在我的应用程序中,我必须使用许多视频文件。所有视频的总大小大约为 500 MB。因此,我必须在第一次安装和运行应用程序时决定我在后台下载视频,并在加密该视频后将其保存到设备的 SD 卡上。当使用视频时,我会解密该视频并使用它。
我决定这样做是因为所有视频文件都非常重要,因此该文件的安全性非常重要。
我非常努力地寻找如何加密视频并将其保存到 SD 卡...
最后我发现我把一件事放在下面,但在此代码中发生了权限被拒绝的错误。
Code:
public class VideoActivity extends Activity
{
VideoView video_view;
MediaController m_controller;
MediaPlayer mplayer;
String[] a = {"1","2","3","4","5","6"};
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
main(a);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void writeToFile(String filename, Object object) throws Exception
{
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try
{
fos = new FileOutputStream(new File(Environment.getExternalStorageDirectory()+"/corebird1.mp4"));
oos = new ObjectOutputStream(fos);
oos.writeObject(object);
oos.flush();
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
if (oos != null)
{
oos.close();
}
if (fos != null)
{
fos.close();
}
}
}
public void main(String[] args) throws Exception
{
//
// Generating a temporary key and stire it in a file.
//
SecretKey key = KeyGenerator.getInstance("DES").generateKey();
writeToFile("secretkey.dat", key);
Log.d("#######key", String.valueOf(key));
//
// Preparing Cipher object for encryption.
//
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key);
//
// Here we seal (encrypt) a simple string message (a string object).
//
SealedObject sealedObject = new SealedObject("THIS IS A SECRET MESSAGE!", cipher);
//
// Write the object out as a binary file.
//
writeToFile("sealed.dat", sealedObject);
}
}
LogCat:
08-10 12:22:32.430: WARN/System.err(338): java.io.FileNotFoundException: /mnt/sdcard/corebird1.mp4 (Permission denied)
08-10 12:22:32.430: WARN/System.err(338): at org.apache.harmony.luni.platform.OSFileSystem.openImpl(Native Method)
08-10 12:22:32.459: WARN/System.err(338): at org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:152)
08-10 12:22:32.459: WARN/System.err(338): at java.io.FileOutputStream.<init>(FileOutputStream.java:97)
08-10 12:22:32.459: WARN/System.err(338): at java.io.FileOutputStream.<init>(FileOutputStream.java:69)
08-10 12:22:32.459: WARN/System.err(338): at com.technosoft.video.VideoActivity.writeToFile(VideoActivity.java:71)
08-10 12:22:32.459: WARN/System.err(338): at com.technosoft.video.VideoActivity.main(VideoActivity.java:99)
08-10 12:22:32.459: WARN/System.err(338): at com.technosoft.video.VideoActivity.onCreate(VideoActivity.java:54)
08-10 12:22:32.459: WARN/System.err(338): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-10 12:22:32.459: WARN/System.err(338): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-10 12:22:32.459: WARN/System.err(338): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-10 12:22:32.470: WARN/System.err(338): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-10 12:22:32.470: WARN/System.err(338): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-10 12:22:32.470: WARN/System.err(338): at android.os.Handler.dispatchMessage(Handler.java:99)
08-10 12:22:32.470: WARN/System.err(338): at android.os.Looper.loop(Looper.java:123)
08-10 12:22:32.470: WARN/System.err(338): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-10 12:22:32.470: WARN/System.err(338): at java.lang.reflect.Method.invokeNative(Native Method)
08-10 12:22:32.470: WARN/System.err(338): at java.lang.reflect.Method.invoke(Method.java:521)
08-10 12:22:32.480: WARN/System.err(338): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-10 12:22:32.480: WARN/System.err(338): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-10 12:22:32.480: WARN/System.err(338): at dalvik.system.NativeStart.main(Native Method)
08-10 12:22:32.480: DEBUG/#######key(338): javax.crypto.spec.SecretKeySpec@69
08-10 12:22:32.510: WARN/System.err(338): java.io.FileNotFoundException: /mnt/sdcard/corebird1.mp4 (Permission denied)
08-10 12:22:32.510: WARN/System.err(338): at org.apache.harmony.luni.platform.OSFileSystem.openImpl(Native Method)
08-10 12:22:32.520: WARN/System.err(338): at org.apache.harmony.luni.platform.OSFileSystem.open(OSFileSystem.java:152)
08-10 12:22:32.520: WARN/System.err(338): at java.io.FileOutputStream.<init>(FileOutputStream.java:97)
08-10 12:22:32.520: WARN/System.err(338): at java.io.FileOutputStream.<init>(FileOutputStream.java:69)
08-10 12:22:32.520: WARN/System.err(338): at com.technosoft.video.VideoActivity.writeToFile(VideoActivity.java:71)
08-10 12:22:32.520: WARN/System.err(338): at com.technosoft.video.VideoActivity.main(VideoActivity.java:116)
08-10 12:22:32.520: WARN/System.err(338): at com.technosoft.video.VideoActivity.onCreate(VideoActivity.java:54)
08-10 12:22:32.520: WARN/System.err(338): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-10 12:22:32.520: WARN/System.err(338): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-10 12:22:32.520: WARN/System.err(338): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-10 12:22:32.520: WARN/System.err(338): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
08-10 12:22:32.520: WARN/System.err(338): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
08-10 12:22:32.520: WARN/System.err(338): at android.os.Handler.dispatchMessage(Handler.java:99)
08-10 12:22:32.520: WARN/System.err(338): at android.os.Looper.loop(Looper.java:123)
08-10 12:22:32.520: WARN/System.err(338): at android.app.ActivityThread.main(ActivityThread.java:4627)
08-10 12:22:32.520: WARN/System.err(338): at java.lang.reflect.Method.invokeNative(Native Method)
08-10 12:22:32.520: WARN/System.err(338): at java.lang.reflect.Method.invoke(Method.java:521)
08-10 12:22:32.530: WARN/System.err(338): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-10 12:22:32.530: WARN/System.err(338): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-10 12:22:32.530: WARN/System.err(338): at dalvik.system.NativeStart.main(Native Method)
任何机构都可以解决此错误,然后请帮助我......
或者如果您有任何其他解决方案或建议,那么您也可以提供帮助...我对此表示感谢...
我还想要解密编码视频并播放 android 的方法。
任何身体都有其他