我想打一個應用程序,有報價和作家,我從SQLite的預填充數據庫中獲取的列表如何風格我的TextView和按鈕圖像內的ListView
所以在左邊,我有2個textviews(1爲報價,另一個爲作者)
和在右邊,這是一個圖像按鈕,每次我點擊心臟圖像從灰色到紅色,如果再次點擊,則會變成灰色
我已經使用2個textview和另一個xml的1個圖像按鈕來填充我的listview和數據庫。但我不知道如何風格的字體和改變,只要其點擊
這裏的形象是我的代碼
DatabaseOpenHelper.java
public class DatabaseOpenHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "mqn.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_NAME = "quote";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_QUOTES = "quotesText";
public static final String COLUMN_AUTHOR= "author";
public static final String COLUMN_FAV = "fav";
private SQLiteDatabase database;
private final Context context;
// database path
private static String DATABASE_PATH;
/** constructor */
public DatabaseOpenHelper(Context ctx) {
super(ctx, DATABASE_NAME, null, DATABASE_VERSION);
this.context = ctx;
DATABASE_PATH = context.getFilesDir().getParentFile().getPath()
+ "/databases/";
}
/**
* Creates a empty database on the system and rewrites it with your own
* database.
* */
public void create() throws IOException {
boolean check = checkDataBase();
SQLiteDatabase db_Read = null;
// Creates empty database default system path
db_Read = this.getWritableDatabase();
db_Read.close();
try {
if (!check) {
copyDataBase();
}
} catch (IOException e) {
throw new Error("Error copying database");
}
}
/**
* Check if the database already exist to avoid re-copying the file each
* time you open the application.
*
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
// database does't exist yet.
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created
* empty database in the system folder, from where it can be accessed and
* handled. This is done by transfering bytestream.
* */
private void copyDataBase() throws IOException {
// Open your local db as the input stream
InputStream myInput = context.getAssets().open(DATABASE_NAME);
// Path to the just created empty db
String outFileName = DATABASE_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
/** open the database */
public void open() throws SQLException {
String myPath = DATABASE_PATH + DATABASE_NAME;
database = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
/** close the database */
@Override
public synchronized void close() {
if (database != null)
database.close();
super.close();
}
// insert a user into the database
public long insertUser(String quotesText, String author, String fav) {
ContentValues initialValues = new ContentValues();
initialValues.put(COLUMN_QUOTES, quotesText);
initialValues.put(COLUMN_AUTHOR, author);
initialValues.put(COLUMN_FAV, fav);
return database.insert(TABLE_NAME, null, initialValues);
}
// updates a user
public boolean updateUser(long rowId, String quotesText, String author,
String fav) {
ContentValues args = new ContentValues();
args.put(COLUMN_QUOTES, quotesText);
args.put(COLUMN_AUTHOR, author);
args.put(COLUMN_FAV, fav);
return database.update(TABLE_NAME, args, COLUMN_ID + "=" + rowId, null) > 0;
}
// retrieves a particular user
public Cursor getUser(long rowId) throws SQLException {
Cursor mCursor = database.query(true, TABLE_NAME, new String[] {
COLUMN_ID, COLUMN_QUOTES, COLUMN_AUTHOR, COLUMN_FAV },
COLUMN_ID + " = " + rowId, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
// delete a particular user
public boolean deleteContact(long rowId) {
return database.delete(TABLE_NAME, COLUMN_ID + "=" + rowId, null) > 0;
}
// retrieves all users
public Cursor getAllUsers() {
return database.query(TABLE_NAME, new String[] { COLUMN_ID,
COLUMN_QUOTES, COLUMN_AUTHOR, COLUMN_FAV }, null, null,
null, null, null);
}
@Override
public void onCreate(SQLiteDatabase arg0) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
QuotesActivity.java
public class QuotesActivity extends AppCompatActivity {
TextView title;
Typeface myFont;
ListView quotesList;
ListView favLV;
DatabaseOpenHelper myDbHelper;
DatabaseAccess databaseAccess;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_quotes);
myDbHelper = new DatabaseOpenHelper(this);
try {
// check if database exists in app path, if not copy it from assets
myDbHelper.create();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
// open the database
myDbHelper.open();
myDbHelper.getWritableDatabase();
} catch (SQLException sqle) {
throw sqle;
}
populateListView();
Toolbar toolbar = (Toolbar) findViewById(R.id.tool_bar);
toolbar.setNavigationIcon(R.drawable.back_button);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowTitleEnabled(false);
title = (TextView) findViewById(R.id.titleQuote);
myFont = Typeface.createFromAsset(getAssets(), "Montserrat-Bold.otf");
title.setTypeface(myFont);
title.setTextSize(20);
title.setTextColor(Color.rgb(240, 239, 223));
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
private void populateListView() {
Cursor cursor = myDbHelper.getAllUsers();
String[] from = new String[] {myDbHelper.COLUMN_QUOTES, myDbHelper.COLUMN_AUTHOR};
int[] to = new int[] {R.id.quoteLV, R.id.authorLV};
SimpleCursorAdapter myCursorAdapter;
myCursorAdapter = new SimpleCursorAdapter(getBaseContext(), R.layout.quotes_listview, cursor, from, to,0);
quotesList = (ListView) findViewById(R.id.quotesList);
quotesList.setAdapter(myCursorAdapter);
}
}
Content_quotes.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="hendrasetiawan.mqn.QuotesActivity"
tools:showIn="@layout/activity_quotes">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true">
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/quotesList"
android:layout_gravity="right"
android:layout_weight="1" />
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/favList"
android:layout_weight="6" />
</LinearLayout>
</LinearLayout>
</LinearLayout>
quotes_listview.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Text"
android:id="@+id/quoteLV"
android:textSize="20dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Text"
android:id="@+id/authorLV"
android:textSize="20dp"/>
</LinearLayout>
每次我嘗試設置字體的大小/改變行情的活動 的字體我總是在空對象引用的Android得到錯誤
編輯帖子
我logcat的
(注=我quoteLV和authorLV現在文本1和文本) ,我嘗試把text1.setTextSize(50); populateView()
03-23 17:23:30.621 26550-26550 /? I/art:延遲啓用-Xcheck:jni 03-23 17:23:30.659 26550-26550/hendrasetiawan.mqn W/System:ClassLoader引用的未知路徑:/data/app/hendrasetiawan.mqn-1/lib/arm 03-23 17:23:30.953 26550-26590/hendrasetiawan.mqn D/OpenGLRenderer:使用EGL_SWAP_BEHAVIOR_PRESERVED:true 03-23 17:23:30.996 26550-26590/hendrasetiawan.mqn我/ Adreno-EGL :: QUALCOMM構建: 10/21/15,369a2ea,I96aee987eb 03-23 17:23:30.999 26550-26590/hendrasetiawan.mqn I/OpenGLRenderer:初始化的EGL,版本1.4 03-23 17:23:32.201 26550-26550/hendrasetiawan.mqn I/SQLiteAssetHelper:成功打開數據庫mqn.db 03-23 17:23:32.205 26550-26550/hendrasetiawan.mqn I/SQLiteAssetHelper:成功打開數據庫mqn.db 03-23 17:23:32.216 26550-26550/hendrasetiawan .mqn D/AndroidRuntime:關閉關閉VM 03-23 17:23:32.217 26550-26550/hendrasetiawan.mqn E/AndroidRuntime:致命異常:主要 進程:hendrasetiawan.mqn,PID:26550 java.lang。RuntimeException:無法啓動活動ComponentInfo {hendrasetiawan.mqn/hendrasetiawan.mqn.QuotesActivity}:java.lang.NullPointerException:嘗試在空對象引用 處調用虛擬方法'void android.widget.TextView.setTextSize(float)'at android.app.AudioThread.performanceLaunchActivity(ActivityThread.java:2416) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android.app.ActivityThread.-wrap11(ActivityThread.java) at android.app .ActivityThread $ H.handleMessage(ActivityThread.java:1344) 在android.os.Handler.dispatchMessage(Handler.java:102) 在android.os.Looper.loop(Looper.java:148) 的機器人。 app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:726) 在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 引起:java.lang.NullPointerException:試圖調用虛函數'void android.widget.TextView.setTextSize(float)'null在android.app.Activity.performCreate(Activity.java:6251)上的對象引用 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) at android .app.ActivityThread.-wrap11(ActivityThread.java) 在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1344) 在android.os.Handler.dispatchMessage(Handler.java:102) 的機器人。 os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:726) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 03-23 17:28: 32.266 26550-26550/hendrasetiawan.mqn I /過程:發送信號。 PID:26550 SIG:9
新的編輯POST
content_quotes.xml
這裏面我只有1的ListView
inside_listview.xml
這裏內幕我有2個textViews和1 ButtonImage
行情活動
該Java,在的setContentView content_quotes.xml 所以,當我風格content_quotes一切。XML,我可以很容易地做到這一點
而現在,我獲取所有從數據庫 引號和作者到2個textviews(這是inside_listview.xml)
,每次我試圖樣式它的2 textviews,我總是得到一個錯誤 是因爲它來自另一個XML?
ü可以發佈您的logcat的想法? – Raghavendra
我已經可以用數據庫填充列表視圖,它的工作原理 但是當我嘗試設置textview(quoteLV.setTextSize(50);)的樣式時,它會引發錯誤。 啊WAIT2 –
可能是字體是不是在你的資產文件夾 –