Android数据库备份和恢复

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import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.text.SimpleDateFormat;
import java.util.Date;
  
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.AsyncTask;
import android.os.Environment;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ProgressBar;
import android.widget.Toast;
  
public class BackupAndRestore {
    private Context mContext = null;
    private String[] fileList = null; // 数据库文件列表
    private int choicePostion = -3; // 选择数据库列表中的位置
    private AlertDialog dialog = null;
    private String BACK_FOLDER = "backup";
    private String appName = "myApp";
  
    public BackupAndRestore(Context context) {
        mContext = context;
    }
  
    /**
     * 恢复数据的Dialog
     */
    public void restoreDB() {
        fileList = getFileList();
        AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
        builder.setIcon(android.R.drawable.ic_dialog_info);
        builder.setTitle("恢复");
        builder.setSingleChoiceItems(getFileList(),-1,new DialogClick());
        builder.setPositiveButton("确定",new DialogClick());
        builder.setNegativeButton("取消",new DialogClick());
        builder.show();
    }
  
    /**
     * 备份数据库
     */
    public void backupDB() {
        showDialog("是否备份数据库",'B');
    }
  
    /**
     * 显示一个Dialog
     * 
     * @param title
     *            标题 ，必须引用资源ID resource ID
     * @param sign
     *            根据标示调用方法 I - 恢复默认设置 D - 恢复默认设置 H -选择主机
     */
    private void showDialog(String title,char sign) {
        final char s = sign;
        new AlertDialog.Builder(mContext).setTitle(title)
                .setPositiveButton("确定",new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogI,int which) {
                        switch (s) {
                        case 'B': // 备份数据库
                            if (dialog == null) {
                                dialog = awaitDialog(mContext);
                            } else {
                                dialog.show();
                            }
                            new ExecuteTask().execute('B');
                            break;
                        default:
                            break;
                        }
                    }
                }).setNegativeButton("取消",new OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog,int which) {
                    }
                }).show();
    }
  
    /**
     * 备份操作
     * 
     * @return
     */
    private boolean backUp() {
        boolean isOk = false;
        String sp = File.separator;
        File sdFile = sdCardOk();
        if (sdFile != null) {
            try {
                String[] dbNames = { "数据库名称" };
                // 创建日期文件夹
                String folder_date = datePrefix();
                File f = new File(sdFile.getAbsolutePath() + sp + folder_date);
                if (!f.exists()) {
                    f.mkdirs();
                }
                for (int i = 0; i < dbNames.length; i++) {
                    String dbName = dbNames[i];
                    File dbFile = dbOk(dbName);
                    if (dbFile != null) {
                        File backFile = new File(f.getAbsolutePath() + sp
                                + dbFile.getName());
                        backFile.createNewFile();
                        isOk = fileCopy(backFile,dbFile.getAbsoluteFile());
                        if (!isOk) {
                            break;
                        }
                    }
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return isOk;
    }
  
    /**
     * 时间前缀
     * 
     * @return
     */
    private String datePrefix() {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
        Date date = new Date(System.currentTimeMillis());
        String str = format.format(date);
        return str;
    }
  
    /**
     * 文件夹列表
     * 
     * @return
     */
    private String[] getFileList() {
        String[] fileList = null;
        File file = sdCardOk();
        if (file != null) {
            File[] list = file.listFiles();
            if (list != null && list.length > 0) {
                fileList = new String[list.length];
                for (int i = 0; i < list.length; i++) {
                    fileList[i] = list[i].getName();
                }
            }
        }
        return fileList;
    }
  
    /**
     * sdCard是否存在 备份的文件夹是否存在
     * 
     * @return null不能使用
     */
    private File sdCardOk() {
        File bkFile = null;
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            String sp = File.separator;
            String backUpPath = Environment.getExternalStorageDirectory() + sp
                    + appName + sp + BACK_FOLDER;
            bkFile = new File(backUpPath);
            if (!bkFile.exists()) {
                bkFile.mkdirs();
            } else
                return bkFile;
        } else
            Toast.makeText(mContext,"Sdcard 不存在",Toast.LENGTH_SHORT).show();
        return bkFile;
    }
  
    /**
     * 恢复数据库
     * 
     * @param name
     *            选择的文件名称 选中的数据库名称
     * @param resoreDbName
     *            需要恢复的数据库名称
     * @return
     */
    public boolean restore(String name,File f) {
        boolean isOk = false;
        if (f != null) {
            File dbFile = dbOk(name);
            try {
                // System.out.println("覆盖的名称"+dbName);
                if (dbFile != null) {
                    isOk = fileCopy(dbFile,f.getAbsoluteFile());
                } else
                    isOk = false;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return isOk;
    }
  
    /**
     * 数据库文件是否存在，并可以使用
     * 
     * @return
     */
    private File dbOk(String dbName) {
        String sp = File.separator;
        String absPath = Environment.getDataDirectory().getAbsolutePath();
        String pakName = mContext.getPackageName();
        String dbPath = absPath + sp + "data" + sp + pakName + sp + "databases"
                + sp + dbName;
        File file = new File(dbPath);
        if (file.exists()) {
            return file;
        } else {
            return null;
        }
    }
  
    /**
     * 等候动画
     */
    public AlertDialog awaitDialog(Context context) {
        ProgressBar bar = new ProgressBar(context);
        bar.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
        AlertDialog dialog = new AlertDialog.Builder(context).create();
        dialog.setCancelable(false);
        dialog.show();
        Window window = dialog.getWindow();
        WindowManager.LayoutParams params = window.getAttributes();
        params.width = 50;
        params.height = 50;
        window.setAttributes(params);
        window.setContentView(bar);
        return dialog;
    }
  
    /**
     * 
     * @param outFile
     *            写入
     * @param inFile
     *            读取
     * @throws FileNotFoundException
     */
    private boolean fileCopy(File outFile,File inFile) throws IOException {
        if (outFile == null || inFile == null) {
            return false;
        }
        boolean isOk = true;
        FileChannel inChannel = new FileInputStream(inFile).getChannel();// 只读
        FileChannel outChannel = new FileOutputStream(outFile).getChannel();// 只写
        try {
            long size = inChannel.transferTo(0,inChannel.size(),outChannel);
            if (size <= 0) {
                isOk = false;
            }
        } catch (IOException e) {
            isOk = false;
            e.printStackTrace();
        } finally {
            if (inChannel != null) {
                inChannel.close();
            }
            if (outChannel != null) {
                outChannel.close();
            }
        }
        return isOk;
    }
  
    private class DialogClick implements DialogInterface.OnClickListener {
        @Override
        public void onClick(DialogInterface dialog,int which) {
            if (which == -1) {// 确定
                if (choicePostion < 0) {
                    Toast.makeText(mContext,"选择数据库",Toast.LENGTH_SHORT)
                            .show();
                    return;
                }
                String sp = File.separator;
                String folderName = fileList[choicePostion];
                String backUpPath = Environment.getExternalStorageDirectory()
                        + sp + appName + sp + BACK_FOLDER + sp + folderName;
                File file = new File(backUpPath);
                if (file.isDirectory()) {
                    File[] files = file.listFiles();
                    boolean isOk = false;
                    for (int i = 0; i < files.length; i++) {
                        File f = files[i];
                        isOk = restore(f.getName(),f);
                        if (!isOk) {
                            String fail_msg = "恢复失败" + ":" + f.getName();
                            Toast.makeText(mContext,fail_msg,Toast.LENGTH_SHORT).show();
                            return;
                        }
                    }
                    if (isOk) {
                        // 如果有数据体现则需要刷新出新的数据
  
                    }
                }
            } else if (which == -2) {// 取消
            } else if (which >= 0) {
                choicePostion = which;
            }
        }
    }
  
    /**
     * 执行任务
     * 
     * @author Administrator
     * 
     */
    private class ExecuteTask extends AsyncTask<Character,Void,Boolean> {
        @Override
        protected Boolean doInBackground(Character... params) {
            char c = params[0];
            if (c == 'B') {
                backUp();
            }
            return null;
        }
  
        @Override
        protected void onPostExecute(Boolean result) {
            super.onPostExecute(result);
            if (dialog != null) {
                dialog.dismiss();
            }
        }
    }
}
 

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