java - SharedPreferences 使程序崩溃

Question

我正在制作这个需要用户名才能运行的程序。在设置中， Intent 工作正常，直到我添加共享首选项代码。我可能把它添加到了错误的地方。否则 Intent 工作得很好。共享首选项也没有保存字符串。它一直在崩溃。有什么想法吗？

package com.XXX.XXX;

import android.app.Activity;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class Settings extends Activity{

EditText nameXML;
SharedPreferences filename;
public  String name;
String filenamename = "nameFile";
Button save = (Button) findViewById(R.id.button1);

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_settings);
    nameXML = (EditText) findViewById(R.id.editText1);
    filename = getSharedPreferences(filenamename,0);
    String username = filename.getString("nameString", "Master Traders");
    nameXML.setHint(username);
    name = nameXML.getText().toString();
    save.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Editor nameEditor = filename.edit();
            nameEditor.putString("nameString", name);
            nameEditor.commit();
        }
    });
}
@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();

}




}

Answer 1

Button save = (Button) findViewById(R.id.button1);

更改为:

    Button save;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        save  = (Button) findViewById(R.id.button1);//this line is before onclicklistener.
 save.setOnclickListner(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            name = nameXML.getText().toString(); 
            Editor nameEditor = filename.edit();
            nameEditor.putString("nameString", name);
            nameEditor.commit();
        }
    });
    }

您应该发布 logcat 以进一步了解问题所在。但很可能是由于@Reid 提出的。添加了新的更新代码。