@ohos.data.preferences (用户首选项)

用户首选项为应用提供Key-Value键值型的数据处理能力，支持应用持久化轻量级数据，并对其修改和查询。

数据存储形式为键值对，键的类型为字符串型，值的存储数据类型包括数字型、字符型、布尔型以及这3种类型的数组类型。

说明：

本模块首批接口从API version 9开始支持。后续版本的新增接口，采用上角标单独标记接口的起始版本。

导入模块

import data_preferences from '@ohos.data.preferences';

常量

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

data_preferences.getPreferences

getPreferences(context: Context, name: string, callback: AsyncCallback<Preferences>): void

获取Preferences实例，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();
let preferences = null;

try {
    data_preferences.getPreferences(context, 'mystore', function (err, val) {
        if (err) {
	        console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
	        return;
	    }
	    preferences = val;
	    console.info("Succeeded in getting preferences.");
	})
} catch (err) {
    console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';

let preferences = null;

class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try {
            data_preferences.getPreferences(this.context, 'mystore', function (err, val) {
                if (err) {
                    console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
                    return;
                }
                preferences = val;
                console.info("Succeeded in getting preferences.");
            })
        } catch (err) {
            console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

data_preferences.getPreferences

getPreferences(context: Context, name: string): Promise<Preferences>

获取Preferences实例，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();

let preferences = null;
try {
    let promise = data_preferences.getPreferences(context, 'mystore');
    promise.then((object) => {
        preferences = object;
        console.info("Succeeded in getting preferences.");
    }).catch((err) => {
        console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';

let preferences = null;

class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try {
            let promise = data_preferences.getPreferences(this.context, 'mystore');
            promise.then((object) => {
                preferences = object;
                console.info("Succeeded in getting preferences.");
            }).catch((err) => {
                console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
            })
        } catch(err) {
            console.info("Failed to get preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

data_preferences.deletePreferences

deletePreferences(context: Context, name: string, callback: AsyncCallback<void>): void

从内存中移除指定的Preferences实例，使用callback异步回调。

若Preferences实例有对应的持久化文件，则同时删除其持久化文件。

调用该接口后，应用不允许再使用该Preferences实例进行数据操作，否则会出现数据一致性问题。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

错误码：

以下错误码的详细介绍请参见用户首选项错误码。

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();

try {
    data_preferences.deletePreferences(context, 'mystore', function (err) {
        if (err) {
            console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in deleting preferences." );
    })
} catch (err) {
    console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try {
            data_preferences.deletePreferences(this.context, 'mystore', function (err) {
                if (err) {
                    console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
                    return;
                }
                console.info("Succeeded in deleting preferences." );
            })
        } catch (err) {
            console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

data_preferences.deletePreferences

deletePreferences(context: Context, name: string): Promise<void>

从内存中移除指定的Preferences实例，使用Promise异步回调。

若Preferences实例有对应的持久化文件，则同时删除其持久化文件。

调用该接口后，应用不允许再使用该Preferences实例进行数据操作，否则会出现数据一致性问题。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

错误码：

以下错误码的详细介绍请参见用户首选项错误码。

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();

try {
    let promise = data_preferences.deletePreferences(context, 'mystore');
    promise.then(() => {
        console.info("Succeeded in deleting preferences.");
    }).catch((err) => {
        console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try{
            let promise = data_preferences.deletePreferences(this.context, 'mystore');
            promise.then(() => {
                console.info("Succeeded in deleting preferences.");
            }).catch((err) => {
                console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
            })
        } catch(err) {
            console.info("Failed to delete preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

data_preferences.removePreferencesFromCache

removePreferencesFromCache(context: Context, name: string, callback: AsyncCallback<void>): void

从内存中移除指定的Preferences实例，使用callback异步回调。

调用该接口后，应用不允许再使用该Preferences实例进行数据操作，否则会出现数据一致性问题。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();

try {
    data_preferences.removePreferencesFromCache(context, 'mystore', function (err) {
        if (err) {
            console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in removing preferences.");
    })
} catch (err) {
    console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';
class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try {
            data_preferences.removePreferencesFromCache(this.context, 'mystore', function (err) {
                if (err) {
                    console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
                    return;
                }
                console.info("Succeeded in removing preferences.");
            })
        } catch (err) {
            console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

data_preferences.removePreferencesFromCache

removePreferencesFromCache(context: Context, name: string): Promise<void>

从内存中移除指定的Preferences实例，使用Promise异步回调。

调用该接口后，应用不允许再使用该Preferences实例进行数据操作，否则会出现数据一致性问题。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

FA模型示例：

// 获取context
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();

try {
    let promise = data_preferences.removePreferencesFromCache(context, 'mystore');
	promise.then(() => {
    	console.info("Succeeded in removing preferences.");
    }).catch((err) => {
        console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
}

Stage模型示例：

import UIAbility from '@ohos.app.ability.UIAbility';

class EntryAbility extends UIAbility {
    onWindowStageCreate(windowStage) {
        try {
            let promise = data_preferences.removePreferencesFromCache(this.context, 'mystore');
            promise.then(() => {
                console.info("Succeeded in removing preferences.");
            }).catch((err) => {
                console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
            })
        } catch(err) {
            console.info("Failed to remove preferences. code =" + err.code + ", message =" + err.message);
        }
    }
}

Preferences

存储实例，提供获取和修改存储数据的接口。

下列接口都需先使用data_preferences.getPreferences获取到Preferences实例，再通过此实例调用对应接口。

get

get(key: string, defValue: ValueType, callback: AsyncCallback<ValueType>): void

获取键对应的值，如果值为null或者非默认值类型，返回默认数据defValue，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.get('startup', 'default', function (err, val) {
        if (err) {
            console.info("Failed to get value of 'startup'. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in getting value of 'startup'. val： " + val);
    })
} catch (err) {
    console.info("Failed to get value of 'startup'. code =" + err.code + ", message =" + err.message);
}

get

get(key: string, defValue: ValueType): Promise<ValueType>

获取键对应的值，如果值为null或者非默认值类型，返回默认数据defValue，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

try {
    let promise = preferences.get('startup', 'default');
    promise.then((data) => {
        console.info("Succeeded in getting value of 'startup'. Data: " + data);
    }).catch((err) => {
        console.info("Failed to get value of 'startup'. code =" + err.code + ", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to get value of 'startup'. code =" + err.code + ", message =" + err.message);
}

getAll

getAll(callback: AsyncCallback<Object>): void;

获取含有所有键值的Object对象。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.getAll(function (err, value) {
        if (err) {
            console.info("Failed to get all key-values. code =" + err.code + ", message =" + err.message);
            return;
        }
    let allKeys = Object.keys(value);
    console.info("getAll keys = " + allKeys);
    console.info("getAll object = " + JSON.stringify(value));
    })
} catch (err) {
    console.info("Failed to get all key-values. code =" + err.code + ", message =" + err.message);
}

getAll

getAll(): Promise<Object>

获取含有所有键值的Object对象。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

返回值：

示例：

try {
    let promise = preferences.getAll();
    promise.then((value) => {
        let allKeys = Object.keys(value);
        console.info('getAll keys = ' + allKeys);
        console.info("getAll object = " + JSON.stringify(value));
    }).catch((err) => {
        console.info("Failed to get all key-values. code =" + err.code + ", message =" + err.message);
    })
} catch (err) {
    console.info("Failed to get all key-values. code =" + err.code + ", message =" + err.message);
}

put

put(key: string, value: ValueType, callback: AsyncCallback<void>): void

将数据写入Preferences实例，可通过flush将Preferences实例持久化，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.put('startup', 'auto', function (err) {
        if (err) {
            console.info("Failed to put value of 'startup'. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in putting value of 'startup'.");
    })
} catch (err) {
    console.info("Failed to put value of 'startup'. code =" + err.code + ", message =" + err.message);
}

put

put(key: string, value: ValueType): Promise<void>

将数据写入Preferences实例，可通过flush将Preferences实例持久化，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

try {
    let promise = preferences.put('startup', 'auto');
    promise.then(() => {
        console.info("Succeeded in putting value of 'startup'.");
    }).catch((err) => {
        console.info("Failed to put value of 'startup'. code =" + err.code +", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to put value of 'startup'. code =" + err.code +", message =" + err.message);
}

has

has(key: string, callback: AsyncCallback<boolean>): void

检查Preferences实例是否包含名为给定Key的存储键值对，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.has('startup', function (err, val) {
        if (err) {
            console.info("Failed to check the key 'startup'. code =" + err.code + ", message =" + err.message);
            return;
        }
        if (val) {
            console.info("The key 'startup' is contained.");
        } else {
            console.info("The key 'startup' dose not contain.");
        }
  })
} catch (err) {
    console.info("Failed to check the key 'startup'. code =" + err.code + ", message =" + err.message);
}

has

has(key: string): Promise<boolean>

检查Preferences实例是否包含名为给定Key的存储键值对，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

try {
    let promise = preferences.has('startup');
    promise.then((val) => {
        if (val) {
            console.info("The key 'startup' is contained.");
        } else {
            console.info("The key 'startup' dose not contain.");
        }
    }).catch((err) => {
        console.info("Failed to check the key 'startup'. code =" + err.code + ", message =" + err.message);
  })
} catch(err) {
    console.info("Failed to check the key 'startup'. code =" + err.code + ", message =" + err.message);
}

delete

delete(key: string, callback: AsyncCallback<void>): void

从Preferences实例中删除名为给定Key的存储键值对，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.delete('startup', function (err) {
        if (err) {
            console.info("Failed to delete the key 'startup'. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in deleting the key 'startup'.");
    })
} catch (err) {
    console.info("Failed to delete the key 'startup'. code =" + err.code + ", message =" + err.message);
}

delete

delete(key: string): Promise<void>

从Preferences实例中删除名为给定Key的存储键值对，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

返回值：

示例：

try {
    let promise = preferences.delete('startup');
	promise.then(() => {
        console.info("Succeeded in deleting the key 'startup'.");
    }).catch((err) => {
        console.info("Failed to delete the key 'startup'. code =" + err.code +", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to delete the key 'startup'. code =" + err.code +", message =" + err.message);
}

flush

flush(callback: AsyncCallback<void>): void

将当前Preferences实例的数据异步存储到用户首选项的持久化文件中，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    preferences.flush(function (err) {
        if (err) {
            console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in flushing.");
    })
} catch (err) {
    console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
}

flush

flush(): Promise<void>

将当前Preferences实例的数据异步存储到用户首选项的持久化文件中，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

返回值：

示例：

try {
    let promise = preferences.flush();
    promise.then(() => {
        console.info("Succeeded in flushing.");
    }).catch((err) => {
        console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
    })
} catch (err) {
    console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
}

clear

clear(callback: AsyncCallback<void>): void

清除此Preferences实例中的所有存储，使用callback异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
	preferences.clear(function (err) {
        if (err) {
            console.info("Failed to clear. code =" + err.code + ", message =" + err.message);
            return;
        }
        console.info("Succeeded in clearing.");
    })
} catch (err) {
    console.info("Failed to clear. code =" + err.code + ", message =" + err.message);
}

clear

clear(): Promise<void>

清除此Preferences实例中的所有存储，使用Promise异步回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

返回值：

示例：

try {
    let promise = preferences.clear();
	promise.then(() => {
    	console.info("Succeeded in clearing.");
    }).catch((err) => {
        console.info("Failed to clear. code =" + err.code + ", message =" + err.message);
    })
} catch(err) {
    console.info("Failed to clear. code =" + err.code + ", message =" + err.message);
}

on('change')

on(type: 'change', callback: Callback<{ key : string }>): void

订阅数据变更，订阅的Key的值发生变更后，在执行flush方法后，触发callback回调。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
	data_preferences.getPreferences(this.context, 'mystore', function (err, preferences) {
		if (err) {
			console.info("Failed to get preferences.");
			return;
		}
		let observer = function (key) {
			console.info("The key " + key + " changed.");
		}
		preferences.on('change', observer);
		preferences.put('startup', 'manual', function (err) {
			if (err) {
				console.info("Failed to put the value of 'startup'. Cause: " + err);
				return;
			}
			console.info("Succeeded in putting the value of 'startup'.");

			preferences.flush(function (err) {
				if (err) {
					console.info("Failed to flush. Cause: " + err);
					return;
				}
				console.info("Succeeded in flushing.");
			})
		})
	})
} catch (err) {
	console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
}

off('change')

off(type: 'change', callback?: Callback<{ key : string }>): void

取消订阅数据变更。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core

参数：

示例：

try {
    data_preferences.getPreferences(this.context, 'mystore', function (err, preferences) {
        if (err) {
            console.info("Failed to get preferences.");
            return;
        }
        let observer = function (key) {
            console.info("The key " + key + " changed.");
        }
        preferences.on('change', observer);
        preferences.put('startup', 'auto', function (err) {
            if (err) {
                console.info("Failed to put the value of 'startup'. Cause: " + err);
                return;
            }
            console.info("Succeeded in putting the value of 'startup'.");

            preferences.flush(function (err) {
                if (err) {
                    console.info("Failed to flush. Cause: " + err);
                    return;
                }
                console.info("Succeeded in flushing.");
            })
            preferences.off('change', observer);
        })
    })
} catch (err) {
    console.info("Failed to flush. code =" + err.code + ", message =" + err.message);
}

ValueType

用于表示允许的数据字段类型。

系统能力： SystemCapability.DistributedDataManager.Preferences.Core