我创建了一个应用程序，用于从网址加载图片并使用CarouselWidget
在封面视图中显示它们当我第一次在Genymotion中运行我的应用程序时，它会下载数据库，从查询中获取结果，但不构建覆盖流。当我第二次运行它时，它会构建视图。为什么它没有第一次构建它？我在onPostExecute方法中包含了coverflow构建。
当我在真实设备上运行时，我总是看到白色屏幕。当我在调试模式下在设备上运行它并执行步骤时，它运行正常。如果我没有收到任何错误，如何在设备上调试？
如何动态加载图片？不是所有的都在同一时间，而是在滑动过程中。
这是我的代码。
public class MainActivity extends AppCompatActivity {
private static final String TAG = "qwe";
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private static final String DB1_NAME = "SuperupDB.sqlite";
private static final String DB2_NAME = "InventoryDB.sqlite";
private static final String DB_URL = "https://storage.googleapis.com/shared_data/MKGn299XpJ6mn9c6/clientsync/db/SuperupDB.zip";
private String dbQuery;
private ProgressDialog mProgressDialog;
private static String DB_PATH;
private CoverFlowAdapter mAdapter;
private ArrayList<Bitmap> mData = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (android.os.Build.VERSION.SDK_INT >= 17) {
DB_PATH = this.getApplicationInfo().dataDir + "/databases/";
} else {
DB_PATH = "/data/data/" + this.getPackageName() + "/databases/";
}
File dbFile1 = new File(DB_PATH + DB1_NAME);
File dbFile2 = new File(DB_PATH + DB2_NAME);
Log.d(TAG, dbFile1.getPath() + " " + dbFile1.exists());
Log.d(TAG, dbFile2.getPath() + " " + dbFile2.exists());
dbQuery = "Select p.PrdImgURL, cp.PrdID " +
"from Products as p " +
"inner join CategoryProduct_MM as cp " +
"on p.PrdID = cp.PrdID " +
"inner join InventoryDB.Facing as f " +
"on p.PrdID = f.PrdID " +
"where cp.CategoryID == 1 " +
"and p.PrdImgURL is not null " +
"order by f.`Order`";
if (dbFile1.exists() && dbFile2.exists()) {
loadProducts();
} else {
new DownloadDB().execute(DB_URL);
}
}
private void loadProducts() {
dbHandler dbh = dbHandler.getInstance(this);
SQLiteDatabase db = dbh.getWritableDatabase();
// attach second db to get products order from it
db.execSQL("attach database ? as InventoryDB", new String[]{DB_PATH + DB2_NAME});
db.beginTransaction();
Cursor c = db.rawQuery(dbQuery, null);
int count = c.getCount();
String url[] = new String[count];
int i = 0;
while (c.moveToNext()) {
url[i] = c.getString(c.getColumnIndex("PrdImgURL"));
i++;
}
for (i = 0; i < url.length; i++) {
loadBitmap(url[i]);
Log.d(TAG, url[i]);
}
mAdapter = new CoverFlowAdapter(getApplicationContext());
mAdapter.setData(mData);
CoverFlowCarousel mCoverFlow = (CoverFlowCarousel) findViewById(R.id.coverflow);
mCoverFlow.setAdapter(mAdapter);
}
private void loadBitmap(final String url) {
RequestQueue queue = Volley.newRequestQueue(this);
ImageRequest imageRequest = new ImageRequest(url,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
//mData.add(bitmap);
mData.add(addShadow(bitmap, bitmap.getHeight(), bitmap.getWidth(), Color.BLACK, 7, 3, 7));
}
}, 0, 0, null,
new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
Log.d(TAG, "loadBitmap: " + error.toString());
}
});
queue.add(imageRequest);
}
public Bitmap addShadow(final Bitmap bm, final int dstHeight, final int dstWidth, int color, int size, float dx, float dy) {
final Bitmap mask = Bitmap.createBitmap(dstWidth, dstHeight, Bitmap.Config.ALPHA_8);
final Matrix scaleToFit = new Matrix();
final RectF src = new RectF(0, 0, bm.getWidth(), bm.getHeight());
final RectF dst = new RectF(0, 0, dstWidth - dx, dstHeight - dy);
scaleToFit.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
final Matrix dropShadow = new Matrix(scaleToFit);
dropShadow.postTranslate(dx, dy);
final Canvas maskCanvas = new Canvas(mask);
final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
maskCanvas.drawBitmap(bm, scaleToFit, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY));
maskCanvas.drawBitmap(bm, dropShadow, paint);
final BlurMaskFilter filter = new BlurMaskFilter(size, BlurMaskFilter.Blur.NORMAL);
paint.reset();
paint.setAntiAlias(true);
paint.setColor(color);
paint.setMaskFilter(filter);
paint.setFilterBitmap(true);
final Bitmap ret = Bitmap.createBitmap(dstWidth + size, dstHeight + size, Bitmap.Config.ARGB_8888);
final Canvas retCanvas = new Canvas(ret);
retCanvas.drawBitmap(mask, 0, 0, paint);
retCanvas.drawBitmap(bm, scaleToFit, null);
mask.recycle();
return ret;
}
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_DOWNLOAD_PROGRESS:
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Loading database..");
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setCancelable(false);
mProgressDialog.show();
return mProgressDialog;
default:
return null;
}
}
class DownloadDB extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_PROGRESS);
}
@Override
protected String doInBackground(String... aurl) {
int count;
try {
URL url = new URL(aurl[0]);
URLConnection conn = url.openConnection();
conn.connect();
long lengthOfFile = conn.getContentLength();
Log.d(TAG, "Length of file: " + lengthOfFile);
InputStream input = new BufferedInputStream(url.openStream());
ZipInputStream zis = new ZipInputStream(input);
//default database directory
File dbDir = new File(DB_PATH);
if (!dbDir.exists())
dbDir.mkdir();
try {
ZipEntry ze;
while ((ze = zis.getNextEntry()) != null) {
if (ze.getName().equals(DB1_NAME) || ze.getName().equals(DB2_NAME)) {
lengthOfFile = ze.getSize();
FileOutputStream fout = new FileOutputStream(new File(dbDir, ze.getName()));
byte[] data = new byte[1024];
long total = 0;
while ((count = zis.read(data)) != -1) {
total += count;
publishProgress("" + (int) ((total * 100) / lengthOfFile));
fout.write(data, 0, count);
}
zis.closeEntry();
fout.close();
}
}
} catch (Exception e) {
Log.d(TAG, e.toString());
} finally {
zis.close();
}
} catch (Exception e) {
Log.d(TAG, e.toString());
}
return null;
}
protected void onProgressUpdate(String... progress) {
Log.d(TAG, progress[0]);
mProgressDialog.setProgress(Integer.parseInt(progress[0]));
}
@Override
protected void onPostExecute(String unused) {
dismissDialog(DIALOG_DOWNLOAD_PROGRESS);
loadProducts();
}
}
}
public class dbHandler extends SQLiteOpenHelper {
private static final int VERSION = 1;
private static final String DATABASE_NAME = "SuperupDB.sqlite";
private static final String TAG = "qwe";
private static File DATABASE_FILE;
// This is an indicator if we need to copy the
// database file.
private boolean mInvalidDatabaseFile = false;
private boolean mIsUpgraded = false;
private Context mContext;
/**
* number of users of the database connection.
*/
private int mOpenConnections = 0;
private static dbHandler mInstance;
synchronized static public dbHandler getInstance(Context context) {
if (mInstance == null) {
mInstance = new dbHandler(context.getApplicationContext());
}
return mInstance;
}
private dbHandler(Context context) {
super(context, DATABASE_NAME, null, VERSION);
this.mContext = context;
SQLiteDatabase db = null;
try {
db = getReadableDatabase();
if (db != null) {
db.close();
}
DATABASE_FILE = context.getDatabasePath(DATABASE_NAME);
/* if (mInvalidDatabaseFile) {
//copyDatabase();
Log.d(TAG, "Where is db?");
}*/
if (mIsUpgraded) {
doUpgrade();
}
} catch (SQLiteException e) {
} finally {
if (db != null && db.isOpen()) {
db.close();
}
}
}
@Override
public void onCreate(SQLiteDatabase db) {
//mInvalidDatabaseFile = true;
}
@Override
public void onUpgrade(SQLiteDatabase database,
int old_version, int new_version) {
//mInvalidDatabaseFile = true;
mIsUpgraded = true;
}
/**
* called if a database upgrade is needed
*/
private void doUpgrade() {
// implement the database upgrade here.
}
@Override
public synchronized void onOpen(SQLiteDatabase db) {
super.onOpen(db);
// increment the number of users of the database connection.
mOpenConnections++;
if (!db.isReadOnly()) {
// Enable foreign key constraints
db.execSQL("PRAGMA foreign_keys=ON;");
}
}
/**
* implementation to avoid closing the database connection while it is in
* use by others.
*/
@Override
public synchronized void close() {
mOpenConnections--;
if (mOpenConnections == 0) {
super.close();
}
}
private void setDatabaseVersion() {
SQLiteDatabase db = null;
try {
db = SQLiteDatabase.openDatabase(DATABASE_FILE.getAbsolutePath(), null,
SQLiteDatabase.OPEN_READWRITE);
db.execSQL("PRAGMA user_version = " + VERSION);
} catch (SQLiteException e) {
} finally {
if (db != null && db.isOpen()) {
db.close();
}
}
}
}
答案 0 :(得分：0)
通过Universal Image Loader加载延迟图像解决了这个问题 Here is the example
答案 1 :(得分：0)
解决此问题的另一种方法是在应用程序的style.xml文件中添加以下行：
<item name="android:windowDisablePreview">true</item>