndroid”，我不明白為什么...非常感謝您的幫助

package com.tableplustablet;
private com.utility.TablePlusAndroid session;

public class LoginActivity extends Activity {

    // ...

    // get session from Application                        
    session =  (TablePlusAndroid) this.getApplication(); // <--EXCEPTION
    session.setUserKey(userKey);
} 

// -------------------------------------------------------------

package com.utility;
import android.app.Application;

 //Save User Data in  application's context
 public class TablePlusAndroid extends Application{
private Long userKey;
private String userName;
private Long currentTableKey;  

    public Long getCurrentTableKey() {
        return currentTableKey;
}

    public void setCurrentTableKey(Long currentTableKey) {
        this.currentTableKey = currentTableKey;
    }
    public Long getUserKey(){ return userKey;}
    public void setUserKey(Long key){ userKey=key;}
    public String getUserName() { return userName; }
    public void setUserName(String userName) { this.userName = userName; }  
}

Answer 1

您需要在AndroidManifest.xml文件中使用應用程序類。

它看起來應該像這樣：

<application android:name="application.package.and.class">
    <activity .... />
</application>