在使用 Web 视图开发的应用程序中访问手机存储

Question

我已经使用webview将网站转换为应用程序，我需要从手机存储中访问图像和文件。我尝试添加READ_EXTERNAL_STORAGE和WRITE_EXTERNAL_STORAGE但它不起作用。 访问存储的按钮是浏览

这是我的MainActivity.java代码

import androidx.appcompat.app.AppCompatActivity;                      
import android.os.Bundle;                                                
import android.webkit.WebSettings;                                      
import android.webkit.WebView;                                        
import android.webkit.WebViewClient;                                       
         
public class MainActivity extends AppCompatActivity {                          
private WebView mywebview;                                                 
         
@Override                                                                  
protected void onCreate(Bundle savedInstanceState) {                       
super.onCreate(savedInstanceState);                                    
setContentView(R.layout.activity_main);                                
mywebview = (WebView) findViewById(R.id.webview);                      
WebSettings webSettings = mywebview.getSettings();                     
webSettings.setJavaScriptEnabled(true);                                
mywebview.loadUrl("https://www.google.com");                           
mywebview.setWebViewClient(new WebViewClient());                       
}                                                                          
         
@Override                                                                  
public void onBackPressed() {                                            
if (mywebview.canGoBack()) {                                            
mywebview.goBack();                                                
} else {                                                               
super.onBackPressed();                                             
}                                                                      
}                                                                          
}

AndroidManifest.xml文件在这里

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<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">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

请提出解决方案。

Answer 1

您应该考虑在开始时进行权限检查oncreate

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
isStoragePermissionGranted();
...
}
public  boolean isStoragePermissionGranted() {
if (Build.VERSION.SDK_INT >= 23) {
if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
== PackageManager.PERMISSION_GRANTED) {
Log.v(TAG,"Permission is granted");
return true;
} else {
Log.v(TAG,"Permission is revoked");
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
return false;
}
}
else { //permission is automatically granted on sdk<23 upon installation
Log.v(TAG,"Permission is granted");
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(grantResults[0]== PackageManager.PERMISSION_GRANTED){
Log.v(TAG,"Permission: "+permissions[0]+ "was "+grantResults[0]);
//resume tasks needing this permission
}
}