Working with BLE Android 4.3 how to write characteristics?

Question

I am working on a BLE project (Android application) using Android 4.3 API, i have used sample BLE app it is only reading characteristics in DeviceControlActivity.activity, but i want to write characteristics and send it to BLE chip on clicking a button. How can I write data on chip cc2540 .. Basically i don't know the step by step procedure to write characteristics. write i can only see the name and id of device with following piece of code in DeviceControlActivity ``` private final ExpandableListView.OnChildClickListener servicesListClickListner = new ExpandableListView.OnChildClickListener() { @Override public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { if (mGattCharacteristics != null) { final BluetoothGattCharacteristic characteristic = mGattCharacteristics.get(groupPosition).get(childPosition); final int charaProp = characteristic.getProperties(); if ((charaProp | BluetoothGattCharacteristic.PROPERTY_READ) > 0) { // If…

Accepted Answer

The following code is write characteristic using `byte[]` data:

```
    public boolean writeCharacteristic(){

//check mBluetoothGatt is available
    if (mBluetoothGatt == null) {
        Log.e(TAG, "lost connection");
        return false;
    }
    BluetoothGattService Service = mBluetoothGatt.getService(your Services);
    if (Service == null) {
        Log.e(TAG, "service not found!");
        return false;
    }
    BluetoothGattCharacteristic charac = Service
            .getCharacteristic(your characteristic);
    if (charac == null) {
        Log.e(TAG, "char not found!");
        return false;
    }

byte[] value = new byte[1];
    value[0] = (byte) (21 & 0xFF);
    charac.setValue(value);
    boolean status = mBluetoothGatt.writeCharacteristic(charac);
    return status;
}
```

Working with BLE Android 4.3 how to write characteristics?

Solution

Problem