所以我有两个带有一些文本的EditText字段，我想保存并在以后加载。这样做的最佳方法是什么？它必须保存在手机上，而不是保存在在线互联网数据库（如Firebase）上。
我想到的解决方案是：
1。将其保存在单个文本文件中，并删除.txt扩展名。
a. Here I will use keywords which my code can read like <START OF DATA(x)>
where x is the id of the data saved.(
b. This obviously will take a long time to implement but it will make. But
will be a lot neater than solution #2.
2。将每个结果保存到单独的文本文件中，并删除.txt扩展名。 一个。在这里，我将结果保存到相应的文本文件中（例如：res0001）。
b. I will use a third party file explorer to load the text contained in the
text file.
c. This is easier to implement than solution #1.
关于如何最好地处理我的问题的任何其他建议？也许一个API？
答案 0 :(得分：1)
您可以将值保存在“首选项”中。下面的课程将让您轻松保存数据并从首选项
中进行检索public class SessionManager {
private SharedPreferences pref;
private static SessionManager sessionManager;
public static SessionManager getInstance(Context context) {
if(sessionManager == null){
sessionManager = new SessionManager(context);
}
return sessionManager;
}
public SessionManager(Context context) {
String PREF_NAME = context.getResources().getString(R.string.app_name);
this.pref = context.getSharedPreferences(PREF_NAME,Context.MODE_PRIVATE);
}
/**
* Getting value for key from shared Preferences
*
* @param key key for which we need to get Value
* @param defaultValue default value to be returned if key is not exits
* @return It will return value of key if exist and defaultValue otherwise
*/
public String getValueFromKey(String key, String defaultValue) {
if (pref.containsKey(key)) {
return pref.getString(key, defaultValue);
} else {
return defaultValue;
}
}
/**
* Setting value for key from shared Preferences
*
* @param key key for which we need to get Value
* @param value value for the key
*/
public void setValueFromKey(String key, String value) {
pref.putString(key, value).apply();
}
/**
* Setting value for key from shared Preferences
*
* @param key key for which we need to get Value
* @param value value for the key
*/
public void setFlagFromKey(String key, boolean value) {
pref.putBoolean(key, value).apply();
}
/**
* To get Flag from sharedPreferences
*
* @param key key of flag to get
* @return flag value for key if exist. false if not key not exist.
*/
public boolean getFlagFromKey(String key) {
return pref.containsKey(key) && pref.getBoolean(key, false);
}
}
答案 1 :(得分：0)
Lex_F您可以使用SharedPreferences，但如果用户从设置中清除应用程序的应用程序数据或缓存，那么您的SharedPreferences会提供默认值而不是实际保存的值。对于永久存储，您可以使用SQLite数据库但需要SQLite更多样板代码。我认为你应该尝试使用非常简单易用的领域数据库。这取决于你应该使用哪个数据库。但我会给出真实数据库的例子。
public class UserInformation extends RealmObject {
private String name;
@PrimaryKey //define the phone number as a primary key
private String phone;
private String address;
private String gmail;
public UserInformation() {
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPhone() {
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getGmail() {
return gmail;
}
public void setGmail(String gmail) {
this.gmail = gmail;
}
}
现在进行任何活动
Realm realm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Realm.init(this);
realm = Realm.getDefaultInstance();
//insert the data into the realm database
insert.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
realm.executeTransactionAsync(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
//second argument represent the primary key
UserInformation information = realm.createObject(UserInformation.class, phone.getText().toString());
information.setName(name.getText().toString());
information.setGmail(email.getText().toString());
information.setAddress(address.getText().toString());
realm.copyToRealm(information);
}
}, new Realm.Transaction.OnSuccess() {
@Override
public void onSuccess() {
Toast.makeText(MainActivity.this, "Successfully inserted data..", Toast.LENGTH_SHORT).show();
}
}, new Realm.Transaction.OnError() {
@Override
public void onError(Throwable error) {
Toast.makeText(MainActivity.this, "Something wrong please try again later..", Toast.LENGTH_SHORT).show();
}
});
}
});
update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
realm.executeTransactionAsync(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
RealmResults<UserInformation> query = realm.where(UserInformation.class).equalTo("phone", phone.getText().toString()).findAll();
//if query not gives any result then query.size() return give 0 value
if (query.size() == 0) {
ToastLogUtil.toastmessage(MainActivity.this, "You entered wrong information or might be your entered phone no not matches existing information");
} else {
for (UserInformation info : query) {
info.setName(name.getText().toString());
// info.setPhone(phone.getText().toString());
info.setGmail(email.getText().toString());
info.setAddress(address.getText().toString());
realm.copyToRealm(info);
}
ToastLogUtil.toastmessage(MainActivity.this, "Successfully updated data");
}
}
}, new Realm.Transaction.OnSuccess() {
@Override
public void onSuccess() {
ToastLogUtil.toastmessage(MainActivity.this, "Your Information Updated Successfully..");
}
}, new Realm.Transaction.OnError() {
@Override
public void onError(Throwable error) {
clearData();
ToastLogUtil.toastmessage(MainActivity.this, "Your Information not Updated something wrong...");
ToastLogUtil.errorlog(error.toString());
}
});
}
});
retrieve.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (TextUtils.isEmpty(name.getText().toString()) && TextUtils.isEmpty(phone.getText().toString()) && TextUtils.isEmpty(email.getText().toString()) && TextUtils.isEmpty(address.getText().toString())) {
//at this you can retrieve all information
RealmResults<UserInformation> query = realm.where(UserInformation.class).findAllAsync();
for (UserInformation info : query) {
text.append(info.getName() + "\n");
text.append(info.getPhone() + "\n");
text.append(info.getGmail() + "\n");
text.append(info.getAddress() + "\n");
}
ToastLogUtil.toastmessage(MainActivity.this,"retrieve all data successfully...");
} else {
//at this query you can retrieve specific user which have a same phone which you enter in .equalTO() method
RealmResults<UserInformation> query = realm.where(UserInformation.class).equalTo("phone", phone.getText().toString()).findAll();
for (UserInformation info : query) {
text.append(info.getName() + "\n");
text.append(info.getPhone() + "\n");
text.append(info.getGmail() + "\n");
text.append(info.getAddress() + "\n");
ToastLogUtil.toastmessage(MainActivity.this,"Retrieve "+info.getPhone()+ " data successfully...");
}
}
}
});
delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (TextUtils.isEmpty(phone.getText().toString())) {
ToastLogUtil.toastmessage(MainActivity.this, "Please mention the phone number you want to delete");
} else {
RealmResults<UserInformation> query = realm.where(UserInformation.class).equalTo("phone", phone.getText().toString()).findAllAsync();
if (query.size() == 0) {
ToastLogUtil.toastmessage(MainActivity.this,"Your phone no not matches in our database phone no..");
} else {
realm.beginTransaction();
query.deleteAllFromRealm();
realm.commitTransaction();
ToastLogUtil.toastmessage(MainActivity.this, "Delete data successfully...");
}
}
}
});
}
谢谢： - ）
不要忘记添加领域依赖项
//将类路径依赖项添加到项目级build.gradle文件。
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "io.realm:realm-gradle-plugin:4.3.3"
}
}
//将realm-android插件应用到应用程序级build.gradle文件的顶部。
apply plugin: 'realm-android'