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android - 从 onClickListener 检索图像(保存在 sqlite 中)

转载 作者：太空狗 更新时间：2023-10-29 13:15:34 26 4
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我创建了一个图书应用程序，您可以在其中保存来自互联网 (googleBooksAPI) 的图书。BookData(标题、作者、图像)将保存在 SQLite 数据库中。您可以在 ListView 中查看书籍。如果你点击一行(一本书)，所有的书本数据都会显示在一个新的 Activity 中(bookInfoActivity)我的问题是，我不知道如何将我单击的行的图像传递给 bookinfoactivity。

我试过如下，但我和你都知道它只会传递第一行的图像。

BookInfoActivity

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_book_info);
    bookDBHelper = new BookDBHelper(this);
    Typeface myTypeface = Typeface.createFromAsset(getAssets(), "Lobster.ttf");
    TextView myTextView = (TextView) findViewById(R.id.yourbookinfo);
    myTextView.setTypeface(myTypeface);

    imageView = (ImageView) findViewById(R.id.passed_bookimage);
    btn_update = (Button) findViewById(R.id.button_update);
    btn_delete_book = (Button) findViewById(R.id.btn_delete_book);

    Intent intent = getIntent();
    String secret_editText_titel = intent.getStringExtra(BookDataListActivity.EXTRA_MSG0);

    cursor2.moveToFirst();

    int rows = cursor2.getCount();

    for(int i=0; i < rows; i++ ){
        String booktitle = cursor2.getString(1);
        byte[] blob= cursor2.getBlob(0);
        Bitmap bookimage = BitmapFactory.decodeByteArray(blob, 0, blob.length);
        imageView.setImageBitmap(bookimage);
        Toast.makeText(this, "here is your image", Toast.LENGTH_SHORT).show();

    if(secret_editText_titel == booktitle){

    }else{
        cursor2.moveToNext();
    }
    }

    /*bookDBHelper = new BookDBHelper(getApplicationContext());
    sqLiteDatabaseBooks = bookDBHelper.getReadableDatabase();
    cursor2 = bookDBHelper.getInformations(sqLiteDatabaseBooks);
    if (cursor2.moveToPrevious()) {
        {
            String se
            byte[] blob= cursor2.getBlob(0);
            Bitmap bookimage = BitmapFactory.decodeByteArray(blob, 0, blob.length);
            imageView.setImageBitmap(bookimage);
            Toast.makeText(this, "here is your image", Toast.LENGTH_SHORT).show();

        }
    }*/

    String secret_title = intent.getStringExtra(BookDataListActivity.EXTRA_MSG1);
    Secret_editText_title = (EditText) findViewById(R.id.secret_edittext_title);
    Secret_editText_title.setText(secret_title);

    //defaultImage = (ImageView) findViewById(R.id.defaultImage);
    /*Bitmap book_image = intent.????????(BookDataListActivity.EXTRA_MSG0);
    passedbookimage = (ImageView) findViewById(R.id.passed_bookimage);
    passedbookimage.setImageBitmap(book_image);
*/
    String book_title = intent.getStringExtra(BookDataListActivity.EXTRA_MSG1);
    passedbooktitle = (EditText) findViewById(R.id.passed_booktitle);
    passedbooktitle.setText(book_title);

    String book_author = intent.getStringExtra(BookDataListActivity.EXTRA_MSG2);
    passedbookauthor = (EditText) findViewById(R.id.passed_bookauthor);
    passedbookauthor.setText(book_author);

    String book_date = intent.getStringExtra(BookDataListActivity.EXTRA_MSG3);
    passedbookdate = (EditText) findViewById(R.id.passed_bookdate);
    passedbookdate.setText(book_date);

    String book_rating = intent.getStringExtra(BookDataListActivity.EXTRA_MSG4);
    passedbookrating = (EditText) findViewById(R.id.passed_bookrating);
    passedbookrating.setText(book_rating);

    String book_shelf = intent.getStringExtra(BookDataListActivity.EXTRA_MSG5);
    passedbookshelf = (EditText) findViewById(R.id.passed_bookshelf);
    passedbookshelf.setText(book_shelf);

    DeleteData();
}

*BookDBHelper

public class BookDBHelper extends SQLiteOpenHelper{

public SQLiteDatabase sqLiteDatabase;

private static final String DATABASE_BOOKS_NAME = "BookINFO.DB";
private static final int DATABASE_BOOKS_VERS = 2;
private static final String CREATE_QUERY_BOOKS =
        "CREATE TABLE "
                + BookContent.NewBookInfo.TABLE_NAME_BOOKS
                +"("
                + BookContent.NewBookInfo.BOOK_IMAGE +" BLOB NOT NULL, "
                + BookContent.NewBookInfo.BOOK_TITLE+" TEXT, "
                + BookContent.NewBookInfo.BOOK_AUTHOR+" TEXT, "
                + BookContent.NewBookInfo.BOOK_DATE+" TEXT, "
                + BookContent.NewBookInfo.BOOK_RATING+" TEXT, "
                + BookContent.NewBookInfo.BOOK_SHELF+" TEXT);";


public BookDBHelper(Context context){
    super(context, DATABASE_BOOKS_NAME, null, DATABASE_BOOKS_VERS);
    Log.e("DATABASE OPERATIONS", " DATABASE CREATED");
}

@Override
public void onCreate(SQLiteDatabase bookdb) {

    bookdb.execSQL(CREATE_QUERY_BOOKS);
    Log.e("DATABASE OPERATIONS", " DATABASE CREATED");
}

@Override
public void onUpgrade(SQLiteDatabase bookdb, int oldVersion, int newVersion) {
    bookdb.execSQL(" DROP TABLE IS EXISTS " + BookContent.NewBookInfo.TABLE_NAME_BOOKS);
    onCreate(bookdb);
}

public void addInformations(byte[] image, String booktitle, String bookauthor, String bookdate, String bookrating, String bookshelf, SQLiteDatabase bookdb)
{

    ContentValues contentValues = new ContentValues();
    contentValues.put(BookContent.NewBookInfo.BOOK_IMAGE, image);
    contentValues.put(BookContent.NewBookInfo.BOOK_TITLE, booktitle);
    contentValues.put(BookContent.NewBookInfo.BOOK_AUTHOR, bookauthor);
    contentValues.put(BookContent.NewBookInfo.BOOK_DATE, bookdate);
    contentValues.put(BookContent.NewBookInfo.BOOK_RATING, bookrating);
    contentValues.put(BookContent.NewBookInfo.BOOK_SHELF, bookshelf);

    bookdb.insert(BookContent.NewBookInfo.TABLE_NAME_BOOKS, null, contentValues);
    Log.e("DATABASE OPERATIONS", "ON ROW INSERTED");
}

public void addOwnBookInformations(String booktitle, String bookauthor, String bookdate, String bookrating, String bookshelf, SQLiteDatabase bookdb)
{

    ContentValues contentValues = new ContentValues();
    contentValues.put(BookContent.NewBookInfo.BOOK_TITLE, booktitle);
    contentValues.put(BookContent.NewBookInfo.BOOK_AUTHOR, bookauthor);
    contentValues.put(BookContent.NewBookInfo.BOOK_DATE, bookdate);
    contentValues.put(BookContent.NewBookInfo.BOOK_RATING, bookrating);
    contentValues.put(BookContent.NewBookInfo.BOOK_SHELF, bookshelf);

    bookdb.insert(BookContent.NewBookInfo.TABLE_NAME_BOOKS, null, contentValues);
    Log.e("DATABASE OPERATIONS", "ON ROW INSERTED");
}

public Cursor getInformations(SQLiteDatabase bookdb){
    Cursor cursor2;
        String[] projections = {
                BookContent.NewBookInfo.BOOK_IMAGE,
                BookContent.NewBookInfo.BOOK_TITLE,
                BookContent.NewBookInfo.BOOK_AUTHOR,
                BookContent.NewBookInfo.BOOK_DATE,
                BookContent.NewBookInfo.BOOK_RATING,
                BookContent.NewBookInfo.BOOK_SHELF};
    cursor2 = bookdb.query(BookContent.NewBookInfo.TABLE_NAME_BOOKS, projections,null, null, null, null, null);
    return cursor2;
}

BookDataListActivity

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

    Typeface myTypeface = Typeface.createFromAsset(getAssets(), "Lobster.ttf");

    TextView myTextView = (TextView) findViewById(R.id.text_yourbooks);
    myTextView.setTypeface(myTypeface);

    btn_home = (Button) findViewById(R.id.btn_home);

    booklistView = (ListView) findViewById(R.id.book_list_view);
    inputSearch = (EditText) findViewById(R.id.search_bar);
    imageView = (ImageView) findViewById(R.id.book_image);

    bookListDataAdapter = new BookListDataAdapter(getApplicationContext(), R.layout.row_book_layout);
    booklistView.setAdapter(bookListDataAdapter);


    //onItemClickListener
    booklistView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            Intent intent = new Intent(getApplicationContext(), BookInfoActivity.class);

            /*imageView = (ImageView) findViewById(R.id.book_image);
            byte[] book_image = cursor2.getBlob(cursor2.getColumnIndex(BookContent.NewBookInfo.BOOK_IMAGE));
            imageView.setImageBitmap(BitmapFactory.decodeByteArray(book_image,0,book_image.length));
            //intent.putExtra(EXTRA_MSG0, book_image);
*/

            editTextBooktitle = (TextView) view.findViewById(R.id.text_book_title);
            String book_title = editTextBooktitle.getText().toString();
            intent.putExtra(EXTRA_MSG1, book_title);

            editTextBookauthor = (TextView) view.findViewById(R.id.text_book_author);
            String bookauthor = editTextBookauthor.getText().toString();
            intent.putExtra(EXTRA_MSG2, bookauthor);

            editTextBookdate = (TextView) view.findViewById(R.id.text_book_date);
            String bookdate = editTextBookdate.getText().toString();
            intent.putExtra(EXTRA_MSG3, bookdate);

            editTextBookrating = (TextView) view.findViewById(R.id.text_book_rating);
            String bookrating = editTextBookrating.getText().toString();
            intent.putExtra(EXTRA_MSG4, bookrating);

            editTextBookshelf = (TextView) view.findViewById(R.id.text_book_shelf);
            String bookshelf = editTextBookshelf.getText().toString();
            intent.putExtra(EXTRA_MSG5, bookshelf);

            startActivity(intent);

            onResume();

        }

    });


    inputSearch.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            bookListDataAdapter.getFilter().filter(s);
        }

        @Override
        public void afterTextChanged(Editable s) {

        }
    });

    bookDBHelper = new BookDBHelper(getApplicationContext());
    sqLiteDatabaseBooks = bookDBHelper.getReadableDatabase();
    cursor2 = bookDBHelper.getInformations(sqLiteDatabaseBooks);
    if (cursor2.moveToFirst()) {
        do {
            String booktitle, bookauthor, bookdate, bookrating, bookshelf;
            Bitmap bookimage;

            byte[] blob= cursor2.getBlob(0);
            bookimage = BitmapFactory.decodeByteArray(blob,0,blob.length);
            booktitle = cursor2.getString(1);
            bookauthor = cursor2.getString(2);
            bookdate = cursor2.getString(3);
            bookrating = cursor2.getString(4);
            bookshelf = cursor2.getString(5);

            BookDataProvider bookDataProvider = new BookDataProvider(bookimage, booktitle, bookauthor, bookdate, bookrating, bookshelf);
            bookListDataAdapter.add(bookDataProvider);

        } while (cursor2.moveToNext());
    }
    backtoMainView();
}

public void backtoMainView(){
    btn_home.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(), MainActivity.class);
            startActivity(intent);
        }
    });
}
@Override
public void onResume(){
    super.onResume();
    bookListDataAdapter.notifyDataSetChanged();

}
}

LOGcat*

    Process: com.kasutwentyseven.gui4selfshelf, PID: 20482
                                                                               java.lang.RuntimeException: Unable to start activity ComponentInfo{com.kasutwentyseven.gui4selfshelf/com.kasutwentyseven.gui4selfshelf.Books.BookInfoActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor android.database.sqlite.SQLiteDatabase.query(java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String)' on a null object reference
                                                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2357)
                                                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2419)
                                                                                   at android.app.ActivityThread.access$900(ActivityThread.java:154)
                                                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                   at android.os.Looper.loop(Looper.java:135)
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:5291)
                                                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                                                   at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)
                                                                                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor android.database.sqlite.SQLiteDatabase.query(java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String)' on a null object reference
                                                                                   at com.kasutwentyseven.gui4selfshelf.Books.BookDBHelper.getInformations(BookDBHelper.java:85)
                                                                                   at com.kasutwentyseven.gui4selfshelf.Books.BookInfoActivity.onCreate(BookInfoActivity.java:60)
                                                                                   at android.app.Activity.performCreate(Activity.java:5990)
                                                                                   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                                                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2310)
                                                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2419) 
                                                                                   at android.app.ActivityThread.access$900(ActivityThread.java:154) 
                                                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321) 
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                   at android.os.Looper.loop(Looper.java:135) 
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:5291) 
                                                                                   at java.lang.reflect.Method.invoke(Native Method) 
                                                                                   at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904) 
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699) 

最佳答案

还有很多事情要做，解释整个 SQLite 实现超出了这里的框架。首先，您必须为您的数据库中的每本书实现一个唯一的 ID。然后你必须通过 Intent 将这个 ID 传递到你的下一个 Activity 中，在那里你显示图书信息:

从 listView Activity 传递 id:

Intent myIntent = new Intent(YourListViewActivity.this, yourBookActivity.class);
myIntent.putExtra("bookid", id_value);
startActivity(myIntent);

在您的图书 Activity 中获取它:

Intent mIntent = getIntent();
int idValue= mIntent.getIntExtra("bookid", 0);

如果你掌握了这一切，那么就像这样很容易:

    //set the cursor to the first row
    cursor2.moveToFirst();

    //get the number of rows
    int rows = cursor2.getCount();

    //loop through the cursor
    for(int i=0;i<rows;i++){

       //get the id
       int id = cursor2.getInt(0);
       byte[] blob= cursor2.getBlob(1);
                Bitmap bookimage = BitmapFactory.decodeByteArray(blob, 0, blob.length);
                imageView.setImageBitmap(bookimage);
                Toast.makeText(this, "here is your image", Toast.LENGTH_SHORT).show();

    if(idValue==id){

      //stop cursor here because You get what You wanted
    }else{

    cursor2.moveToNext();

    }

  }

但这只是一个可能的例子，还有其他方法。您应该阅读如何根据您的 Intent 构建正确的数据库:

http://examples.javacodegeeks.com/android/core/database/android-database-example/

关于android - 从 onClickListener 检索图像(保存在 sqlite 中)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35060606/

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