问题描述
所以练习1我点击一个按钮，带我去的活动2.在活动2我输入一些数据到一个EditText。当我打它带我到活动1这是正确的手机上的后退按钮，但如果我打的活动1按钮再次，我进入的EditText任何文本已经一去不复返了。我相信这是因为我是一个新的意图每一次我打我的按钮启动，我想我需要使用标志，但我不能肯定。下面是我的基本MainActivity1和MainActivity2没有code我想，没有工作。
So on activity 1 I click a button that takes me to activity 2. In activity 2 I enter some data into an EditText. When I hit the back button on the phone it takes me to activity 1 which is correct but if I hit the activity 1 button again any text that I entered into the EditText is gone. I am sure this is because I am starting a new Intent every time I hit my button and I think I need to be using Flags but I am not certain. Below is my basic MainActivity1 and MainActivity2 without the code I tried that didn't work.
**编辑：退出所有保存的数据需要被删除的应用程序后，
** After exiting the app all saved data needs to be deleted.
MainActivity1
MainActivity1
public class MainActivity extends Activity {
Button b1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button)findViewById(R.id.button2);
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent i = new Intent(MainActivity.this,MainActivity2.class);
startActivity(i);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
MainActivity2
MainActivity2
public class MainActivity2 extends Activity {
EditText et1;
@Override
protected void onCreate(Bundle outState) {
super.onCreate(outState);
setContentView(R.layout.activity_main_2);
et1 = (EditText)findViewById(R.id.editText1);
}
}
}
感谢你在前进。
推荐答案
试试这个复制这些codeS在MainActivity2这将节省您的数据（即你的EditText数据）
Try thiscopy these codes in your MainActivity2 it will save your data (i.e. your EditText Data)
public class MainActivity2 extends Activity {
EditText et1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_2);
et1 = (EditText)findViewById(R.id.editText1);
loadSavedPreferences();
}
private void loadSavedPreferences() {
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(this);
et1.setText(sharedPreferences.getString("string_et1",""));
}
private void savePreferences(String key, String value) {
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(this);
Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
public void saveData(){
savePreferences("string_et1", et1.getText().toString());
}
@Override
public void onBackPressed(){
saveData();
super.onBackPressed();
}
}
如果你想删除preferences退出应用程序尝试在你的MainActivity1的时候。
if you want to delete the preferences when exiting the app try this in your MainActivity1.
public class MainActivity extends Activity {
Button b1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button)findViewById(R.id.button2);
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent i = new Intent(MainActivity.this,MainActivity2.class);
startActivity(i);
}
});
}
@Override
public void onBackPressed() {
clear_pref();
}
public void clear_pref(){
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(this);
Editor editor = sharedPreferences.edit();
editor.clear();
editor.commit();
}
}
这篇关于打后退按钮时保存数据的EditText的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！