用adb shell无法显示数据库中的内容，本人初学者
public class MainActivity extends AppCompatActivity {
private MyDatabaseHelper dbHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 2);
Button createDatabase = (Button)findViewById(R.id.create_database);
Button addData = (Button)findViewById(R.id.add_data);
createDatabase.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
dbHelper.getWritableDatabase();
}
});
addData.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("name", "the da vinci code");
values.put("author", "Dan Brown");
values.put("pages", 454);
values.put("price", 16.96);
db.insert("Book", null, values);
values.clear();
values.put("name", "the lost symbol");
values.put("author", "Dan Brown");
values.put("pages", 510);
values.put("price", 19.95);
db.insert("Book", null, values);
Log.d("MyDatabaseHelper", "insert succeed");
}
});
}
}
public class MyDatabaseHelper extends SQLiteOpenHelper {
public static final String CREATE_BOOK = "create table Book ("
+ "id integer primary key autoincrement, "
+ "author text, "
+ "price real, "
+ "pages integer, "
+ "name text)";
public static final String CREATE_CATEGORY = "create table Category ("
+ "id integer primary key autoincrement, "
+ "category_name text, "
+ "category_code integer)";
private Context mContext;
public MyDatabaseHelper(Context context, String name, CursorFactory factory, int version) {
super(context, name, factory, version);
Log.d("MyDatabaseHelper", "执行MyDatabaseHelper构造方法");
mContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.d("MyDatabaseHelper", "执行onCreate方法");
db.execSQL(CREATE_BOOK);
db.execSQL(CREATE_CATEGORY);
Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.d("MyDatabaseHelper", "执行onUpgrade方法");
db.execSQL("drop table if exists Book");
db.execSQL("drop table if exists Category");
onCreate(db);
}
}