Android基础类之Bundle

Bundle类是一个key-value对，“A mapping from String values to various Parcelable types.”

1. 声明Bundle对象实例，压入键值对，并传递对象实例：

　　/**
     * Indicate that the connection was lost and notify the UI Activity.
     */
    private void connectionLost() {
        // Send a failure message back to the Activity
        Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(BluetoothChat.TOAST, "Device connection was lost");
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        // Start the service over to restart listening mode
        BluetoothChatService.this.start();
    }

2. 获取并解析Bundle对象实例：

　　// The Handler that gets information back from the BluetoothChatService
    private final Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
            case MESSAGE_STATE_CHANGE:
                if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1);
                switch (msg.arg1) {
                case BluetoothChatService.STATE_CONNECTED:
                    setStatus(getString(R.string.title_connected_to, mConnectedDeviceName));
                    mConversationArrayAdapter.clear();
                    break;
                case BluetoothChatService.STATE_CONNECTING:
                    setStatus(R.string.title_connecting);
                    break;
                case BluetoothChatService.STATE_LISTEN:
                case BluetoothChatService.STATE_NONE:
                    setStatus(R.string.title_not_connected);
                    break;
                }
                break;
            case MESSAGE_WRITE:
                byte[] writeBuf = (byte[]) msg.obj;
                // construct a string from the buffer
                String writeMessage = new String(writeBuf);
                mConversationArrayAdapter.add("Me:  " + writeMessage);
                break;
            case MESSAGE_READ:
                byte[] readBuf = (byte[]) msg.obj;
                // construct a string from the valid bytes in the buffer
                String readMessage = new String(readBuf, 0, msg.arg1);
                mConversationArrayAdapter.add(mConnectedDeviceName+":  " + readMessage);
                break;
            case MESSAGE_DEVICE_NAME:
                // save the connected device's name
                mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);
                Toast.makeText(getApplicationContext(), "Connected to "
                               + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                break;
            case MESSAGE_TOAST:
                Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST),
                               Toast.LENGTH_SHORT).show();
                break;
            }
        }
    };