android 数据库更改数据库位置【DbFlow示范】

    //初始化数据库    public static void initDB() {        boolean premission = PermissionUtils.isPremission(context, Manifest.permission.WRITE_EXTERNAL_STORAGE);        if (!premission) return;        File file = CreatFileUtil.getRootFile(getApplication());        FileDatabaseContext mSdDatabaseContext = new FileDatabaseContext(context, file, true);        FlowManager.init(mSdDatabaseContext);    }    //重新加载数据库    public static void deleteDB() {        File file = CreatFileUtil.getRootFile(getApplication());        file.delete();        FlowManager.destroy();// 释放引用，才能重新创建表        initDB();    }

package com.jtv.operation.dao;import android.content.Context;import android.content.ContextWrapper;import android.database.DatabaseErrorHandler;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.text.TextUtils;import com.raizlabs.android.dbflow.config.FlowLog;import java.io.File;import java.io.FileOutputStream;import java.io.InputStream;/** * 支持数据库任意地址 *  * 支持使用打包的数据库res/raw/initdb.db * * @author 更生 * @version 2017年3月2日 */public class FileDatabaseContext extends ContextWrapper {    private File file;    private boolean isUseDefaultDB;    private Context context;    /**     * @param base           上下文     * @param file           文件存储目录     * @param isUseDefaultDB 是否使用raw/initdb.db文件     */    public FileDatabaseContext(Context base, File file, boolean isUseDefaultDB) {        super(base);        this.file = file;        this.context = base;        this.isUseDefaultDB = isUseDefaultDB;    }    @Override    public Context getApplicationContext() {        return this;    }    @Override    public File getDatabasePath(String name) {        //携带数据库        if (isUseDefaultDB) {            File tempFile = file;            if (tempFile == null)                tempFile = context.getDatabasePath(name).getParentFile();            createInitDatabase(tempFile, name, context);        }        if (file == null)            return context.getDatabasePath(name);        // 判断目录是否存在，不存在则创建该目录        if (!file.exists())            file.mkdirs();        File addressFile = new File(file, name);        if (addressFile == null)            addressFile = context.getDatabasePath(name);        return addressFile;    }    public boolean createInitDatabase(File toFile, String name, Context context) {        String path = toFile.getAbsolutePath();        if (TextUtils.isEmpty(path))            return false;        // 判断数据文件是否存在，不存在的话使用打包的数据文件        String toFileName = path + File.separator + name;        File f = new File(toFileName);        if (f == null || f.exists())            return false;        File dir = new File(path);        if (dir == null) return false;        if (!dir.exists())            dir.mkdirs();        InputStream is = null;        FileOutputStream fos = null;        try {            is = context.getResources().openRawResource(context.getResources().getIdentifier("initdb", "raw", context.getPackageName()));            // 创建输出流            fos = new FileOutputStream(toFileName);            // 将数据输出            byte[] buffer = new byte[8192];            int count = 0;            while ((count = is.read(buffer)) > 0) {                fos.write(buffer, 0, count);            }            buffer = null;        } catch (Exception ee) {            FlowLog.log(FlowLog.Level.I, ee.toString());        } finally {            try {                fos.close();            } catch (Exception ee) {            }            try {                is.close();            } catch (Exception ee) {            }        }        return true;    }    //重载这个方法，是用来打开SD卡上的数据库的，android 2.3及以下会调用这个方法。    @Override    public SQLiteDatabase openOrCreateDatabase(String name, int mode, CursorFactory factory) {        SQLiteDatabase result = SQLiteDatabase.openOrCreateDatabase(getDatabasePath(name), null);        return result;    }    //Android 4.0会调用此方法获取数据库。    @Override    public SQLiteDatabase openOrCreateDatabase(String name, int mode, CursorFactory factory,                                               DatabaseErrorHandler errorHandler) {        SQLiteDatabase result = SQLiteDatabase.openOrCreateDatabase(getDatabasePath(name), null);        return result;    }}

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