如何将单选按钮转换为字符串并将其存储到数据库中?

Question

>编辑：这篇文章现在已经解决了。但是，有新的错误。当我选择"女性"时，当我转到"查看记录"页面时，它显示我选择了"男性"。

添加记录(性别(

查看记录(性别(

我正在尝试使用Android Studio制作一个应用程序，该应用程序获取学生的信息并将其存储在数据库中。这些信息的一部分是学生的性别。

当学生选择单选按钮(男性或女性(时，该选择将添加到数据库中。

我尝试过对其进行编码，但是每当我打开它时，我的应用程序都会崩溃......

这是布局代码 (xml(。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="40dp"
android:background="#F0F8FF"
>
<TableLayout
android:id="@+id/add_table"
android:layout_width="match_parent"
android:layout_height="606dp"
android:paddingTop="40dp">
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:text="Student ID:" />
<EditText
android:id="@+id/sid"
android:layout_width="190dp"
android:layout_height="wrap_content" />
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:text="First Name:" />
<EditText
android:id="@+id/fn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minWidth="150dip" />
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:text="Last Name:" />
<EditText
android:id="@+id/ln"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minWidth="150dip" />
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:layout_marginTop="5dp"
android:text="Gender:" />
<RadioGroup
android:id="@+id/ge"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:orientation="horizontal">
<RadioButton
android:id="@+id/male"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleX="0.9"
android:scaleY="0.9"
android:checked="true"
android:text="Male" />
<RadioButton
android:id="@+id/female"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:scaleX="0.9"
android:scaleY="0.9"
android:text="Female" />
</RadioGroup>
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:text="Course Study:" />
<EditText
android:id="@+id/cs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minWidth="150dip" />
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:digits="0123456789"
android:inputType="number"
android:padding="3dip"
android:text="Age:" />
<EditText
android:id="@+id/ag"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minWidth="150dip" />
</TableRow>
<TableRow>
<TextView
android:layout_marginLeft="25dp"
android:padding="3dip"
android:text="Address:" />
<EditText
android:id="@+id/ad"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minWidth="150dip" />

</TableRow>
<Button
android:id="@+id/add_button"
android:layout_width="207dp"
android:layout_height="wrap_content"
android:layout_marginLeft="118dp"
android:layout_marginRight="52dp"
android:layout_marginTop="14dp"
android:padding="6dip"
android:text="Add Student" />
<ImageView
android:id="@+id/imageView4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
app:srcCompat="@mipmap/man" />
</TableLayout>
</LinearLayout>

这是主要活动(java代码(

public class Addrecord extends AppCompatActivity {
DatabaseManager myDb;
EditText sid, fn, ln, cs, ag, ad;
RadioGroup radioGenderGroup;
RadioButton radioGenderButton;
Button btnAddStudent;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle(null);
myDb = new DatabaseManager(this);
sid = (EditText)findViewById(R.id.sid);
fn = (EditText)findViewById(R.id.fn);
ln = (EditText)findViewById(R.id.ln);
radioGenderGroup = (RadioGroup) findViewById(R.id.ge);
int selectedid = radioGenderGroup.getCheckedRadioButtonId();
radioGenderButton = (RadioButton) findViewById(selectedid);

cs = (EditText)findViewById(R.id.cs);
ag = (EditText)findViewById(R.id.ag);
ad = (EditText)findViewById(R.id.ad);
btnAddStudent = (Button)findViewById(R.id.add_button);
AddStudentRecord();

}

public  void AddStudentRecord() {
btnAddStudent.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean isInserted = myDb.insertDataStudent(
Integer.parseInt(sid.getText().toString()),
fn.getText().toString(),
ln.getText().toString(),
radioGenderButton.getText().toString(),
cs.getText().toString(),
Integer.parseInt(ag.getText().toString()),
ad.getText().toString()
);
if(isInserted == true)
Toast.makeText(Addrecord.this,"Data Inserted",Toast.LENGTH_LONG).show();
else
Toast.makeText(Addrecord.this,"Data not Inserted",Toast.LENGTH_LONG).show();
}
}
);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.screen2_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.home2) {
Intent intent = new Intent(Addrecord.this, Home.class);
startActivity(intent);
return true;
}
return super.onOptionsItemSelected(item);
}
}

这是数据库(java(

public class DatabaseManager extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "student";
public static final String TABLE_NAME1 = "studentinfo";
public static final String TABLE_NAME2 = "taskinfo";
public static final String TABLE_NAME3 = "examinfo";
//student information
public static final String COL_0student = "IDstudent";
public static final String COL_1student = "studentId";
public static final String COL_2student = "firstname";
public static final String COL_3student = "lastname";
public static final String COL_4student = "gender";
public static final String COL_5student = "coursestudy";
public static final String COL_6student = "age";
public static final String COL_7student = "address";

//task information
public static final String COL_0task = "IDtask";
public static final String COL_1task = "taskname";
public static final String COL_2task = "location";
//public static final String COL_3task = "status";
//exam information (no need for Id since no selection happening)
public static final String COL_1exam = "unitname";
public static final String COL_2exam = "date";
public static final String COL_3exam = "time";
public static final String COL_4exam = "location3";

public DatabaseManager(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table if not exists " + TABLE_NAME1 + " (IDstudent INTEGER PRIMARY KEY AUTOINCREMENT,studentId INTEGER,firstname TEXT,lastname TEXT, gender TEXT, coursestudy TEXT, age INTEGER, address TEXT)");
db.execSQL("create table if not exists " + TABLE_NAME2 + " (IDtask INTEGER PRIMARY KEY AUTOINCREMENT, taskname TEXT,location TEXT,status TEXT)");
db.execSQL("create table if not exists " + TABLE_NAME3 + " (unitname TEXT,date TEXT,time TEXT, location TEXT)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME1);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME2);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME3);
onCreate(db);
}

//INSERT, UPDATE, SELECT, DELETE student record

public boolean insertDataStudent(Integer studentId, String firstname, String lastname, String gender, String coursestudy, Integer age, String address) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues newStudent = new ContentValues();
newStudent.put(COL_1student, studentId);
newStudent.put(COL_2student, firstname);
newStudent.put(COL_3student, lastname);
newStudent.put(COL_4student, gender);
newStudent.put(COL_5student, coursestudy);
newStudent.put(COL_6student, age);
newStudent.put(COL_7student, address);
long result = db.insert(TABLE_NAME1, null, newStudent);
if (result == -1)
return false;
else
return true;
}
public Cursor getAllDataStudent() {
SQLiteDatabase db = this.getWritableDatabase();
Cursor res = db.rawQuery("select * from " + TABLE_NAME1, null);
return res;
}

public boolean updateDataStudent(String idstudent, String studentId, String firstname, String lastname, String gender, String coursestudy, String age, String address) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues newStudent = new ContentValues();
newStudent.put(COL_0student, idstudent);
newStudent.put(COL_1student, studentId);
newStudent.put(COL_2student, firstname);
newStudent.put(COL_3student, lastname);
newStudent.put(COL_4student, gender);
newStudent.put(COL_5student, coursestudy);
newStudent.put(COL_6student, age);
newStudent.put(COL_7student, address);
db.update(TABLE_NAME1, newStudent, "IDstudent = ?", new String[]{idstudent});
return true;
}
public Integer deleteDataStudent(String idstudent) {
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME1, "IDstudent = ?", new String[]{idstudent});
}
}

这是错误日志

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.supriya.project3, PID: 5517
java.lang.RuntimeException: Unable to start activity   ComponentInfo{com.supriya.project3/com.supriya.project3.Addrecord}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.widget.RadioButton.getText()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.widget.RadioButton.getText()' on a null object reference
at com.supriya.project3.Addrecord.onCreate(Addrecord.java:42)
at android.app.Activity.performCreate(Activity.java:7009)
at android.app.Activity.performCreate(Activity.java:7000)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856) 
at android.app.ActivityThread.-wrap11(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
at     com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
I/zygote: Do full code cache collection, code=98KB, data=54KB
After code cache collection, code=93KB, data=45KB
Application terminated.

Answer 1

解决方案：

首先，将RadioButton中的任何一个设置为：

android:checked="true" 

所以它应该看起来像：

<RadioButton
android:id="@+id/male"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleX="0.9"
android:scaleY="0.9"
android:text="Male"
android:checked="true" />

默认情况下，这将为您提供Male文本String gender.

其次，从这部分中删除此行：String gender = String.valueOf(radioGenderButton.getText());。

radioGenderGroup = (RadioGroup) findViewById(R.id.ge);
int selectedid = radioGenderGroup.getCheckedRadioButtonId();
radioGenderButton = (RadioButton) findViewById(selectedid);
String gender = String.valueOf(radioGenderButton.getText()); // REVOME THIS

然后

写这个：

radioGenderGroup = (RadioGroup) findViewById(R.id.ge);
int selectedid = radioGenderGroup.getCheckedRadioButtonId();
radioGenderButton = (RadioButton) findViewById(selectedid);

内部onClick()如图所示：

btnAddStudent.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
.... (Write those 3 lines here)
boolean isInserted = myDb.insertDataStudent(
Integer.parseInt(sid.getText().toString()),
fn.getText().toString(),
ln.getText().toString(),
radioGenderButton.getText().toString(),
cs.getText().toString(),
Integer.parseInt(ag.getText().toString()),
ad.getText().toString()
);
if(isInserted == true)
Toast.makeText(Addrecord.this,"Data Inserted",Toast.LENGTH_LONG).show();
else
Toast.makeText(Addrecord.this,"Data not Inserted",Toast.LENGTH_LONG).show();
}
}
);

通过上述步骤，您将获得您选择的任何gender，然后将其传递给数据库进行插入。

希望对您有所帮助。

Answer 2

在 onCreate 方法中

radioGenderGroup = (RadioGroup) findViewById(R.id.ge);
radioGenderGroup .setOnCheckedChangeListener(this);

然后重写 onCheckedChanged 方法

@Override
public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
switch (group.getId()) {
case R.id.male:
gender = "Male";
break;
case R.id.female:
gender = "Female";
break;
}
}

Answer 3

如果您正在寻找如何从无线电组捕获输入。这里有一点提示给你。您还需要获取单选按钮 ID 并实现侦听器。就这样。

radioGenderGroup = (RadioGroup) findViewById(R.id.ge);
//Get also male and Female (RadioButton) id from the layout.
radioGenderGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
// checkedId is the RadioButton selected
if (rdoMale.getId() == checkedId) {                   
//Get the value for male R.Button.rdoMale
} else if (rdoFemale.getId() == checkedId) {              
//Get the value for Female R.Button.rdoFemale
}
}
});