根据输入呼出句子

Question

我是开发Android应用程序的新手，目前正在开发需要用户输入大量数据并将其保存在sharedPreferences作为数据库的android软件。 这是我的编码示例：

public static final String DEFAULT= "no data found";

然后：

protected void storeData(SharedPreferences.Editor editor, String key, EditText et) {
    String content = et.getText().toString();
    if ("".equals(content)) {
        editor.remove(key);
    } else {
        editor.putString(key, content);
    }
}

为了节省用户输入：

    public void OnClickSave(){
            button17=(Button)findViewById(R.id.button17);
            button17.setOnClickListener(
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            name = (EditText) findViewById(R.id.name);
                            gender = (EditText) findViewById(R.id.gender);
                            age = (EditText) findViewById(R.id.age);
                            fruit = (EditText) findViewById(R.id.fab_fruit);
                            music = (EditText) findViewById(R.id.fab_music);
 SharedPreferences sharedPreferences = getSharedPreferences("Database", Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor = sharedPreferences.edit();
                        storeData(editor,"name", name);
                        storeData(editor,"gender", gender);
                        storeData(editor,"age", age);
                        storeData(editor,"fruit", fruit);
                        storeData(editor,"music", music);
                        editor.commit();
                        Toast.makeText(MainActivity7.this, "Data was saved!!!", Toast.LENGTH_SHORT).show();
                    }
                }
        );
    }

为了加载数据，我做了这样的事情：

public void OnClickLoad(){
            button38=(Button)findViewById(R.id.button38);
            button38.setOnClickListener(
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
    SharedPreferences sharedPreferences = getSharedPreferences("Database", Context.MODE_PRIVATE);
            String name = sharedPreferences.getString("name", DEFAULT);
            String gender = sharedPreferences.getString("gender", DEFAULT);
            String age = sharedPreferences.getString("age", DEFAULT);
            String fruit = sharedPreferences.getString("fruit", DEFAULT);
            String music = sharedPreferences.getString("music", DEFAULT);
             }
                    }
            );
AlertDialog.Builder a_builder = new AlertDialog.Builder(MainActivity12.this);
            a_builder.setMessage(
                    "Data 1 name is :"+ name + "\n"+ 
                    "Data 1 gender is :"+ gender + "\n"+ 
                    "Data 1 age is :"+ age + "\n"+ 
                    "Data 1 favorite fruit is :"+ fruit + "\n"+ 
                    "Data 1 favorite music is :"+ music + "\n"+ 
)

                    .setCancelable(false)
                    .setPositiveButton("Proceed", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            dialog.cancel();
                        }
                    })
                    .setNegativeButton("Return", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            dialog.cancel();
                        }
                    })
            ;
            AlertDialog alert= a_builder.create();
            alert.setTitle("Checking");
            alert.show();
        }

因为我已经在构建器中设置了句子，所以当用户未回答任何一个问题时，输出将变为

                Data 1 name is : Sample1
                Data 1 gender is : male 
                Data 1 age is : no data found 
                Data 1 favorite fruit is : apple 
                Data 1 favorite music is : no data found

我想知道是否还有其他方法，这样，如果用户未输入任何内容，相关的句子将不会显示，如下所示：

        Data 1 name is : Sample1
        Data 1 gender is : Male
        Data 1 favorite fruit is : apple 

这是编码示例，在我的应用程序中，我要求用户输入20-30数据。 感谢inad谁愿意提供帮助。 *对于标题引起的混乱，我们深表歉意，因为我不确定该指的是什么。

Answer 1

可以使用null作为默认值，而不是使用默认的String作为您的首选项：

String name = sharedPreferences.getString("name", null);
String gender = sharedPreferences.getString("gender", null);
// ...

之后，您可以简单地执行null值检查并相应地构造您的消息：

StringBuilder messageBuilder = new StringBuilder();

if(name != null) {
    messageBuilder.append("Data 1 name is: " + name);
    messageBuilder.append("\n");
}
if(gender != null) {
    messageBuilder.append("Data 1 gender is: " + gender);
    messageBuilder.append("\n");
}
// ...

a_builder.setMessage(messageBuilder.toString());