Question

public class DeviceListActivity extends Activity {
private static final String TAG = "DeviceListActivity";
private static final boolean D = true;

// Return Intent extra
public static String EXTRA_DEVICE_ADDRESS = "device_address";


// Member fields
private BluetoothAdapter mBtAdapter;
private ArrayAdapter<String> mPairedDevicesArrayAdapter;
private ArrayAdapter<String> mNewDevicesArrayAdapter;
//private String[] deviceAddresses={"","","","","","",""};
private Button scanButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Setup the window
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    setContentView(R.layout.device_list);

    // Set result CANCELED incase the user backs out
    setResult(Activity.RESULT_CANCELED);

    // Initialize the button to perform device discovery
    scanButton = (Button) findViewById(R.id.button_scan);

    scanButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            doDiscovery();

            findViewById(R.id.layoutButton).setVisibility(View.GONE);
        }
    });
     // Initialize array adapters. One for already paired devices and
    // one for newly discovered devices
    mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this,  R.layout.device_name);
    mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);

    // Find and set up the ListView for paired devices
    ListView pairedListView = (ListView) findViewById(R.id.paired_devices);
    pairedListView.setAdapter(mPairedDevicesArrayAdapter);
    pairedListView.setOnItemClickListener(mDeviceClickListener);

    // Find and set up the ListView for newly discovered devices
    ListView newDevicesListView = (ListView) findViewById(R.id.new_devices);
    newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
    newDevicesListView.setOnItemClickListener(mDeviceClickListener);

    // Register for broadcasts when a device is discovered
    IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
    this.registerReceiver(mReceiver, filter);

    // Register for broadcasts when discovery has finished
    filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    this.registerReceiver(mReceiver, filter);

    // Get the local Bluetooth adapter
    mBtAdapter = BluetoothAdapter.getDefaultAdapter();

    // Get a set of currently paired devices
    Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();

    // If there are paired devices, add each one to the ArrayAdapter
    if (pairedDevices.size() > 0) {
        findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
        for (BluetoothDevice device : pairedDevices) {
            mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
        }
    } else {
        String noDevices = getResources().getText(R.string.none_paired).toString();
        mPairedDevicesArrayAdapter.add(noDevices);
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();

    // Make sure we're not doing discovery anymore
    if (mBtAdapter != null) {
        mBtAdapter.cancelDiscovery();
    }

    // Unregister broadcast listeners
    this.unregisterReceiver(mReceiver);
}

/**
 * Start device discover with the BluetoothAdapter
 */
private void doDiscovery() {
    if (D) Log.d(TAG, "doDiscovery()");

    // Indicate scanning in the title
    setProgressBarIndeterminateVisibility(true);
    setTitle(R.string.scanning);

    // Turn on sub-title for new devices
    findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);
    findViewById(R.id.layoutNewDevices).setVisibility(View.VISIBLE);

    // If we're already discovering, stop it
    if (mBtAdapter.isDiscovering()) {
        mBtAdapter.cancelDiscovery();
    }

    // Request discover from BluetoothAdapter
    mBtAdapter.startDiscovery();
}

// The on-click listener for all devices in the ListViews
private AdapterView.OnItemClickListener mDeviceClickListener = new AdapterView.OnItemClickListener() {
    public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
        // Cancel discovery because it's costly and we're about to connect
        // mBtAdapter.cancelDiscovery();

        // Get the device MAC address, which is the last 17 chars in the View
        String info = ((TextView) v).getText().toString();
        String address = info.substring(info.length() - 17);

        // Create the result Intent and include the MAC address
        Intent intent = new Intent();
        intent.putExtra(EXTRA_DEVICE_ADDRESS, address);

        Toast.makeText(getApplicationContext(), "Device Selected " + "-> " + address, Toast.LENGTH_SHORT).show();
        setResult(Activity.RESULT_OK, intent);              // Set result and finish this Activity

        finish();
    }

};

}

当我执行我的应用程序并按一个按钮时，APP崩溃错误是;那么问题是什么？

我认为问题出在ArrayAdapter上，但我不知道解决它的问题

你能帮帮我吗？谢谢！

java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView

Answer 1

下面：

mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this,  R.layout.device_name);
mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);

ArrayAdapter期望布局R.layout.device_name只是TextView（而不是TextView / Linear中包含的Relative / FrameLayout）。您可以使用此构造函数：

new ArrayAdapter<String>(this,  R.layout.device_name, R.id.my_textview_id)

引用ArrayAdapter的文档：

由任意对象数组支持的具体BaseAdapter。默认情况下，此类期望提供的资源ID引用单个TextView。如果要使用更复杂的布局，请使用也带有字段ID的构造函数。该字段id应引用较大布局资源中的TextView。

我的代码出了什么问题？

1 个答案: