Question

我正在尝试在Android应用程序中创建和维护数据库＆＃34;代码看起来很好，但点击提交按钮应用程序已经崩溃，这是不期望的;

layout.xml文件

    <?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:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.example.firstproject.saveinfoindatabase.MainActivity">


        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/editText"
            android:layout_alignParentTop="true"
            android:layout_centerHorizontal="true"
            android:hint="name"/>

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/editText2"
            android:layout_below="@+id/editText"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="80dp"
            android:hint="phone"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="submit"
            android:id="@+id/button"
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:layout_marginBottom="93dp"/>


    </RelativeLayout>

mainActivity.java文件

     public class MainActivity extends AppCompatActivity {

            EditText  name,phone;


            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                name=(EditText) findViewById(R.id.editText);
                phone=(EditText) findViewById(R.id.editText2);
                Button button=(Button)findViewById(R.id.button);

                button.setOnClickListener(new View.OnClickListener() {

                    @Override
                    public void onClick(View v) {

                        String getNmae = name.getText().toString();
                        String getPhone = phone.getText().toString();

                        DataBaseOpreation objOFDataBaseOpreation = new DataBaseOpreation(getBaseContext());

                        objOFDataBaseOpreation.insertInfo(getNmae, getPhone);

                        Toast.makeText(getBaseContext(), "dataInserted", Toast.LENGTH_LONG).show();

                        objOFDataBaseOpreation.close();
                    }
                });

            }


        }

DataBaseOpreation.java文件（此文件维护数据库）

     public class DataBaseOpreation extends SQLiteOpenHelper{
            public static final String DATA_BASE_NAME="mydatabase";
            public static final String TABLE_NAME="save.info";

            DataBaseOpreation(Context context){
                super(context,DATA_BASE_NAME,null,1);

            }


            @Override
            public void onCreate(SQLiteDatabase db) {

                db.execSQL(
                        "create table save.info " +
                                "(id integer primary key, name text, phone text)"
                );
            }

            @Override
            public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

                db.execSQL("DROP TABLE IF EXISTS save.info");
                onCreate(db);

            }
            public void insertInfo(String name,String phone){

                SQLiteDatabase db=this.getWritableDatabase();

                ContentValues contentValues=new ContentValues();

                contentValues.put("NAME",name);
                contentValues.put("PHONE", phone);

                db.insert(TABLE_NAME, null, contentValues);

            }
            public Cursor getData(){

                SQLiteDatabase db = this.getReadableDatabase();

                Cursor res =  db.rawQuery("select * from save.info",null);

                return res;

            }
        }

manifest.xml文件

<?xml version="1.0" encoding="utf-8"?>
<manifest package="com.example.firstproject.saveinfoindatabase"
          xmlns:android="http://schemas.android.com/apk/res/android">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>

    </application>

</manifest>

Answer 1

SQLiteOpenHelper是A helper class to manage database creation and version management. ，它通常与contentprovider一起使用来设置数据库表等。所以你有一半的解决方案。我建议您使用one of the code generation tools实现contentprovider，为您完成繁琐的工作。许多其他contententprovider生成器可用，如果它不适合您的需求。

不幸的是，我的申请已停止

1 个答案: