Question

我正在尝试从应用程序的assets文件夹中复制数据库。代码在Android 2.1 / 2.3上完美运行，但是当我在Android 2.2设备上执行相同的代码时，它会引发异常：

09-03 15:54:09.762: I/System.out(610): File Created successfully
09-03 15:54:09.762: D/asset(610): Data exceeds UNCOMPRESS_DATA_MAX (4640768 vs 1048576)
09-03 15:54:09.762: W/System.err(610): java.io.IOException
09-03 15:54:09.782: W/System.err(610):  at android.content.res.AssetManager.readAsset(Native Method)
09-03 15:54:09.782: W/System.err(610):  at android.content.res.AssetManager.access$700(AssetManager.java:36)
09-03 15:54:09.862: D/dalvikvm(610): GC_FOR_MALLOC freed 2198 objects / 260688 bytes in 71ms
09-03 15:54:09.862: W/System.err(610):  at android.content.res.AssetManager$AssetInputStream.read(AssetManager.java:571)
09-03 15:54:09.862: W/System.err(610):  at com.emobi.metro.Help.createDatabase(Help.java:39)
09-03 15:54:09.862: W/System.err(610):  at com.emobi.metro.Help.<init>(Help.java:22)
09-03 15:54:09.862: W/System.err(610):  at com.emobi.metro.Fair.onCreate(Fair.java:41)
09-03 15:54:09.862: W/System.err(610):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-03 15:54:09.862: W/System.err(610):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-03 15:54:09.862: W/System.err(610):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-03 15:54:09.862: W/System.err(610):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-03 15:54:09.862: W/System.err(610):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-03 15:54:09.862: W/System.err(610):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-03 15:54:09.862: W/System.err(610):  at android.os.Looper.loop(Looper.java:123)
09-03 15:54:09.862: W/System.err(610):  at android.app.ActivityThread.main(ActivityThread.java:4627)
09-03 15:54:09.862: W/System.err(610):  at java.lang.reflect.Method.invokeNative(Native Method)
09-03 15:54:09.862: W/System.err(610):  at java.lang.reflect.Method.invoke(Method.java:521)
09-03 15:54:09.862: W/System.err(610):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-03 15:54:09.862: W/System.err(610):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-03 15:54:09.862: W/System.err(610):  at dalvik.system.NativeStart.main(Native Method)

以下功能用于从资产中复制数据库：

private void createDatabase() {
    File DbFile = new File(
            "data/data/com.emobi.metro/databases/mymetro");
    if (DbFile.exists()) {
        System.out.println("file already exist ,No need to Create");
    } else {
        try {
            DbFile.createNewFile();
            System.out.println("File Created successfully");
            InputStream is = context.getAssets().open(databasename);
            FileOutputStream fos = new FileOutputStream(DbFile);
            byte[] buffer = new byte[1024];
            int length = 0;
            while ((length = is.read(buffer)) > 0) {
                fos.write(buffer, 0, length);
            }
            System.out.println("File succesfully placed on sdcard");
            // Close the streams
            fos.flush();
            fos.close();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

是的我也试过了，但后来我得到了Exception 09-03 16:14:26.652: E/AndroidRuntime(2165): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.emobi.metro/com.emobi.metro.Fair}: android.database.sqlite.SQLiteException: no such table: fair: , while compiling: select stations from fair

数据库中有哪些。

Answer 1

在网上有很多可能的解决方案，这里有关于stackoverflow的一个很好的讨论：I get this error: Data exceeds UNCOMPRESS_DATA_MAX on android 2.2 but not on 2.3

似乎与android压缩1 mb以上的文件有关。

Answer 2

您的数据超过1 MB以上在这种情况下，只需将数据库名称重命名为dbname.mp3

private void copyDataBase() throws IOException {

        try {
            // Open your local db as the input stream
            InputStream myInput = context.getAssets().open("databases/" + DB_NAME + ".mp3");

            // Path to the just created empty db
            String outFileName = DB_PATH + DB_NAME;

            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();
        } catch (Exception e) {

            Log.e("Error in copy DB", e.toString());

        }

    }

Answer 3

使用winzip真正压缩数据库并将zip放入资产文件夹，在运行时解压缩并将其复制到数据库文件夹。

无法从Assets文件夹复制数据库

3 个答案: