在创建手电筒应用程序中请求获得棉花糖许可

Question

我创建了一个手电筒应用程序。它适用于除棉花糖之外的所有设备。即使在我使用了请求许可之后。我觉得在要求获得我的代码许可时出现了问题。你有没有看到任何问题？

package com.funny.flashlight; 

import android.Manifest; 
import android.content.DialogInterface; 
import android.content.pm.PackageManager; 
import android.hardware.Camera; 
import android.support.annotation.NonNull; 
import android.support.v4.app.ActivityCompat; 
import android.support.v4.content.ContextCompat; 
import android.support.v7.app.AlertDialog; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.ImageButton; 
import android.widget.Toast; 

public class MainActivity extends AppCompatActivity 
{ 
    private static final int REQUEST_CAMERA = 0; 
    ImageButton imageButton; 
    Camera camera; 
    Camera.Parameters parameters; 
    boolean isflash=false; 
    boolean isOn=false; 

    public void showCamera(View view) 
    { 
       if(checkSelfPermission(Manifest.permission.CAMERA)==PackageManager.PERMISSION_GRANTED) 
     { 
      showCameraPreview(); 
     } 
     else 
     { 
      if (shouldShowRequestPermissionRationale(Manifest.permission.CAMERA)) 
      { 
       Toast.makeText(this, "Camera Permission is needed to show Camera Preview",Toast.LENGTH_SHORT).show(); 
      } 
      requestPermissions(new String[]{Manifest.permission.CAMERA},REQUEST_CAMERA); 
     } 

    } 


    @Override 
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 
     if (requestCode==REQUEST_CAMERA) 
     { 
      if (grantResults[0]==PackageManager.PERMISSION_GRANTED) 
      { 
       showCameraPreview(); 
      } 
      else { 
       Toast.makeText(this, "Permission was not Granted", Toast.LENGTH_SHORT).show(); 
      } 
     } 
     else { 
      super.onRequestPermissionsResult(requestCode, permissions, grantResults); 
     } 
    } 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     imageButton = (ImageButton) findViewById(R.id.imageButton); 
     if (getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)) 
     { 
      camera = Camera.open(); 
      parameters = camera.getParameters(); 
      isflash = true; 

     } 


    imageButton.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) 
      { 
       if (isflash) 
       { 
        if (isOn) 
        { 
         imageButton.setImageResource(R.drawable.off); 
         parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF); 
         camera.setParameters(parameters); 
         camera.stopPreview(); 
         isOn = false; 
        } 
        else 
        { 

         imageButton.setImageResource(R.drawable.on); 
         parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH); 
         camera.setParameters(parameters); 
         camera.startPreview(); 
         isOn = true; 
        } 

       } 
       else 
       { 
        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); 
        builder.setTitle("Error"); 
        builder.setMessage("FlashLight is not Available on this device"); 
        builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() { 
         @Override 
         public void onClick(DialogInterface dialog, int which) { 
          dialog.dismiss(); 
          finish(); 
         } 
        }); 
        AlertDialog alertDialog = builder.create(); 
        alertDialog.show(); 

       } 
      } 
     }); 
    } 

    @Override 
    protected void onStop() 
    { 
     super.onStop(); 
     if(camera!=null) 
     { 
      camera.release(); 
      camera=null; 
     } 
    } 

} 

Answer 1

取决于你想要做什么，我建议以下格式检查/请求权限：

private int CAMERA_PERM = 0; 


    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { 
      ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, CAMERA_PERM); 
    } 

然后检索响应：

@Override 
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) { 
     switch (requestCode) { 
      case CAMERA_PERM: { 
       // If request is cancelled, the result arrays are empty. 
       if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
        //Permission Granted 
       } else { 
        //Permission Denied 
       } 
       return; 
      } 
     } 
    }