How import/export sqlite database in nativescript/angular android?

问题

I'm trying to export the whole sqlite database into sd card memory with a button click for a project (Backup feature). I googled for the same, but seems negative response. I'm using https://github.com/NathanaelA/nativescript-sqlite plugin for this. Also need to import the exported database with file picker. Right now, I'm trying to reach it using java code with nativescript. Any nativescript way help will be appreciated. Thanks in advance.

回答1:

my solution to export database for android was to create a developer page and add a button in it :

EDITED

<Button class="btn  m-3" height="50" row="1" text="ExportDB" (tap)="exportDb()"></Button>

the tap function code is :

public exportDb() {
    console.log('######################### exporting DB ##################');
    this.copyAndroidFileUsingStream('/data/data/{your package name }/databases/{database name}.db',
        fs.path.join(this.getDownloadFolderPath(), {output filename}.db));
}

public getDownloadFolderPath() {
    if (!!application.ios) {
        const fileManager = utilModule.ios.getter(NSFileManager, NSFileManager.defaultManager);
        const paths = fileManager.URLsForDirectoryInDomains(15, 1);
        const url = paths.objectAtIndex(0);
        return url.path;
    } else {
        return android.os.Environment.getExternalStoragePublicDirectory(
            android.os.Environment.DIRECTORY_DOWNLOADS).toString();
    }
}

// copy file only for android
    public copyAndroidFileUsingStream = (source, dest): void => {
        let is: java.io.InputStream = null;
        let os: java.io.OutputStream = null;
        try {
            is = new java.io.FileInputStream(source);
            os = new java.io.FileOutputStream(dest);
            //    let buffer = Array.create("byte", 1024);

            const buffer = Array.create('byte', 4096);
            let length: number;
            // tslint:disable-next-line:no-conditional-assignment
            while ((length = is.read(buffer)) > 0) {
                os.write(buffer, 0, length);
            }
        } catch (e) {
            this.errorService.handleError(e);
        } finally {
            console.log('copy done');
            is.close();
            os.close();
        }
    }

来源：https://stackoverflow.com/questions/49144729/how-import-export-sqlite-database-in-nativescript-angular-android