我得到了
open failed: EACCES(权限被拒绝)
myOutput = new FileOutputStream(outFileName);
我检查了根目录，并尝试了android.permission.WRITE_EXTERNAL_STORAGE。
我该如何解决这个问题?
try {
InputStream myInput;
myInput = getAssets().open("XXX.db");
// Path to the just created empty db
String outFileName = "/data/data/XX/databases/"
+ "XXX.db";
// Open the empty db as the output stream
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();
buffer = null;
outFileName = null;
}
catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
对于API 23+，您需要请求读/写权限，即使它们已经在您的清单中。
// Storage Permissions
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
};
/**
* Checks if the app has permission to write to device storage
*
* If the app does not has permission then the user will be prompted to grant permissions
*
* @param activity
*/
public static void verifyStoragePermissions(Activity activity) {
// Check if we have write permission
int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (permission != PackageManager.PERMISSION_GRANTED) {
// We don't have permission so prompt the user
ActivityCompat.requestPermissions(
activity,
PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE
);
}
}
AndroidManifest.xml
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
有关请求API 23+权限的官方文档，请查看https://developer.android.com/training/permissions/requesting.html
添加gradle依赖项
implementation 'com.karumi:dexter:4.2.0'
在主活动中添加以下代码。
import com.karumi.dexter.Dexter;
import com.karumi.dexter.MultiplePermissionsReport;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.multi.MultiplePermissionsListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
checkMermission();
}
}, 4000);
}
private void checkMermission(){
Dexter.withActivity(this)
.withPermissions(
android.Manifest.permission.READ_EXTERNAL_STORAGE,
android.Manifest.permission.WRITE_EXTERNAL_STORAGE,
android.Manifest.permission.ACCESS_NETWORK_STATE,
Manifest.permission.INTERNET
).withListener(new MultiplePermissionsListener() {
@Override
public void onPermissionsChecked(MultiplePermissionsReport report) {
if (report.isAnyPermissionPermanentlyDenied()){
checkMermission();
} else if (report.areAllPermissionsGranted()){
// copy some things
} else {
checkMermission();
}
}
@Override
public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
token.continuePermissionRequest();
}
}).check();
}
谷歌在Android Q上有一个新功能:外部存储的过滤视图。一个快速的修复方法是在AndroidManifest.xml文件中添加以下代码:
<manifest ... >
<!-- This attribute is "false" by default on apps targeting Android Q. -->
<application android:requestLegacyExternalStorage="true" ... >
...
</application>
</manifest>
你可以在这里阅读更多信息:https://developer.android.com/training/data-storage/use-cases
编辑:我开始得到反对票，因为这个答案是过时的安卓11。看到答案的同学请点击上面的链接阅读说明。
