这个异常只会在android 7.0 + 出现，当app使用file:// url 共享给其他app时， 会抛出这个异常。
因为在android 6.0 + 权限需要 在运行时候检查， 其他app 可能没有读写文件的权限， 所以google在7.0的时候加上了这个限制。
官方推荐使用 FileProvider 解决这个问题。
下面我们来看看具体实现步骤。
在manifest.xml文件添加provider，相机，读写文件权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.CAMERA"/>
<application>
...
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="com.example.android.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths"></meta-data>
</provider>
...
</application>
注意 android:authorities 里面的值，在后面使用的getUriForFile(Context, String, File) 中， 第二个参数就是这个里面的值。
编写file_paths.xml
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="my_images" path="images/"/>
</paths>
paths里面文件的一些可配置选项
<files-path name="name" path="path" /> //相当 Context.getFilesDir() + path, name是分享url的一部分
<cache-path name="name" path="path" /> //getCacheDir()
<external-path name="name" path="path" /> //Environment.getExternalStorageDirectory()
<external-files-path name="name" path="path" />//getExternalFilesDir(String) Context.getExternalFilesDir(null)
<external-cache-path name="name" path="path" /> //Context.getExternalCacheDir()
编写相机获取图片activity ： FileProviderActivity
package eebochina.com.testtechniques.fileProvider;
import android.Manifest;
import android.app.Activity;
import android.content.ClipData;
import android.content.ContentResolver;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.os.ParcelFileDescriptor;
import android.provider.MediaStore;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileNotFoundException;
import java.util.List;
import eebochina.com.testtechniques.R;
public class FileProviderActivity extends AppCompatActivity {
private Button mButton;
private ImageView mImageView;
private Uri contentUri;
private File newFile;
private Activity activity;
private final int NEED_CAMERA = 200;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file_provider);
activity = this;
mButton = (Button) findViewById(R.id.file_btn);
mImageView = (ImageView) findViewById(R.id.file_show);
mButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//检测是否有相机和读写文件权限
if (ContextCompat.checkSelfPermission(activity, Manifest.permission.CAMERA)
!= PackageManager.PERMISSION_GRANTED
|| ContextCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
activity.requestPermissions(new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, NEED_CAMERA);
} else {
startCamera();
}
}
});
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions,
int[] grantResults) {
switch (requestCode) {
case NEED_CAMERA:
// 如果权限被拒绝，grantResults 为空
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
startCamera();
} else {
Toast.makeText(activity, "改功能需要相机和读写文件权限", Toast.LENGTH_SHORT).show();
}
break;
}
}
/**
* 打开相机获取图片
*/
private void startCamera() {
File imagePath = new File(Environment.getExternalStorageDirectory(), "images");
if (!imagePath.exists()) imagePath.mkdirs();
newFile = new File(imagePath, "default_image.jpg");
//第二参数是在manifest.xml定义 provider的authorities属性
contentUri = FileProvider.getUriForFile(this, "com.example.android.fileprovider", newFile);
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
//兼容版本处理，因为 intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION) 只在5.0以上的版本有效
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
ClipData clip =
ClipData.newUri(getContentResolver(), "A photo", contentUri);
intent.setClipData(clip);
intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
} else {
List<ResolveInfo> resInfoList =
getPackageManager()
.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
for (ResolveInfo resolveInfo : resInfoList) {
String packageName = resolveInfo.activityInfo.packageName;
grantUriPermission(packageName, contentUri,
Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
}
}
intent.putExtra(MediaStore.EXTRA_OUTPUT, contentUri);
startActivityForResult(intent, 1000);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
ContentResolver contentProvider = getContentResolver();
ParcelFileDescriptor mInputPFD;
try {
//获取contentProvider图片
mInputPFD = contentProvider.openFileDescriptor(contentUri, "r");
FileDescriptor fileDescriptor = mInputPFD.getFileDescriptor();
mImageView.setImageBitmap(BitmapFactory.decodeFileDescriptor(fileDescriptor));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
}
代码已经写完，简陋的效果图附上：
FileProvider_img
欢迎大家提供更好的建议和解决方案！~
