如何检查权限是否由运行时用户在Android上授予？

Question

我创建了一个简单的android活动，充当拨号。 它有一个电话号码和一个呼叫按钮 这里一个EditText是代码：（安卓6.0棉花糖）

public class Main2Activity extends AppCompatActivity { 
EditText num; 
Button call; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main2); 
    num = (EditText) findViewById(R.id.num); 
    call = (Button) findViewById(R.id.call); 
    call.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      try { 
       // request permission if not granted 
       if (ActivityCompat.checkSelfPermission(Main2Activity.this, Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) { 
        ActivityCompat.requestPermissions(Main2Activity.this, new String[]{Manifest.permission.CALL_PHONE}, 123); 
        // i suppose that the user has granted the permission 
        Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString())); 
        startActivity(in); 
       // if the permission is granted then ok 
       } else { 
        Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString())); 
        startActivity(in); 
       } 
      } 
      // catch the exception if i try to make a call and the permission is not granted 
      catch (Exception e){ 
      } 
     } 
    }); 
} 

}

当我跑我的应用程序，有问题

• 如果我点击通话按钮并授予权限，则意图不会被调用，直到我再次点击

• 我不知道如何o或检查的权限被授予不

Answer 1

使用onRequestPermissionResult，它处理的行动，如果用户按ALLOW和DENY，只需调用中的条件意图“如果用户按下允许”：

@Override 
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) { 
     super.onRequestPermissionsResult(requestCode, permissions, grantResults); 
     switch (requestCode) { 
      case 123: { 
       if (grantResults.length > 0 
         && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
        //If user presses allow 
        Toast.makeText(Main2Activity.this, "Permission granted!", Toast.LENGTH_SHORT).show(); 
        Intent in = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + num.getText().toString())); 
       startActivity(in); 
       } else { 
        //If user presses deny 
        Toast.makeText(Main2Activity.this, "Permission denied", Toast.LENGTH_SHORT).show(); 
       } 
       break; 
      } 
     } 
    } 

希望这会有所帮助。