我有三个活动A, B和C,其中A和B是表单,并在数据库(SQLite)中填充和保存表单数据后。我使用意图从A到B,然后从B到C,我想要的是,每次我打开我的应用程序时,我想要C作为我的主屏幕,而不再是A和B。
我想共享偏好可以解决这个问题,但我找不到一个好的例子来给我一个起点。
我有三个活动A, B和C,其中A和B是表单,并在数据库(SQLite)中填充和保存表单数据后。我使用意图从A到B,然后从B到C,我想要的是,每次我打开我的应用程序时,我想要C作为我的主屏幕,而不再是A和B。
我想共享偏好可以解决这个问题,但我找不到一个好的例子来给我一个起点。
当前回答
Initialise here..
SharedPreferences msharedpref = getSharedPreferences("msh",
MODE_PRIVATE);
Editor editor = msharedpref.edit();
store data...
editor.putString("id",uida); //uida is your string to be stored
editor.commit();
finish();
fetch...
SharedPreferences prefs = this.getSharedPreferences("msh", Context.MODE_PRIVATE);
uida = prefs.getString("id", "");
其他回答
在“偏好”中设置值:
// MY_PREFS_NAME - a static String variable like:
//public static final String MY_PREFS_NAME = "MyPrefsFile";
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
editor.putString("name", "Elena");
editor.putInt("idName", 12);
editor.apply();
从首选项检索数据:
SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE);
String name = prefs.getString("name", "No name defined");//"No name defined" is the default value.
int idName = prefs.getInt("idName", 0); //0 is the default value.
更多信息:
使用共享首选项
共同的喜好
如何初始化?
// 0 - for private mode`
SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0);
Editor editor = pref.edit();
如何在共享偏好中存储数据?
editor.putString("key_name", "string value"); // Storing string
OR
editor.putInt("key_name", "int value"); //Storing integer
别忘了申请:
editor.apply();
如何从共享首选项检索数据?
pref.getString("key_name", null); // getting String
pref.getInt("key_name", 0); // getting Integer
希望这对你有帮助:)
我只是发现上面所有的例子都太混乱了,所以我自己写了一个。如果您知道自己在做什么,那么代码片段是很好的,但是像我这样不知道的人呢?
想要一个剪切-粘贴的解决方案?好了,就是这里!
创建一个新的java文件并将其称为Keystore。然后粘贴以下代码:
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.util.Log;
public class Keystore { //Did you remember to vote up my example?
private static Keystore store;
private SharedPreferences SP;
private static String filename="Keys";
private Keystore(Context context) {
SP = context.getApplicationContext().getSharedPreferences(filename,0);
}
public static Keystore getInstance(Context context) {
if (store == null) {
Log.v("Keystore","NEW STORE");
store = new Keystore(context);
}
return store;
}
public void put(String key, String value) {//Log.v("Keystore","PUT "+key+" "+value);
Editor editor = SP.edit();
editor.putString(key, value);
editor.commit(); // Stop everything and do an immediate save!
// editor.apply();//Keep going and save when you are not busy - Available only in APIs 9 and above. This is the preferred way of saving.
}
public String get(String key) {//Log.v("Keystore","GET from "+key);
return SP.getString(key, null);
}
public int getInt(String key) {//Log.v("Keystore","GET INT from "+key);
return SP.getInt(key, 0);
}
public void putInt(String key, int num) {//Log.v("Keystore","PUT INT "+key+" "+String.valueOf(num));
Editor editor = SP.edit();
editor.putInt(key, num);
editor.commit();
}
public void clear(){ // Delete all shared preferences
Editor editor = SP.edit();
editor.clear();
editor.commit();
}
public void remove(){ // Delete only the shared preference that you want
Editor editor = SP.edit();
editor.remove(filename);
editor.commit();
}
}
现在保存那个文件,忘了它吧。你受够了。现在回到你的活动,像这样使用它:
public class YourClass extends Activity{
private Keystore store;//Holds our key pairs
public YourSub(Context context){
store = Keystore.getInstance(context);//Creates or Gets our key pairs. You MUST have access to current context!
int= store.getInt("key name to get int value");
string = store.get("key name to get string value");
store.putInt("key name to store int value",int_var);
store.put("key name to store string value",string_var);
}
}
Initialise here..
SharedPreferences msharedpref = getSharedPreferences("msh",
MODE_PRIVATE);
Editor editor = msharedpref.edit();
store data...
editor.putString("id",uida); //uida is your string to be stored
editor.commit();
finish();
fetch...
SharedPreferences prefs = this.getSharedPreferences("msh", Context.MODE_PRIVATE);
uida = prefs.getString("id", "");
写入共享首选项
SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putInt(getString(R.string.saved_high_score), newHighScore);
editor.commit();
从共享首选项读取
SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int defaultValue = getResources().getInteger(R.string.saved_high_score_default);
long highScore = sharedPref.getInt(getString(R.string.saved_high_score), defaultValue);