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【java】按位存储：使用int存储boolean数组 | iTimeTraveler

 4 years ago
source link: https://itimetraveler.github.io/2016/06/02/%E3%80%90Java%E3%80%91%E6%8C%89%E4%BD%8D%E5%AD%98%E5%82%A8%EF%BC%9A%E4%BD%BF%E7%94%A8int%E5%AD%98%E5%82%A8boolean%E6%95%B0%E7%BB%84/
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【Java】按位存储：使用int存储boolean数组

有一种场景，比如App设置页中会有一组开关选项，这个时候保存这些开关的状态，如果每个按钮都对应一个boolean值的话，太大材小用显得鸡肋，频繁读取SharedPreferences 存取效率自然快不过一次读取。

首先，敲定每个boolean值存储的位置

private int mBroadcastCustomValue = 0;   //用来存储的int值
public static final int BROADCAST_TYPE_CUSTOM_BASE = 1;
public static final int BROADCAST_TYPE_CUSTOM_TRAFFIC = 1 << 1;
public static final int BROADCAST_TYPE_CUSTOM_CAMERA = 1 << 2;
public static final int BROADCAST_TYPE_CUSTOM_SAFE = 1 << 3;

一、添加Add

private void addLevel(int level){
	mBroadcastCustomValue |= level;    //add
}

//调用方式如下
addLevel(BROADCAST_TYPE_CUSTOM_BASE);

二、删除Delete

private void deleteLevel(int level){
	mBroadcastCustomValue ^= mBroadcastCustomValue & level;	    //delete
}

//调用方式如下
deleteLevel(BROADCAST_TYPE_CUSTOM_BASE);

三、读取Read

/**
 * 从value中读取level的设置值，level即是某个boolean值的位置
 */
private boolean isLevelAccess(int value, int level){
	if((value & level) == level){
		return true;
	}
	return false;
}

//调用方式如下
boolean a = isLevelAccess(mBroadcastCustomValue, BROADCAST_TYPE_CUSTOM_BASE);

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