Question

我正在创建一个具有3个EditTexts的android应用程序。现在，当我关闭应用程序并返回它时，EditText中的值消失了，我必须返回上次输入的值。

如何在EditText中返回用户输入的值（按下按钮），以便用户在关闭和响应应用时不必一次又一次地输入整个文本？

提供代码的答案将有很大帮助！感谢。

Answer 1

将此课程放在您的项目中

public class SaveData {

private static final String EDIT1 = "edit1";
private static final String EDIT2 = "edit2";
private static final String EDIT3 = "edit3";
SharedPreferences pref;
Editor editor;
Context mContext;
// Shared pref mode
int PRIVATE_MODE = 0;

public SaveData(Context context) {
    this.mContext = context;

    // Sharedpref file name
    final String PREF_NAME = mContext.getString(R.string.app_name) + "_pref";
    pref = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = pref.edit();
}

public String getEditText1() {
    return pref.getString(EDIT1, "");
}

public void setEditText1(String text)  {
    editor.putString(EDIT1, text);
    editor.commit();
}

public String getEditText2() {
    return pref.getString(EDIT2, "");
}

public void setEditText2(String text){
    editor.putString(EDIT2, text);
    editor.commit();
}

public String getEditText3() {
    return pref.getString(EDIT3, "");
}

public void setEditText3(String text) {
    editor.putString(EDIT3, text);
    editor.commit();
}
}

现在onCreate把这个

SaveData saveData = new SaveData(this);
mEditText1.setText(saveData.getEditText1());
mEditText2.setText(saveData.getEditText2());
mEditText3.setText(saveData.getEditText3());

在onPause

SaveData saveData = new SaveData(this);
saveData.setEditText1(mEditText1.getText()+"");
saveData.setEditText2(mEditText2.getText()+"");
saveData.setEditText3(mEditText3.getText()+"");

Answer 2

有几种方法可以存储此类型的数据，我个人会使用数据库表，特别是如果您准备好将数据库作为应用程序的一部分。如果不考虑写入和字符串数组来存档和阅读它。

如果您正在查看数据库选项，请执行类似

的操作

// on create
String createTable = "CREATE TABLE texts (id INT NOT NULL,words TEXT)";
SQLiteDatabase db =  MyDatabaseHelper.getDB(); // <- use the method you use to get a db.
db.exec(createTable);
db.close();


 // on start up of your edit text activity

 // create array of edit texts which you have initialized via their ids, it must be a member variable
 EditText[] editTexts = new EditText[]{editText1,editText2,editText3};

 SQLiteDatabase db;
 String sql= "SELECT * from texts";
 Cursor c = db.rawQuery(sql,null);
 if(null !=c && c.moveToFirst())
 {
      for(int i = 0;  i<c.getCount();  i++)
      {
          // get data from db
          String text = c.getString(1);
          int id = c.getInt(0);
          editTexts[id].setText(text);
      }
 }



// to be called at the end of the activity or when then edit texts change
private void saveToDb(){
    SQLiteDataBase db; // got from your sqlite helper method

    for(int i =0; i<editTexts.length; i++)
    {
        // check for insert
        String check = "SELECT *  FROM texts WHERE id ="+i;
        String ins;
        Cursor c = db.rawQuery(check,null);
        if(null != c && c.moveToFirst()){
        // update
           ins= "UPDATE texts SET words = '"+editTexts[i].getText().toString+"' WHERE id = "+i+";";
        }else{
        // insert
           ins = "INSERT into texts (id,words) VALUES("+i+",'"+editTexts[i].getText().toString+"');";
        }
        db.exec(ins);
        db.close();
    }
}

我在没有将其作为指导测试的情况下编写了这个，我之前已经多次使用过这种模式并且效果很好

如何在重新打开应用程序时保留EditText值？

2 个答案: