您的代码有问题，我已经测试了文件夹中空格的组合以及它正在工作的确切文件名。基于您的问题的工作代码 sn-p 如下，
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代码布局视图
build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.zackdawood.albummanager"
minSdkVersion 15
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}
字符串.xml
<resources>
<string name="app_name">AlbumManager</string>
<string name="write_button">Write Image</string>
<string name="read_button">Read Image</string>
<string name="request_access">Request Access</string>
</resources>
external_files.xml
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/>
</paths>
network_security_config.xml
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<domain-config cleartextTrafficPermitted="true">
<domain includeSubdomains="true">maven.apache.org</domain>
<domain includeSubdomains="true">upload.wikimedia.org</domain>
</domain-config>
</network-security-config>
GenericFileProvider.java
package com.zackdawood.albummanager;
import android.support.v4.content.FileProvider;
public class GenericFileProvider extends FileProvider {
}
FileDownloader.java
package com.zackdawood.albummanager;
import android.util.Log;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class FileDownloader {
private static final String TAG = "FileDownloader";
private static final int MEGABYTE = 1024 * 1024;
public static void downloadFile(String fileUrl, File directory) {
try {
Log.v(TAG, "downloadFile() invoked ");
Log.v(TAG, "downloadFile() fileUrl " + fileUrl);
Log.v(TAG, "downloadFile() directory " + directory);
URL url = new URL(fileUrl);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
InputStream inputStream = urlConnection.getInputStream();
FileOutputStream fileOutputStream = new FileOutputStream(directory);
int totalSize = urlConnection.getContentLength();
byte[] buffer = new byte[MEGABYTE];
int bufferLength = 0;
while ((bufferLength = inputStream.read(buffer)) > 0) {
fileOutputStream.write(buffer, 0, bufferLength);
}
fileOutputStream.close();
Log.v(TAG, "downloadFile() completed ");
} catch (FileNotFoundException e) {
e.printStackTrace();
Log.e(TAG, "downloadFile() error" + e.getMessage());
Log.e(TAG, "downloadFile() error" + e.getStackTrace());
} catch (MalformedURLException e) {
e.printStackTrace();
Log.e(TAG, "downloadFile() error" + e.getMessage());
Log.e(TAG, "downloadFile() error" + e.getStackTrace());
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "downloadFile() error" + e.getMessage());
Log.e(TAG, "downloadFile() error" + e.getStackTrace());
}
}
}
MainActivity.java
package com.zackdawood.albummanager;
import android.content.ActivityNotFoundException;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Toast;
import java.io.File;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private static final String[] PERMISSIONS = {android.Manifest.permission.READ_EXTERNAL_STORAGE,
android.Manifest.permission.WRITE_EXTERNAL_STORAGE,
android.Manifest.permission.INTERNET};
private static boolean hasPermissions(Context context, String... permissions) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && context != null && permissions != null) {
for (String permission : permissions) {
if (ActivityCompat.checkSelfPermission(context, permission) != PackageManager.PERMISSION_GRANTED) {
return false;
}
}
}
return true;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS, 112);
Log.v(TAG, "onCreate() Method invoked ");
}
public void write(View view) {
if (!hasPermissions(MainActivity.this, PERMISSIONS)) {
Log.v(TAG, "download() Method DON'T HAVE PERMISSIONS ");
Toast t = Toast.makeText(getApplicationContext(), "You don't have write access !", Toast.LENGTH_LONG);
t.show();
} else {
new DownloadFile().execute("https://upload.wikimedia.org/wikipedia/commons/thumb/c/c2/Adler.jpg/547px-Adler.jpg", "lab_result_2019-04-06.jpg");
}
}
public void read(View view) {
if (!hasPermissions(MainActivity.this, PERMISSIONS)) {
Log.v(TAG, "download() Method DON'T HAVE PERMISSIONS ");
Toast t = Toast.makeText(getApplicationContext(), "You don't have read access !", Toast.LENGTH_LONG);
t.show();
} else {
File folder = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
File directory = new File(folder + "/TB System");
File imgFile = new File(directory, "lab_result_2019-04-06.jpg");
Log.v(TAG, "view() Method imgfile " + imgFile.getAbsolutePath());
Uri path = FileProvider.getUriForFile(this, BuildConfig.APPLICATION_ID + ".fileprovider", imgFile);
Log.v(TAG, "view() Method path " + path);
Intent imageIntent = new Intent(Intent.ACTION_VIEW);
imageIntent.setDataAndType(path, "image/*");
imageIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
imageIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
try {
startActivity(imageIntent);
} catch (ActivityNotFoundException e) {
Toast.makeText(MainActivity.this, "No Application available to view Image", Toast.LENGTH_SHORT).show();
}
}
}
public void request(View view) {
ActivityCompat.requestPermissions(MainActivity.this, PERMISSIONS, 112);
}
private class DownloadFile extends AsyncTask<String, Void, Void> {
@Override
protected Void doInBackground(String... strings) {
Log.v(TAG, "doInBackground() Method invoked ");
String fileUrl = strings[0]; // -> http://maven.apache.org/maven-1.x/maven.pdf
String fileName = strings[1]; // -> maven.pdf
File folder = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
File directory = new File(folder + "/TB System");
if (!directory.exists()) {
directory.mkdir();
Log.v(TAG, "doInBackground() Method Directory Created ");
}
File imgFile = new File(directory, fileName);
Log.v(TAG, "doInBackground() imgFile invoked " + imgFile.getAbsolutePath());
Log.v(TAG, "doInBackground() imgFile invoked " + imgFile.getAbsoluteFile());
try {
imgFile.createNewFile();
Log.v(TAG, "doInBackground() file created" + imgFile);
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "doInBackground() error" + e.getMessage());
Log.e(TAG, "doInBackground() error" + e.getStackTrace());
}
FileDownloader.downloadFile(fileUrl, imgFile);
Log.v(TAG, "doInBackground() file download completed");
return null;
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="395dp"
android:layout_height="715dp"
android:orientation="vertical"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="8dp">
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/write_button"
android:onClick="write"/>
<Button
android:id="@+id/button3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/read_button"
android:onClick="read"/>
<Button
android:id="@+id/button4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/request_access"
android:onClick="request"/>
</LinearLayout>
</android.support.constraint.ConstraintLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.zackdawood.albummanager">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme"
android:networkSecurityConfig="@xml/network_security_config">
<provider
android:name=".GenericFileProvider"
android:authorities="${applicationId}.fileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/external_files"/>
</provider>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
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