Android全局变量

如何在应用程序的生命周期中创建全局变量keep keep values而不管哪个活动正在运行..


你可以扩展基类android.app.Application类并添加成员变量,如下所示:

public class MyApplication extends Application {

    private String someVariable;

    public String getSomeVariable() {
        return someVariable;
    }

    public void setSomeVariable(String someVariable) {
        this.someVariable = someVariable;
    }
}

在您的android清单中,您必须声明实现android.app.Application的类(将android:name=".MyApplication"属性添加到现有应用程序标记中):

<application 
  android:name=".MyApplication" 
  android:icon="@drawable/icon" 
  android:label="@string/app_name">

然后在你的活动中,你可以像这样获取和设置变量:

// set
((MyApplication) this.getApplication()).setSomeVariable("foo");

// get
String s = ((MyApplication) this.getApplication()).getSomeVariable();

你可以像这样使用一个Singleton Pattern

package com.ramps;

public class MyProperties {
private static MyProperties mInstance= null;

public int someValueIWantToKeep;

protected MyProperties(){}

public static synchronized MyProperties getInstance() {
        if(null == mInstance){
            mInstance = new MyProperties();
        }
        return mInstance;
    }
}

在你的应用程序中,你可以用这种方式访问​​你的单身人士:

MyProperties.getInstance().someValueIWantToKeep

这个全局变量适用于我的项目:

public class Global {
    public static int ivar1, ivar2;
    public static String svar1, svar2;
    public static int[] myarray1 = new int[10];
}


//  How to use other or many activity
Global.ivar1 = 10;

int i = Global.ivar1;
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