2

我不确定这段代码有什么问题？它在 SD 卡中创建了一个文件，但为 0 字节。你们中的一个可以查看它并告诉我这有什么问题吗？

在这里，我试图从资产文件夹中复制一个文件，即代码.db 到 sd 卡。

    AssetManager assetManager = getResources().getAssets();
    InputStream in = null;

    OutputStream out = null;
    BufferedInputStream buf = null;
    try {
        in = assetManager.open("codes.db");

    } catch (IOException e) {
        // TODO Auto-generated catch block
        System.out.println("Error jh: " + e.getMessage());
    }
    if (in != null) {
        try {
            out = new FileOutputStream("/sdcard/" + "codes.db");
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            System.out.println("Error Line : " + e.getLocalizedMessage());
        }
    }

    System.out.println("IN VALUE : " + in);
    System.out.println("OUT VALUE : " + out);


    int chunkBytes = 0;
    byte[] outputByte = new byte[1024];

    if (in != null && out != null) {
        try {

            // while ((chunkBytes = in.read(outputByte, 0, 1024)) != -1) {
            while ((chunkBytes = in.read()) != -1) {
                // write contents to the file
                System.out.println("I m here");
                // out.write(outputByte, 0, (int) chunkBytes);
                out.write(chunkBytes);
                // publish the progress of downloading..
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            System.out.println("Error here: "
                    + e.getLocalizedMessage().toString());
        }
    }

    try {
        in.close();
        out.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        System.out.println("Error there: " + e.getLocalizedMessage());
    }

}

在所有情况下我都会收到此错误..我确定我设置了权限...sd卡中的code.db是0字节... :(

05-24 09:59:34.221: W/System.err(5559): java.io.IOException
05-24 09:59:34.221: W/System.err(5559):     at android.content.res.AssetManager.readAsset(Native Method)
05-24 09:59:34.221: W/System.err(5559):     at android.content.res.AssetManager.access$700(AssetManager.java:36)
05-24 09:59:34.221: W/System.err(5559):     at android.content.res.AssetManager$AssetInputStream.read(AssetManager.java:571)
05-24 09:59:34.221: W/System.err(5559):     at com.bewo.copy.TestCopyActivity.copyStream(TestCopyActivity.java:136)
05-24 09:59:34.221: W/System.err(5559):     at com.bewo.copy.TestCopyActivity.onCreate(TestCopyActivity.java:19)
05-24 09:59:34.221: W/System.err(5559):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-24 09:59:34.221: W/System.err(5559):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2635)
05-24 09:59:34.221: W/System.err(5559):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2687)
05-24 09:59:34.221: W/System.err(5559):     at android.app.ActivityThread.access$2300(ActivityThread.java:127)
05-24 09:59:34.221: W/System.err(5559):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2035)
05-24 09:59:34.221: W/System.err(5559):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-24 09:59:34.221: W/System.err(5559):     at android.os.Looper.loop(Looper.java:123)
05-24 09:59:34.221: W/System.err(5559):     at android.app.ActivityThread.main(ActivityThread.java:4635)
05-24 09:59:34.221: W/System.err(5559):     at java.lang.reflect.Method.invokeNative(Native Method)
05-24 09:59:34.221: W/System.err(5559):     at java.lang.reflect.Method.invoke(Method.java:521)
05-24 09:59:34.221: W/System.err(5559):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-24 09:59:34.221: W/System.err(5559):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-24 09:59:34.221: W/System.err(5559):     at dalvik.system.NativeStart.main(Native
4

4 回答 4

3

经过多次搜索，我只是想要一个稍后可以在线程中使用的方法，这是我用于我的应用程序的方法：

static public void copyFileFromAssets(Context context, String file, String dest) throws Exception 
{
    InputStream in = null;
    OutputStream fout = null;
    int count = 0;

    try
    {
        in = context.getAssets().open(file);
        fout = new FileOutputStream(new File(dest));

        byte data[] = new byte[1024];
        while ((count = in.read(data, 0, 1024)) != -1)
        {
            fout.write(data, 0, count);
        }
    }
    catch (Exception e) 
    {
        e.printStackTrace();
    }   
    finally
    {
        if (in != null)
        {
            try {
                in.close();
            } catch (IOException e) 
            {
            }
        }
        if (fout != null)
        {
            try {
                fout.close();
            } catch (IOException e) {
            }
        }
    }
}

请让我知道这可不可以帮你！

于 2013-03-17T03:50:46.300 回答
3

我希望下面的代码可以帮助你 -

package com.paresh.copyfileassetstoAssets;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.app.Activity;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;

public class CopyFileAssetsToSDCardActivity extends Activity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

       CopyAssets();
    }

    private void CopyAssets() {
        AssetManager assetManager = getAssets();
        String[] files = null;
        try {
            files = assetManager.list("Files");
        } catch (IOException e) {
            Log.e("tag", e.getMessage());
        }

        for(String filename : files) {
            System.out.println("File name => "+filename);
            InputStream in = null;
            OutputStream out = null;
            try {
              in = assetManager.open("Files/"+filename);   // if files resides inside the "Files" directory itself
              out = new FileOutputStream(Environment.getExternalStorageDirectory().toString() +"/" + filename);
              copyFile(in, out);
              in.close();
              in = null;
              out.flush();
              out.close();
              out = null;
            } catch(Exception e) {
                Log.e("tag", e.getMessage());
            }
        }
    }
    private void copyFile(InputStream in, OutputStream out) throws IOException {
        byte[] buffer = new byte[1024];
        int read;
        while((read = in.read(buffer)) != -1){
          out.write(buffer, 0, read);
        }
    }
}

将资产文件复制到 sdcard的最佳博客。并且，还要确保外部存储所需的权限

于 2012-05-24T04:28:22.097 回答
1

无论您使用什么，请尝试在 AVD 管理器中增加 SD 卡的大小。我希望它对你有帮助。

于 2012-05-24T04:22:20.390 回答
0

这是我在项目中使用的代码。我觉得对你有用

public static void copyAssets(Context context) {
    AssetManager assetManager = context.getAssets();
    String[] files = null;
    try {
        files = assetManager.list("");
    } catch (IOException e) {
        Log.e("tag", "Failed to get asset file list.", e);
    }
    if (files != null) for (String filename : files) {
        InputStream in = null;
        OutputStream out = null;
        try {
            in = assetManager.open(filename);

            out = new FileOutputStream(Environment.getExternalStorageDirectory()+"/www/openrap/" + filename);
            copyFile(in, out);
        } catch(IOException e) {
            Log.e("tag", "Failed to copy asset file: " + filename, e);
        }
        finally {
            if (in != null) {
                try {
                    in.close();
                    in = null;
                } catch (IOException e) {

                }
            }
            if (out != null) {
                try {
                    out.flush();
                    out.close();
                    out = null;
                } catch (IOException e) {

                }
            }
        }
    }
}

public static void copyFile(InputStream in, OutputStream out) throws IOException {
    byte[] buffer = new byte[1024];
    int read;
    while((read = in.read(buffer)) != -1){
        out.write(buffer, 0, read);
    }
}
于 2018-10-31T04:53:10.383 回答