Question

我正在尝试使用BluetoothAdapter BA Intent方法将putExtra(String str, Bundle bundle)传递给另一个活动，但我的Android工作室的编译器显示错误。当我将鼠标悬停在方法下出现的红色曲线上时，它会显示我

Can't resolve method 'putExtra(java.lang.String, android.bluetooth.BluetoothAdapter)'

这就是我所说的

如果我理解正确，Bundle基本上是任何对象，因此通过putExtra将BluetoothAdapter传递给另一个活动不会有任何问题。

这是我的 MainActivity.java

package vertex2016.mvjce.edu.bluealert;

import android.bluetooth.BluetoothAdapter;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import static java.lang.Thread.sleep;

public class MainActivity extends AppCompatActivity {

    public BluetoothAdapter BA = BluetoothAdapter.getDefaultAdapter();
    private int REQ_CODE = 1;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    public void connect(View v)
    {
        if(BA == null)
            Toast.makeText(MainActivity.this, "System Doesn't Support Bluetooth", Toast.LENGTH_SHORT).show();

        else if(!BA.isEnabled())
        {
            Intent enableBT = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBT, REQ_CODE);
        }
        else {
            Toast.makeText(MainActivity.this, "ALREADY ON!!", Toast.LENGTH_SHORT).show();
            searchBTDevices();
        }
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(resultCode!=RESULT_CANCELED) {
            Toast.makeText(MainActivity.this, "TURNED ON!", Toast.LENGTH_SHORT).show();
            searchBTDevices();
        }
        else
            Toast.makeText(MainActivity.this,"FAILED TO ENABLE BLUETOOTH", Toast.LENGTH_LONG).show();
    }




    public void searchBTDevices()
    {
        Thread searchThread = new Thread() {
            @Override
            public void run() {
                Intent searchBT = new Intent(getApplicationContext(), SearchBTDevice.class);
                searchBT.putExtra("BT_ADAPTER", BA);
                startActivity(searchBT);
            }
        };
        searchThread.start();
    }
}

这是我应该收到额外信息的 SearchBTDevices.java 。

package vertex2016.mvjce.edu.bluealert;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;

public class SearchBTDevice extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search_btdevice);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

}

我哪里错了？

感谢您的时间!!

Answer 1

Intent只能用于传递基元Parcelable和Serializable对象。 BluetoothAdapter不支持其中任何一项，也无法使用原语构建，因此您无法创建可帮助您的Parcelable。

因此，当遇到这种情况时，您需要传入Activty可用于重新构建或检索执行所需对象的参数。

如果您需要能够使用不同的BluetoothAdapter，那么您需要告诉SearchBTDevices要检查哪个BluetoothAdapter并让SearchBTDevices检索适配器本身。例如，

public class SearchBTDevices extends Activity {
   public static final String PARAM_ADAPTER_TYPE = "adapterType";
   public static final int ADAPTER_DEFAULT = 1;
   public static final int ADAPTER_ALTERNATE = 2;

   private BluetoothAdapter mAdapter;

   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);

      int adapterType = getIntent().getIntExtra(PARAM_ADAPTER_TYPE, ADAPTER_DEFAULT);
      switch(adapterType) {
         case PARAM_ADAPTER_ALTERNATE:
             mAdapter = getAlternateAdapter(); // This is whatever method you need to get it.
             break;
         default:
             mAdapter = getDefaultAdapter();
      }
   }
}

现在，无论何时需要启动此活动，只需执行以下操作：

Intent intent = new Intent(getContext(), SearchBTDevices.class);
intent.putExtra(SearchBTDevices.PARAM_ADAPTER_TYPE, SearchBTDevices.ADAPTER_ALTERNATE);
startActivity(intent);

因此，当SearchBTDevices启动时，它将从intent中提取参数，并知道它需要使用备用适配器。

无法通过Intent的putExtra方法传递BluetoothAdapter对象

1 个答案: