初始化数据库时显示进度条

Question

I'm in the progress of moving my Sqlite DB in my Android app to a Room implementation. On first setup the database needs to be populated from a CSV shipped with the apk (this can't be changed). This can take up to 30 seconds during which I display a progress bar to the user and block them from proceeding. I find this a better experience for the user then them waiting for data to appear on first query.

In my current implementation I subclass SQLiteOpenHelper, providing a Handler field that I can set before calling getReadableDatabase (which has always seemed a bit of a hack). Progress can then be returned to the calling Handler. However in Room implementation the database is initialised by a callback on the Dagger2 provided Room database. Question is how can I still show a progress dialog to the user during this setup?

DatabaseModule

 package uk.colessoft.android.hilllist.modules;


import android.app.Application;
import android.arch.persistence.db.SupportSQLiteDatabase;
import android.arch.persistence.db.SupportSQLiteOpenHelper;
import android.arch.persistence.room.Room;
import android.arch.persistence.room.RoomDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.support.annotation.NonNull;

import javax.inject.Singleton;

import dagger.Binds;
import dagger.Module;
import dagger.Provides;
import uk.colessoft.android.hilllist.dao.HillDao;
import uk.colessoft.android.hilllist.dao.HillTypeDao;
import uk.colessoft.android.hilllist.dao.TypeLinkDao;
import uk.colessoft.android.hilllist.database.BaggingTable;
import uk.colessoft.android.hilllist.database.BritishHillsDatasource;
import uk.colessoft.android.hilllist.database.HillsDatabase;
import uk.colessoft.android.hilllist.database.HillsDatabaseHelper;
import uk.colessoft.android.hilllist.database.HillsLocalDatasource;
import uk.colessoft.android.hilllist.database.HillsTables;

import static android.arch.persistence.room.RoomDatabase.JournalMode.TRUNCATE;

@Module
public class DatabaseModule {



    @Provides
    @Singleton
    HillsDatabase providesRoomDatabase(Application application) {

        return Room.databaseBuilder(application, HillsDatabase.class, "hill-list.db").addMigrations(HillsDatabase.MIGRATION_2_3)
                .addCallback(new RoomDatabase.Callback() {
                    @Override
                    public void onCreate(@NonNull SupportSQLiteDatabase db) {
                        HillsTables.onCreate(db, application);//, handler, 9999999);
                    }
                }).setJournalMode(TRUNCATE).build();
    }

    @Provides
    @Singleton
    HillDao providesHillDao(HillsDatabase database) {
        return database.hillDao();
    }

    @Provides
    @Singleton
    HillTypeDao providesHillTypeDao(HillsDatabase database) {
        return database.hillTypeDao();
    }

    @Provides
    @Singleton
    TypeLinkDao providesTypeLinkDao(HillsDatabase database) {
        return database.typeLinkDao();
    }
}

HillsTables

package uk.colessoft.android.hilllist.database;

import android.arch.persistence.db.SupportSQLiteDatabase;
import android.arch.persistence.db.SupportSQLiteStatement;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteStatement;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import static android.content.ContentValues.TAG;

public class HillsTables {

    private static final String HILLS_CSV = "DoBIH_v15.5.csv";

    public static final String KEY_TITLE = "title";
    public static final String HILLS_TABLE = "hills";
    public static final String HILLTYPES_TABLE = "hilltypes";
    public static final String TYPES_LINK_TABLE = "typeslink";
    public static final String KEY_ID = "_id";
    public static final String KEY_HILLNAME = "Name";
    public static final String KEY_SECTION = "Section";
    public static final String KEY_SECTIONNAME = "Section name";
    public static final String KEY_AREA = "Area";
    public static final String KEY_CLASSIFICATION = "Classification";
    public static final String KEY_MAP = "Map 1:50k";
    public static final String KEY_MAP25 = "Map 1:25k";
    public static final String KEY_HEIGHTM = "Metres";
    public static final String KEY_HEIGHTF = "Feet";
    public static final String KEY_GRIDREF = "Grid ref";
    public static final String KEY_GRIDREF10 = "Grid ref 10";
    public static final String KEY_DROP = "Drop";
    public static final String KEY_COLGRIDREF = "Col grid ref";
    public static final String KEY_COLHEIGHT = "Col height";
    public static final String KEY_FEATURE = "Feature";
    public static final String KEY_OBSERVATIONS = "Observations";
    public static final String KEY_SURVEY = "Survey";
    public static final String KEY_CLIMBED = "Climbed";
    public static final String KEY_REVISION = "Revision";
    public static final String KEY_COMMENTS = "Comments";
    public static final String KEY_STREETMAP = "Streetmap/OSiViewer";
    public static final String KEY_GEOGRAPH = "Geograph/MountainViews";
    public static final String KEY_HILLBAGGING = "Hill-bagging";
    public static final String KEY_XCOORD = "Xcoord";
    public static final String KEY_YCOORD = "Ycoord";
    public static final String KEY_LATITUDE = "Latitude";
    public static final String KEY_LONGITUDE = "Longitude";
    public static final String KEY_XSECTION = "_Section";
    public static final String KEY_HILL_ID = "hill_id";
    public static final String KEY_TYPES_ID = "type_id";


    private static final String HILLTYPES_CREATE = "CREATE TABLE "
            + HILLTYPES_TABLE + "(" + KEY_ID + " integer primary key," + KEY_TITLE + " unique)";

    private static final String TYPESLINK_CREATE = "CREATE TABLE "
            + TYPES_LINK_TABLE + "(" + KEY_ID
            + " integer primary key autoincrement," + KEY_HILL_ID
            + " references " + HILLS_TABLE + "(" + KEY_ID + ")," + KEY_TYPES_ID
            + " references " + HILLTYPES_TABLE + "(" + KEY_ID + "))";
    private static Handler handler;


    public static void onCreate(SupportSQLiteDatabase database, Context context){//, Handler handler, int rows) {

        //createSimpleTables(database);
        //HillsTables.handler = handler;
        long startTime = System.currentTimeMillis();



        createAndPopulateHillsTable(database, context, startTime);//, rows);

        populateHillTypes(database, startTime);



    }

    static void populateHillTypes(SupportSQLiteDatabase database, long startTime) {

        Cursor c = database.query("select * from "+HILLS_TABLE);
        SupportSQLiteStatement insertHillType = database.compileStatement("INSERT or IGNORE into " + HILLTYPES_TABLE + " VALUES(?,?)");
        SupportSQLiteStatement insertHillTypeLink = database.compileStatement("INSERT into " + TYPES_LINK_TABLE + " (" + KEY_HILL_ID + "," + KEY_TYPES_ID + ") values (?,?)");

        // Populate static hill types data
        database.beginTransaction();
        if (c.moveToFirst()) {
            do {
                String[] classifications = c.getString(c.getColumnIndex(KEY_CLASSIFICATION)).replace("\"", "").split(",");
                for (String classification : classifications) {
                    insertHillType.bindString(2, classification);
                    insertHillType.bindLong(1, c.getColumnIndex(classification));
                    insertHillType.executeInsert();

                    insertHillTypeLink.bindLong(1, c.getInt(0));
                    insertHillTypeLink.bindLong(2, c.getColumnIndex(classification));
                    insertHillTypeLink.executeInsert();
                }
            } while (c.moveToNext());
        }
        database.setTransactionSuccessful();
        database.endTransaction();
        c.close();
        Log.d(TAG, "populateHillTypes: Finished inserting hill types information after "
                        + (System.currentTimeMillis() - startTime) / 1000);
    }

    private static void createAndPopulateHillsTable(SupportSQLiteDatabase database, Context context, long startTime){//, int rows) {
        InputStream is;
        Log.d(TAG, "createAndPopulateHillsTable: starting");
        try {

            is = context.getAssets().open(HILLS_CSV);
            BufferedReader reader = new BufferedReader(
                    new InputStreamReader(is));

            //createHillsTable(database, reader);
            String headerRow = reader.readLine();

            StringBuffer insertHillsBuffer;


            // read main hill data into hills table
            database.beginTransaction();
            String line;
            int count = 0;
            while ((line = reader.readLine()) != null && count <= 23000) {
                count++;
                if(handler != null) {
                    handler.dispatchMessage(Message.obtain(handler, 0, 0, 1, 1));
                }

                insertHillsBuffer = new StringBuffer();
                insertHillsBuffer.append("INSERT INTO " + HILLS_TABLE
                        + " VALUES (");
                String[] lineArray = line
                        .split(",(?=([^\"]*\"[^\"]*\")*[^\"]*$)");

                for (String entry : lineArray) {
                    insertHillsBuffer.append("'").append(entry.replace("'", "''")).append("',");
                }
                insertHillsBuffer.deleteCharAt(insertHillsBuffer.length() - 1);

                insertHillsBuffer.append(")");
                database.execSQL(insertHillsBuffer.toString());
            }

            database.setTransactionSuccessful();
            database.endTransaction();
            Log.d(TAG,
                    "#################Finished inserting base hill information after "
                            + (System.currentTimeMillis() - startTime) / 1000);
        } catch (IOException e) {
            Log.e(TAG,
                    "Failed to populate hills database table", e);
        }
    }

    private static void createHillsTable(SupportSQLiteDatabase database, BufferedReader reader) throws IOException {
        String headerRow = reader.readLine();
        String hillsTableStarter = "CREATE TABLE '" + HILLS_TABLE
                + "' ('" + KEY_ID + "' integer primary key,";
        String[] headerArray = headerRow.split(",");
        StringBuilder createHillsTableBuilder = new StringBuilder();
        for (String header : headerArray) {
            header = header.replace("\uFEFF","");
            if (!"Number".equals(header)) {
                createHillsTableBuilder.append("'").append(header).append("',");
            }
        }
        String c = createHillsTableBuilder.toString();
        database.execSQL(hillsTableStarter + c.substring(0, c.length() - 1) + ")");
    }

    private static void createSimpleTables(SupportSQLiteDatabase database) {
        database.execSQL("PRAGMA foreign_keys=ON;");
        database.execSQL(HILLTYPES_CREATE);
        database.execSQL(TYPESLINK_CREATE);
    }

    public static void onUpgrade(SupportSQLiteDatabase database, int oldVersion,
                                 int newVersion, Context context, Handler handler, int rows) {
        Log.w(HillsTables.class.getName(), "Upgrading database from version "
                + oldVersion + " to " + newVersion
                + ", which will destroy all old hills data");
        database.execSQL("DROP TABLE IF EXISTS " + HILLS_TABLE);
        database.execSQL("DROP TABLE IF EXISTS " + HILLTYPES_TABLE);
        database.execSQL("DROP TABLE IF EXISTS " + TYPES_LINK_TABLE);
        //onCreate(database, context, handler, rows);
    }

}

SplashScreenActivity

package uk.colessoft.android.hilllist.activities;

import android.Manifest;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.text.util.Linkify;
import android.widget.TextView;

import javax.inject.Inject;

import uk.colessoft.android.hilllist.BHApplication;
import uk.colessoft.android.hilllist.R;
import uk.colessoft.android.hilllist.database.BritishHillsDatasource;

public class SplashScreenActivity extends AppCompatActivity {

    private static final int MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE = 0x00001;
    public static final int MAX = 20782;
    private Thread splashThread;
    private Handler handler;
    private ProgressDialog progressDialog;

    @Inject
    BritishHillsDatasource dbAdapter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        ((BHApplication) getApplication()).getDbComponent().inject(this);

        setContentView(R.layout.splash);
        TextView link=(TextView) findViewById(R.id.TextView03);
        Linkify.addLinks(link, Linkify.ALL);

        handler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                if(msg.arg1 == 0)
                    progressDialog.incrementProgressBy(1);
                else {
                    SplashScreenActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER);
                    progressDialog.cancel();
                }
            }
        };

        progressDialog = new ProgressDialog(SplashScreenActivity.this);
        progressDialog.setTitle("Updating Database");
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        progressDialog.setMax(MAX);
        progressDialog.setCancelable(false);
        progressDialog.setCanceledOnTouchOutside(false);
        progressDialog.show();


        splashThread = new Thread() {

            @Override
            public void run() {


                SplashScreenActivity.this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_NOSENSOR);


                dbAdapter.touch(handler);
                handler.sendMessage(Message.obtain(handler, 0, 1, 1, 1));

                try {

                    int waited = 0;

                    while (waited < 1800) {

                        sleep(100);

                        waited += 100;

                    }

                } catch (InterruptedException e) {

                    // do nothing

                } finally {

                    finish();
                    Intent i = new Intent(SplashScreenActivity.this,

                            Main.class);

                    startActivity(i);

                }

            }

        };

        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {

                showMessageOKCancel("You need to allow access to the SD Card to read and write the Database",
                        (dialog, which) -> ActivityCompat.requestPermissions(SplashScreenActivity.this,
                                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                                MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE));

            } else {

                // No explanation needed, we can request the permission.

                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE);

            }
        }else {
            splashThread.start();

        }


    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    splashThread.start();


                } else {
                    finish();
                }

            }

        }
    }

    private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
        new AlertDialog.Builder(SplashScreenActivity.this)
                .setMessage(message)
                .setPositiveButton("OK", okListener)
                .create()
                .show();
    }

}

Answer 1

Try use ProgressBar with AsyncTask . Here are the helpful links: https://stackoverflow.com/a/15487920/9626373 https://stackoverflow.com/a/9963705/9626373