Question

private static final String KEY_HOROSCOPE = "HOROSCOPE";
private String mHoroscope;

鉴于上面的代码，如何持久保存mHoroscope的值？保存时，如何加载mHoroscope的持久存储值？

Answer 1

您可以使用文件来保存变量的值

从文件中读取：

File f = new File(Address);
FileReader r = new FileReader(f);
BufferedReader b = new BufferedReader(r);
String out = "";
String k="";
while( (out=b.readLine()) != null) {
    k+=out;
}
b.close();

所以字符串k就是答案

写入文件：

File file = new File(Address);
FileWriter fw = new FileWriter(file, true);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(YourString);  
bw.close();

Answer 2

您可以使用SharedPreferences保存值。

private SharedPreferences mPreferences = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // initialize the SharedPreferences, 'this' is a context
    mPreferences = PreferenceManager.getDefaultSharedPreferences(this);
}

// get the value for key (suppose the value type is boolean)
private boolean getBoolean(String key, boolean defValue) {
    return mPreferences.getBoolean(key, defValue);
}

// save the value for key (suppose the value type is boolean)
private void putBoolean(String key, boolean value) {
    mPreferences.edit().putBoolean(key, value).apply();
}

Answer 3

关闭应用时，将SharedPreference用于持久数据创建一个全局变量

SharedPreferences mSharedPreference;

初始化onCreate

mSharedPreferences = getApplicationContext().getSharedPreferences("MyPref", 0);

存储值：

Editor e = mSharedPreferences.edit();
e.putString(KEY_HOROSCOPE, value);
e.commit();

要追溯：

String horoscope = mSharedPreferences.getString(KEY_HOROSCOPE, "");

如果您只想在关闭应用时清除它，请使用Bundle。

在Java中保存值和加载值

3 个答案: