更新时间:2022-04-22 22:31:37
您的问题的解决方案如下:
the solution to your problem is as follows:
由于此链接,我也尝试并重新编写了代码:
I tried and reworked your code also thanks to this link:
public class MainActivity extends ListActivity {
private static final String SHARED_PREFS_NAME = "MY_SHARED_PREF";
ArrayList<String> mylist = new ArrayList<String>();
ArrayAdapter<String> adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listview = (ListView) findViewById(R.id.list);
Button btn = (Button) findViewById(R.id.button);
//NOTE: acquire array from shared preferences
mylist = getArray();
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mylist);
OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
EditText edit = (EditText) findViewById(R.id.edittext);
mylist.add(edit.getText().toString());
edit.setText("");
adapter.notifyDataSetChanged();
}
};
btn.setOnClickListener(listener);
listview.setAdapter(adapter);
}
public boolean saveArray() {
SharedPreferences sp = this.getSharedPreferences(SHARED_PREFS_NAME, Activity.MODE_PRIVATE);
SharedPreferences.Editor mEdit1 = sp.edit();
Set<String> set = new HashSet<String>();
set.addAll(mylist);
mEdit1.putStringSet("list", set);
return mEdit1.commit();
}
public ArrayList<String> getArray() {
SharedPreferences sp = this.getSharedPreferences(SHARED_PREFS_NAME, Activity.MODE_PRIVATE);
//NOTE: if shared preference is null, the method return empty Hashset and not null
Set<String> set = sp.getStringSet("list", new HashSet<String>());
return new ArrayList<String>(set);
}
}
..并在关闭应用程序之前调用SaveArray()
..and calls SaveArray () before closing the application
public void onStop() {
saveArray();
super.onStop();
}
或者,每次添加元素时保存数组(all'onclick按钮会覆盖当前列表中的共享首选项)
or, alternatively, save the array every time you add an element (all'onclick button overwrites the shared preference in the current list)