Question

我正在尝试从http://www.codebind.com/android-tutorials-and-examples/android-sqlite-tutorial-example/学习Android SQLite 但是在我的android工作室中运行代码时，我不断得到一个读取的红色无法解析符号操作设置广告无法解析菜单。这是我的activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Name"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Surname"
        android:id="@+id/textView2"
        android:layout_below="@+id/editText_name"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Marks"
        android:id="@+id/textView3"
        android:layout_below="@+id/editText_surname"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText_name"
        android:layout_alignTop="@+id/textView"
        android:layout_toRightOf="@+id/textView"
        android:layout_toEndOf="@+id/textView" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText_surname"
        android:layout_alignTop="@+id/textView2"
        android:layout_toRightOf="@+id/textView2"
        android:layout_toEndOf="@+id/textView2" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText_Marks"
        android:layout_below="@+id/editText_surname"
        android:layout_toRightOf="@+id/textView3"
        android:layout_toEndOf="@+id/textView3" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Add Data"
        android:id="@+id/button_add"
        android:layout_below="@+id/editText_Marks"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="76dp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="View All"
        android:id="@+id/button_viewAll"
        android:layout_above="@+id/button_update"
        android:layout_centerHorizontal="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Update"
        android:id="@+id/button_update"
        android:layout_below="@+id/button_add"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Delete"
        android:id="@+id/button_delete"
        android:layout_centerVertical="true"
        android:layout_below="@+id/button_viewAll"
        android:layout_alignLeft="@+id/button_viewAll"
        android:layout_alignStart="@+id/button_viewAll" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="id"
        android:id="@+id/textView_id"
        android:layout_below="@+id/editText_Marks"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editText_id"
        android:layout_alignTop="@+id/textView_id"
        android:layout_toRightOf="@+id/textView3"
        android:layout_toEndOf="@+id/textView3" />

</RelativeLayout>

这是MainActivity.java

package com.example.user.sqliteapp;
import com.example.user.sqliteapp.R;
import android.app.AlertDialog;
import android.database.Cursor;
import android.support.v7.app.ActionBarActivity;
import android.widget.TextView;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.text.Editable;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;

import android.widget.EditText;
import android.widget.Toast;
import android.content.Context;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;

import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;

import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

import android.support.v7.app.AppCompatActivity;


import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.appindexing.Thing;
import com.google.android.gms.common.api.GoogleApiClient;

import java.text.NumberFormat;

import static com.example.user.sqliteapp.R.*;
import static com.example.user.sqliteapp.R.id.*;
import static com.example.user.sqliteapp.R.id.textView;


public class MainActivity extends AppCompatActivity {

    Databasehelper myDb;
    EditText editName,editSurname,editMarks ,editTextId;
    Button btnAddData;
    Button btnviewAll;
    Button btnDelete;

    Button btnviewUpdate;
    private GoogleApiClient client;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(layout.activity_main);
        myDb = new Databasehelper(this);

        editName = (EditText) findViewById(id.editText_name);
        editSurname = (EditText) findViewById(id.editText_surname);
        editMarks = (EditText) findViewById(id.editText_Marks);
        editTextId = (EditText) findViewById(id.editText_id);
        btnAddData = (Button) findViewById(id.button_add);
        btnviewAll = (Button) findViewById(id.button_viewAll);
        btnviewUpdate = (Button) findViewById(id.button_update);
        btnDelete = (Button) findViewById(id.button_delete);
        AddData();
        viewAll();
        UpdateData();
        DeleteData();
        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
    }

    public void DeleteData() {
        btnDelete.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Integer deletedRows = myDb.deleteData(editTextId.getText().toString());
                        if (deletedRows > 0)
                            Toast.makeText(MainActivity.this, "Data Deleted", Toast.LENGTH_LONG).show();
                        else
                            Toast.makeText(MainActivity.this, "Data not Deleted", Toast.LENGTH_LONG).show();
                    }
                }
        );
    }

    public void UpdateData() {
        btnviewUpdate.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        boolean isUpdate = myDb.updateData(editTextId.getText().toString(),
                                editName.getText().toString(),
                                editSurname.getText().toString(), editMarks.getText().toString());
                        if (isUpdate == true)
                            Toast.makeText(MainActivity.this, "Data Update", Toast.LENGTH_LONG).show();
                        else
                            Toast.makeText(MainActivity.this, "Data not Updated", Toast.LENGTH_LONG).show();
                    }
                }
        );
    }

    public void AddData() {
        btnAddData.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        boolean isInserted = myDb.insertData(editName.getText().toString(),
                                editSurname.getText().toString(),
                                editMarks.getText().toString());
                        if (isInserted == true)
                            Toast.makeText(MainActivity.this, "Data Inserted", Toast.LENGTH_LONG).show();
                        else
                            Toast.makeText(MainActivity.this, "Data not Inserted", Toast.LENGTH_LONG).show();
                    }
                }
        );
    }

    public void viewAll() {
        btnviewAll.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Cursor res = myDb.getAllData();
                        if (res.getCount() == 0) {
                            // show message
                            showMessage("Error", "Nothing found");
                            return;
                        }

                        StringBuffer buffer = new StringBuffer();
                        while (res.moveToNext()) {
                            buffer.append("Id :" + res.getString(0) + "\n");
                            buffer.append("Name :" + res.getString(1) + "\n");
                            buffer.append("Surname :" + res.getString(2) + "\n");
                            buffer.append("Marks :" + res.getString(3) + "\n\n");
                        }

                        // Show all data
                        showMessage("Data", buffer.toString());
                    }
                }
        );
    }

    public void showMessage(String title, String Message) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setCancelable(true);
        builder.setTitle(title);
        builder.setMessage(Message);
        builder.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.menu_main, 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.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);

    }

    /**
     * ATTENTION: This was auto-generated to implement the App Indexing API.
     * See https://g.co/AppIndexing/AndroidStudio for more information.
     */
    public Action getIndexApiAction() {
        Thing object = new Thing.Builder()
                .setName("Main Page") // TODO: Define a title for the content shown.
                // TODO: Make sure this auto-generated URL is correct.
                .setUrl(Uri.parse("http://[ENTER-YOUR-URL-HERE]"))
                .build();
        return new Action.Builder(Action.TYPE_VIEW)
                .setObject(object)
                .setActionStatus(Action.STATUS_TYPE_COMPLETED)
                .build();
    }

    @Override
    public void onStart() {
        super.onStart();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client.connect();
        AppIndex.AppIndexApi.start(client, getIndexApiAction());
    }

    @Override
    public void onStop() {
        super.onStop();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        AppIndex.AppIndexApi.end(client, getIndexApiAction());
        client.disconnect();
    }
}

和Databasehelper.java P

ackage com.example.user.sqliteapp;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;


/**
 * Created by User on 22-Feb-17.
 */
public class Databasehelper extends SQLiteOpenHelper {
    public static final String DATABASE_NAME = "Student.db";
    public static final String TABLE_NAME = "student_table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "NAME";
    public static final String COL_3 = "SURNAME";
    public static final String COL_4 = "MARKS";

    public Databasehelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + TABLE_NAME +" (ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,SURNAME TEXT,MARKS INTEGER)");
    }

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

    public boolean insertData(String name,String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        long result = db.insert(TABLE_NAME,null ,contentValues);
        if(result == -1)
            return false;
        else
            return true;
    }

    public Cursor getAllData() {
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor res = db.rawQuery("select * from "+TABLE_NAME,null);
        return res;
    }

    public boolean updateData(String id,String name,String surname,String marks) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_1,id);
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,surname);
        contentValues.put(COL_4,marks);
        db.update(TABLE_NAME, contentValues, "ID = ?",new String[] { id });
        return true;
    }

    public Integer deleteData (String id) {
        SQLiteDatabase db = this.getWritableDatabase();
        return db.delete(TABLE_NAME, "ID = ?",new String[] {id});
    }
}

Answer 1

您可以尝试相同的原因：

您也可以在Android Studio中尝试此操作。转到工具 - ＆gt; Android - ＆gt;单击“使用gradle同步项目文件”。

无法解析符号操作设置

1 个答案: