Question

当我运行应用程序时，我得到：跳过90帧。应用程序可能在其主线程上工作太多。

主要代码：

public class Student_Data extends Activity implements OnClickListener { 
EditText studentName, StuClass;
    Button b1;
    String NameStudent;
    String ClassStudent;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_student__data);

        studentName= (EditText) findViewById(R.id.editText1);
        StuClass= (EditText) findViewById(R.id.editText2);        
        NameStudent = studentName.getText().toString();
        ClassStudent = StuClass.getText().toString();        
        b1=(Button) findViewById(R.id.button1);                
        b1.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        //TODO Auto-generated method stub
        insertData(NameStudent, ClassStudent);
    }

    private void insertData(String nameStudent2, String classStudent2) {
        // TODO Auto-generated method stub
        AndroidDbHelper helper = new AndroidDbHelper(this);
        SQLiteDatabase database = helper.getWritableDatabase();
        ContentValues content = new ContentValues();
        content.put(AndroidDbHelper.COLUMN_NAME, NameStudent);
        content.put(AndroidDbHelper.COLUMN_CLASS, ClassStudent);

        database.insert(AndroidDbHelper.TABLE_NAME, null, content);
    }  
}

AndroidDbHelper.java

public class AndroidDbHelper extends SQLiteOpenHelper {
    public static final String DB_NAME = "StudentData";
    public static final int DB_VERSION = 1;

    public static final String TABLE_NAME = "student";
    public static final String COLUMN_NAME= "name";
    public static final String COLUMN_CLASS= "cclass";

    public AndroidDbHelper(Context context) {
        super(context, DB_NAME, null, 1);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String CreateTable = "CREATE TABLE" + TABLE_NAME + "(" + COLUMN_NAME + "TEXT," + COLUMN_CLASS + "TEXT" + ");";
        // TODO Auto-generated method stub
        db.execSQL(CreateTable);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " +TABLE_NAME );       
        onCreate(db);
    }

}

虽然，我正在获取主要活动页面以在模拟器上插入值。但如果我插入值，我会在logcat中收到错误。

04-02 11:31:08.095: E/AndroidRuntime(674): FATAL EXCEPTION: main
04-02 11:31:08.095: E/AndroidRuntime(674): android.database.sqlite.SQLiteException: near "TABLEstudent": syntax error (code 1): , while compiling: CREATE TABLEstudent(nameTEXT,cclassTEXT);
04-02 11:31:08.095: E/AndroidRuntime(674): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:882)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1663)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1594)
04-02 11:31:08.095: E/AndroidRuntime(674):  at com.example.student_data.AndroidDbHelper.onCreate(AndroidDbHelper.java:25)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:252)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
04-02 11:31:08.095: E/AndroidRuntime(674):  at com.example.student_data.Student_Data.insertData(Student_Data.java:41)
04-02 11:31:08.095: E/AndroidRuntime(674):  at com.example.student_data.Student_Data.onClick(Student_Data.java:36)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.view.View.performClick(View.java:4084)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.view.View$PerformClick.run(View.java:16966)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.os.Handler.handleCallback(Handler.java:615)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.os.Looper.loop(Looper.java:137)
04-02 11:31:08.095: E/AndroidRuntime(674):  at android.app.ActivityThread.main(ActivityThread.java:4745)
04-02 11:31:08.095: E/AndroidRuntime(674):  at java.lang.reflect.Method.invokeNative(Native Method)
04-02 11:31:08.095: E/AndroidRuntime(674):  at java.lang.reflect.Method.invoke(Method.java:511)
04-02 11:31:08.095: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
04-02 11:31:08.095: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-02 11:31:08.095: E/AndroidRuntime(674):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_student__data);

    studentName= (EditText) findViewById(R.id.editText1);
    StuClass= (EditText) findViewById(R.id.editText2);        
    b1=(Button) findViewById(R.id.button1);                
    b1.setOnClickListener(this);
}

@Override
public void onClick(View v) 
{
    // TODO Auto-generated method stub
    NameStudent = studentName.getText().toString();
    ClassStudent = StuClass.getText().toString();        
    insertData(NameStudent, ClassStudent);
}

你在OnCreate Time获取String将始终为你提供空字符串。将它写入onClick方法将为您提供完美的输出。

String CreateTable = "CREATE TABLE" + TABLE_NAME + "(" + COLUMN_NAME + "TEXT," + COLUMN_CLASS + "TEXT" + ");";

将此行替换为此

String CreateTable = "CREATE TABLE " + TABLE_NAME + " ( " + COLUMN_NAME + " TEXT, " + COLUMN_CLASS + " TEXT" + ");";

Answer 2

在onCreate()方法中，您的EditTexts为空，因此我建议您将两行移动到onClick（）方法。

按如下方式更改onClick()方法，

@Override
public void onClick(View v) 
{
    // TODO Auto-generated method stub
     NameStudent = studentName.getText().toString();  //move these lines from onCreate() method to here
     ClassStudent = StuClass.getText().toString(); 
     insertData(NameStudent, ClassStudent);
}

Answer 3

你的SQL错了。

的结果

String CreateTable = "CREATE TABLE" + TABLE_NAME + "(" + COLUMN_NAME + "TEXT," + COLUMN_CLASS + "TEXT" + ");";

是

CREATE TABLEStudentData(nameTEXT, cclassTEXT)

您需要添加空格

String CreateTable = "CREATE TABLE " + TABLE_NAME + " ( " + COLUMN_NAME + " TEXT, " + COLUMN_CLASS + " TEXT " + " );";

如何将编辑文本中的数据插入sqlite数据库？

3 个答案: