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我是Android开发新手。
我想完成我的应用程序，这个应用程序将数据保存到SQLite数据库，显示，更新，删除等。但是当我试图显示数据库中的所有行时，这需要太多的时间。我想添加一个ProgressBar来向用户显示它正在花费时间。在保存/显示SQLite数据库时显示ProgressBar
在这段代码中，我可以添加一个ProgressBar吗？
这是MainActivity：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Instantiate database handler
db=new DatabaseHandler(this);
lv = (ListView) findViewById(R.id.list1);
pic = (ImageView) findViewById(R.id.pic);
nazev =(EditText) findViewById(R.id.nazev);
objem =(EditText) findViewById(R.id.objem);
obsah_alkoholu =(EditText) findViewById(R.id.obsah_alkoholu);
aroma =(EditText) findViewById(R.id.aroma);
chut =(EditText) findViewById(R.id.chut);
dokonceni =(EditText) findViewById(R.id.dokonceni);
poznamka =(EditText) findViewById(R.id.poznamka);
vsechnyradky =(TextView) findViewById(R.id.textView);
ShowRecords();
}
public void buttonClicked(View v){
int id=v.getId();
switch(id){
case R.id.save:
if(nazev.getText().toString().trim().equals("")){
Toast.makeText(getApplicationContext(),"Není název.", Toast.LENGTH_LONG).show();
} else{
addRumy();
}
ShowRecords();
break;
case R.id.display:
ShowRecords();
break;
case R.id.pic:
selectImage();
break;
}
}
public void selectImage(){
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, 2);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode) {
case 2:
if(resultCode == RESULT_OK){
Uri choosenImage = data.getData();
if(choosenImage !=null){
bp=decodeUri(choosenImage, 400);
pic.setImageBitmap(bp);
}
}
}
}
//COnvert and resize our image to 400dp for faster uploading our images to DB
protected Bitmap decodeUri(Uri selectedImage, int REQUIRED_SIZE) {
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o);
// The new size we want to scale to
// final int REQUIRED_SIZE = size;
// Find the correct scale value. It should be the power of 2.
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp/2 < REQUIRED_SIZE
|| height_tmp/2 < REQUIRED_SIZE) {
break;
}
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o2);
}
catch (Exception e){
e.printStackTrace();
}
return null;
}
//Convert bitmap to bytes
@TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
private byte[] profileImage(Bitmap b){
ByteArrayOutputStream bos = new ByteArrayOutputStream();
b.compress(Bitmap.CompressFormat.PNG, 0, bos);
return bos.toByteArray();
}
// function to get values from the Edittext and image
private void getValues(){
f_nazev = nazev.getText().toString();
f_objem = objem.getText().toString();
f_obsah_alkoholu = obsah_alkoholu.getText().toString();
f_aroma = aroma.getText().toString();
f_chut = chut.getText().toString();
f_dokonceni = dokonceni.getText().toString();
f_poznamka = poznamka.getText().toString();
photo = profileImage(bp);
}
//Insert data to the database
private void addRumy(){
getValues();
db.addRumy(new Rumy(f_nazev, f_objem, f_obsah_alkoholu, f_aroma, f_chut, f_dokonceni, f_poznamka, photo));
showProgressDialogHorizontal();
db.close();
}
//Retrieve data from the database and set to the list view
private void ShowRecords(){
final ArrayList<Rumy> rumy = new ArrayList<>(db.getAllRumy());
data=new DataAdapter(this, rumy);
lv.setAdapter(data);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
dataModel = rumy.get(position);
final Dialog openDialog = new Dialog(context2);
openDialog.setContentView(R.layout.dialogove_okno_mazani);
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setTitle("Souhrn záznamu k odeslání:");
alertDialog.setMessage("Opravdu si přejete smazat tento záznam???");
alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "Zpět",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
alertDialog.setButton(AlertDialog.BUTTON_NEGATIVE, "Zrušit mazání",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
startActivity(getIntent());
}
});
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "Smazat trvale!",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// db.deleteRumy(String.valueOf(dataModel.getID()));
showProgressDialogHorizontal();
db.clearDatabase();
db.close();
// ShowRecords();
finish();
// Toast.makeText(getApplicationContext(),String.valueOf(dataModel.getID()), Toast.LENGTH_SHORT).show();
// startActivity(getIntent());
}
});
alertDialog.show();
}
});
}}
db.getAllRumy
public List<Rumy> getAllRumy() {
List<Rumy> rumytList = new ArrayList<Rumy>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Rumy rumy = new Rumy();
rumy.setID(Integer.parseInt(cursor.getString(0)));
rumy.setNazev(cursor.getString(1));
rumy.setObjem(cursor.getString(2));
rumy.setObsahAlkoholu(cursor.getString(3));
rumy.setAroma(cursor.getString(4));
rumy.setChut(cursor.getString(5));
rumy.setDokonceni(cursor.getString(6));
rumy.setPoznamka(cursor.getString(7));
rumy.setFoto(cursor.getBlob(8));
// Adding contact to list
rumytList.add(rumy);
} while (cursor.moveToNext());
}
// return contact list
return rumytList;
}
凡在我的代码，我失去了:( – zajicek