android - 如何检查用户是否在运行时在 Android 上授予了权限？

Question

我创建了一个简单的 android Activity ，它充当拨号盘。 它有一个电话号码的编辑文本和一个调用按钮 这是代码:(android 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){
            }
        }
    });
}

当我运行我的应用程序时，我遇到了这些问题

• 如果我单击调用按钮并授予权限，则在我再次单击之前不会调用 Intent

• 我不知道如何检查权限是否被授予

Answer 1

使用 onRequestPermissionResult，如果用户按下 ALLOW 和 DENY，它会处理操作，只需在“如果用户按下允许”的条件下调用 Intent :

@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;
            }
        }
    }

希望这对您有所帮助。