无法保存具有共享首选项的字符串

Question

我有两个字符串要保存，我编写了如下代码

public class MainActivity extends Activity {
    Button result;
    EditText b951, b9511, sum95, t95, p95

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {   
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        LoadPreferences();
        result = (Button)findViewById(R.id.btn1);
        b951 = (EditText)findViewById(R.id.b951);
        b9511 = (EditText)findViewById(R.id.b9511);
        sum95 = (EditText)findViewById(R.id.sum95);
        p95 = (EditText)findViewById(R.id.p95);
        t95 = (EditText)findViewById(R.id.t95);     
    }

    public void close (View v){
        SavePreferences("p2b951", b951.getText().toString());
        SavePreferences("p2b9511", b9511.getText().toString());

        finish();
    }

    private void SavePreferences(String key, String value){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
    }

    private void LoadPreferences(){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
        String p1b951 = sharedPreferences.getString("p2b951", "1");
        String p1b9511 = sharedPreferences.getString("p2b9511", "1");

        b951.setText(p1b951);
        b9511.setText(p1b9511);
    }


    public void result (View v) {   
        try {       
            int ib951 = Integer.parseInt(b951.getText().toString());                
            int ib9511 = Integer.parseInt(b9511.getText().toString());          

            int iisum95 = (ib9511-ib951);
            sum95.setText(String.valueOf(iisum95));

            int isum95 = Integer.parseInt(sum95.getText().toString());

            int ip95 = Integer.parseInt(p95.getText().toString());

            int pp95 = (isum95*ip95);
            t95.setText(String.valueOf(pp95));
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }
}

但是这两行似乎有问题：

b951.setText(p1b951);
b9511.setText(p1b9511);

我试过了

b951.setText(String.valueOf.p1b951);
b9511.setText(String.valueOf.p1b9511);

而且问题仍然存在

当我打开应用程序并调用loadpreferences时，该应用程序将强制关闭

logcat告诉我，这两行的错误是肯定的，因为这只是第一行，因为他没有得到第二行，但是它们是相同的，所以写错了

有帮助吗？

Answer 1

更改onCreate（），如下所示：

@Override
public void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    result = (Button)findViewById(R.id.btn1);
    b951 = (EditText)findViewById(R.id.b951);
    b9511 = (EditText)findViewById(R.id.b9511);
    sum95 = (EditText)findViewById(R.id.sum95);
    p95 = (EditText)findViewById(R.id.p95);
    t95 = (EditText)findViewById(R.id.t95);   
    LoadPreferences();  
}

这是因为您在LoadPreferences（）中使用EditTexts而不在EditTexts上调用findViewById（）。

Answer 2

您可以遵循类似的代码并从中获得帮助。 如

在首选项中设置值：

SharedPreferences.Editor editor = getSharedPreferences(MODE_PRIVATE).edit();
 editor.putString("name", "Elena");
 editor.putInt("idName", 12);
 editor.commit();

从首选项中检索数据：

SharedPreferences prefs = getSharedPreferences(MODE_PRIVATE); 
String restoredText = prefs.getString("text", null);
if (restoredText != null) {
  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.
}

它对此有任何困惑，然后点击此链接