使用全局变量 [英] Using Global Variables

问题描述

我知道这个问题已经被问了一百万次，因为我已经做了一些调查，发现许多线程这一点。我曾尝试在这些线程使用的答案，但我有一个有点麻烦。

I know this question has been asked a million times because I have done some research and have found many threads on this. I have tried to use the answers in those threads but I am having a bit of trouble.

我期待以设置，我可以在我的所有活动都使用了一些变数。

I am looking to set a few variables that I can use across all of my activities.

我创建了一个GlobalVariables.java类看起来像下面（的价值存在只是为了测试目的截至目前）：

I created a GlobalVariables.java class which looks like the following (the value in there is just for testing purposes as of now):

import android.app.Application;

public class GlobalVariables extends Application {

int holeAmount;

public int getHoles(){
    return holeAmount;
  }
  public void setHoles(String s){
    holeAmount = 30;
  }

}

在我的主要活动，一切正在发生的事情，我有以下：

in my main activity where everything is happening I have the following:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    GlobalVariables global = ((GlobalVariables)getApplicationContext());
    int totalHoles = global.getHoles();

和对GlobalVariables全球= ...行，我收到以下错误：

and on the "GlobalVariables global = ..." line I am getting the following error:

Multiple markers at this line
- GlobalVariables cannot be resolved 
 to a type
- GlobalVariables cannot be resolved 
 to a type

我想在这里按照说明进行操作，但显然，我错误地做一些事情。 > 安卓：？如何声明全局变量

任何帮助将大大AP preciated！

Any help would be greatly appreciated!

谢谢！

第二次尝试：

EasyPar.java （错误@ EasyParHelperActivity）

EasyPar.java (Errors @ EasyParHelperActivity)

package com.movi.easypar;

import java.text.DateFormat;
import java.util.Date;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.Button;
import android.widget.ScrollView;
import android.widget.TextView;
import android.widget.Toast;

public class EasyPar extends Activity implements OnClickListener {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

(initialize all my buttons and textviews)
}

public void someMethod() {
    EasyParHelperActivity.helper.setHoles(30);
    int holes = EasyParHelperActivity.helper.getHoles();
}

(the rest of my button functions, etc.)

EasyParHelperActivity （无错误）

package com.movi.easypar;

import android.app.Application;

public class EasyParHelperActivity extends Application {

public static EasyParHelper helper = new EasyParHelper();

}

EasyParHelper.java （无错误）

package com.movi.easypar;

public class EasyParHelper {

private int holeAmount = 0;

public int getHoles() {
    return holeAmount;
}

public void setHoles(int holes) {
    holeAmount = holes;
}
}

我要的是用户能够点击的第一个屏幕上的按钮，18或9为，并为应用程序能够使用该值其他时间全不管它。所以，我需要将其设置为1的屏幕，并在屏幕2我需要检索该值。

All i want is for the user to be able to click a button "18" or "9" on the first screen, and for the application to be able to use that value other times throughout whatever it does. So I need to set it in screen 1, and in screen 2 i need to retrieve that value.

推荐答案

创建一个助手类，如下所示...

Create a 'helper' class as follows...

package com.my.application

public class MyAppHelper {

    private int holeAmount = 0;

    public int getHoles() {
        return holeAmount;
    }

    public void setHoles(int holes) {
        holeAmount = holes;
    }
}

然后为你的应用程序类执行下列操作...

Then for your Application class do the following...

package com.my.application

public class MyApplication extends Application {

    public static MyAppHelper helper = new MyAppHelper();

}

要访问你可以简单地调用助手的get / set方法...

To get access to the get/set methods in the helper you can simply call...

package com.my.application

public class MyActivity extends Activity {

    // Normal onCreate(...) etc here

    public void someMethod() {
        MyApplication.helper.setHoles(30);
        int holes = MyApplication.helper.getHoles();
    }
}

这篇关于使用全局变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！