Question

我正在学习如何在Android上使用蓝牙，我为//main.qml Rectangle{ id: root property point dragStart signal moved(point offset) MouseArea{ id: dragArea anchors.fill: parent onPressed: root.dragStart = Qt.point(dragArea.mouseX,dragArea.mouseY) onMouseXChanged: move() onMouseYChanged: move() function move(){ var offset = Qt.point(dragArea.mouseX-root.dragStart.x, dragArea.mouseY-root.dragStart.y) root.moved(offset) console.log(offset) } } } //MainWindow.cpp void MainWindow::moveQml(QPointF offset){ ui->quickWidget->move(ui->quickWidget->pos()+offset.toPoint()); }注册了BroadCastReceiver。在文档中，它说

广播操作：本地蓝牙适配器的状态已更改。      例如，蓝牙已打开或关闭。      始终包含额外字段EXTRA_STATE和EXTRA_PREVIOUS_STATE
     分别包含新旧州。

现在，我如何使用EXTRA_STATE和EXTRA_PREVIOUS_STATE？

Answer 1

来自here：

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
    final String action = intent.getAction();

    if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
        final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
                                             BluetoothAdapter.ERROR);
        switch (state) {
        case BluetoothAdapter.STATE_OFF:
            //Bluetooth off
            break;
        case BluetoothAdapter.STATE_TURNING_OFF:
            //Turning Bluetooth off...
            break;
        case BluetoothAdapter.STATE_ON:
            //Bluetooth on
            break;
        case BluetoothAdapter.STATE_TURNING_ON:
            //Turning Bluetooth on...
            break;
        }
    }
}

};

如何使用意图中的额外内容

1 个答案: