Question

我遇到了一个奇怪的问题，我在xml中只有EditText个框，我给它们提供了默认值。我也在使用共享首选项，其中我保存用户输入的值。

问题是在模拟器中EditText工作正常但在实际物理设备上的值是空的，我错过了什么？

  <EditText
       android:id="@+id/etTRQPO"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:ems="10"
       android:inputType="numberDecimal"
       android:singleLine="true"
       android:text="15">
  </EditText>

java代码

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Getacc extends Activity {
    Button save6;

    EditText edtTRQPO, edtTRQGE, edtTRQFW, edtTRQGR, edtTRQBN, edtTRQLT,
            edtTRQPP, edtTRQCG;
    int tV, tW, tX, counterAC;
    String tsTRQPO, tsTRQGE, tsTRQFW, tsTRQGR, tsTRQBN, tsTRQLT, tsTRQPP,
            tsTRQCG;
    public static String FILE1 = "MyPrefsFile";
    SharedPreferences abcPref;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.getacc);
        save6 = (Button) findViewById(R.id.btGoresult);
        edtTRQPO = (EditText) findViewById(R.id.etTRQPO);
        edtTRQGE = (EditText) findViewById(R.id.etTRQGE);
        edtTRQFW = (EditText) findViewById(R.id.etTRQFW);
        edtTRQGR = (EditText) findViewById(R.id.etTRQGR);
        edtTRQBN = (EditText) findViewById(R.id.etTRQBN);
        edtTRQLT = (EditText) findViewById(R.id.etTRQLT);
        edtTRQPP = (EditText) findViewById(R.id.etTRQPP);
        edtTRQCG = (EditText) findViewById(R.id.etTRQCG);

        abcPref = getSharedPreferences(FILE1, 0);
        edtTRQPO.setText(abcPref.getString("tsTRQPO", ""));
        edtTRQGE.setText(abcPref.getString("tsTRQGE", ""));
        edtTRQFW.setText(abcPref.getString("tsTRQFW", ""));
        edtTRQGR.setText(abcPref.getString("tsTRQGR", ""));
        edtTRQBN.setText(abcPref.getString("tsTRQBN", ""));
        edtTRQLT.setText(abcPref.getString("tsTRQLT", ""));
        edtTRQPP.setText(abcPref.getString("tsTRQPP", ""));
        edtTRQCG.setText(abcPref.getString("tsTRQCG", ""));

        save6.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if ((!edtTRQPO.getText().toString().equals(""))
                        && (!edtTRQGE.getText().toString().equals(""))
                        && (!edtTRQFW.getText().toString().equals(""))
                        && (!edtTRQGR.getText().toString().equals(""))
                        && (!edtTRQBN.getText().toString().equals(""))
                        && (!edtTRQLT.getText().toString().equals(""))
                        && (!edtTRQPP.getText().toString().equals(""))
                        && (!edtTRQCG.getText().toString().equals(""))) {
                    // TODO Auto-generated method stub
                    counterAC =1;
                    abcPref = getSharedPreferences(FILE1, 0);
                    SharedPreferences.Editor editor = abcPref.edit();
                    editor.putString("tsTRQPO", edtTRQPO.getText().toString());
                    editor.putString("tsTRQGE", edtTRQGE.getText().toString());
                    editor.putString("tsTRQFW", edtTRQFW.getText().toString());
                    editor.putString("tsTRQGR", edtTRQGR.getText().toString());
                    editor.putString("tsTRQBN", edtTRQBN.getText().toString());
                    editor.putString("tsTRQLT", edtTRQLT.getText().toString());
                    editor.putString("tsTRQPP", edtTRQPP.getText().toString());
                    editor.putString("tsTRQCG", edtTRQCG.getText().toString());
                    editor.putInt("counterac", counterAC);
                    editor.commit();
                    Toast message = Toast.makeText(Getacc.this,
                            "Values are saved", 2000);
                    message.setGravity(Gravity.BOTTOM, 0, 0);
                    message.show();
                    Intent opentime = new Intent("com.sports.sport.TIME");
                    startActivity(opentime);
                    onPause();
                } else {
                    Toast failz = Toast.makeText(Getacc.this,
                            "Values are not Entered", 2000);
                    failz.setGravity(Gravity.BOTTOM, 0, 0);
                    failz.show();
                }
            };
        });

    }
}

Answer 1

首次在真实设备上运行app时，它将显示默认值，而不是SharedPreferences中的值，因为SharedPreferences中的值为空。如果SharedPreferences具有空值，当您打开第二个应用程序时，EditText将显示SharedPreferences中的空值。您需要应用一些值检查，如

 if(user_entered_values_in_edittext){
    //Store values in SharedPreferences otherwise not.
 }

 // On app resume - inside onResume() or onCreate()
 if(SharedPreferences have empty value or no value){
    //Show your EditText default value that you have defined in xml file.
 }

更正了Getacc.java文件...

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class Getacc extends Activity {
   Button save6;

   EditText edtTRQPO, edtTRQGE, edtTRQFW, edtTRQGR, edtTRQBN, edtTRQLT,
        edtTRQPP, edtTRQCG;
   int tV, tW, tX, counterAC;
   String tsTRQPO, tsTRQGE, tsTRQFW, tsTRQGR, tsTRQBN, tsTRQLT, tsTRQPP,
        tsTRQCG;
   public static String FILE1 = "MyPrefsFile";
   SharedPreferences abcPref;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.getacc);
    save6 = (Button) findViewById(R.id.btGoresult);
    edtTRQPO = (EditText) findViewById(R.id.etTRQPO);
    edtTRQGE = (EditText) findViewById(R.id.etTRQGE);
    edtTRQFW = (EditText) findViewById(R.id.etTRQFW);
    edtTRQGR = (EditText) findViewById(R.id.etTRQGR);
    edtTRQBN = (EditText) findViewById(R.id.etTRQBN);
    edtTRQLT = (EditText) findViewById(R.id.etTRQLT);
    edtTRQPP = (EditText) findViewById(R.id.etTRQPP);
    edtTRQCG = (EditText) findViewById(R.id.etTRQCG);

    abcPref = getSharedPreferences(FILE1, 0);

    // First get All values stored in SharedPreferences 
      tsTRQPO = abcPref.getString("tsTRQGE", null);
      tsTRQGE = abcPref.getString("tsTRQGE", null);
      tsTRQFW = abcPref.getString("tsTRQFW", null);
      tsTRQGR = abcPref.getString("tsTRQGR", null);
      tsTRQBN = abcPref.getString("tsTRQBN", null);
      tsTRQLT = abcPref.getString("tsTRQLT", null);
      tsTRQPP = abcPref.getString("tsTRQPP", null);
      tsTRQCG = abcPref.getString("tsTRQCG", null);

      // Check if values are not null
      if(tsTRQPO != null && tsTRQGE != null && tsTRQFW != null && tsTRQGR!= null && tsTRQBN != null && tsTRQLT != null && tsTRQPP != null && tsTRQCG != null){
          edtTRQPO.setText(tsTRQPO);
          edtTRQGE.setText(tsTRQGE);
          edtTRQFW.setText(tsTRQFW);
          edtTRQGR.setText(tsTRQGR);
          edtTRQBN.setText(tsTRQBN);
          edtTRQLT.setText(tsTRQLT);
          edtTRQPP.setText(tsTRQPP);
          edtTRQCG.setText(tsTRQCG);

      }else{
        //Do nothing.. EditText will show Default values defined in xml file
      }

    save6.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            if ((!edtTRQPO.getText().toString().equals(""))
                    && (!edtTRQGE.getText().toString().equals(""))
                    && (!edtTRQFW.getText().toString().equals(""))
                    && (!edtTRQGR.getText().toString().equals(""))
                    && (!edtTRQBN.getText().toString().equals(""))
                    && (!edtTRQLT.getText().toString().equals(""))
                    && (!edtTRQPP.getText().toString().equals(""))
                    && (!edtTRQCG.getText().toString().equals(""))) {
                // TODO Auto-generated method stub
                counterAC =1;
                abcPref = getSharedPreferences(FILE1, 0);
                SharedPreferences.Editor editor = abcPref.edit();
                editor.putString("tsTRQPO", edtTRQPO.getText().toString());
                editor.putString("tsTRQGE", edtTRQGE.getText().toString());
                editor.putString("tsTRQFW", edtTRQFW.getText().toString());
                editor.putString("tsTRQGR", edtTRQGR.getText().toString());
                editor.putString("tsTRQBN", edtTRQBN.getText().toString());
                editor.putString("tsTRQLT", edtTRQLT.getText().toString());
                editor.putString("tsTRQPP", edtTRQPP.getText().toString());
                editor.putString("tsTRQCG", edtTRQCG.getText().toString());
                editor.putInt("counterac", counterAC);
                editor.commit();
                Toast message = Toast.makeText(Getacc.this,
                        "Values are saved", 2000);
                message.setGravity(Gravity.BOTTOM, 0, 0);
                message.show();
                Intent opentime = new Intent("com.sports.sport.TIME");
                startActivity(opentime);
                onPause();
            } else {
                Toast failz = Toast.makeText(Getacc.this,
                        "Values are not Entered", 2000);
                failz.setGravity(Gravity.BOTTOM, 0, 0);
                failz.show();
            }
        };
    });
  }
}

Answer 2

共享首选项保存在缓存中。如果从IDE重新启动应用程序，则不会清除共享首选项。如果你想清除它，你应该

卸载应用
转到seettings＆gt;节目＆gt;找到你的程序＆gt;清除缓存。

只有那时它才是空的。所以也许你的问题是你在模拟器和设备上有旧值它是新的（反之亦然）

Answer 3

第一次，应用程序中没有SharedPreferences，因此abcPref.getString("tsTRQPO", "")和其他人会导致此处给出的空默认值。通过填写所有编辑文本保存数据后，您将从下次开始正确处理数据。

要进行检查，请尝试从SharedPreferences获取数据时设置一些默认值。对于ex edtTRQPO.setText(abcPref.getString("tsTRQPO", "15"));并检查它是否第一次加载值为15。

Answer 4

这是因为你试图从SharedPreferences获取OnCreate方法的值，当前有空白意味着null，现在来看，当你启动你的应用程序时，它将首先执行OnCreate方法，在你尝试从sharedPreferences获取值时，当你在save6.setOnClickListener上保存值时

是什么？

注意：在sharedPreferences中保存后获取值

edittext默认值来自模拟器而非设备上

4 个答案: