diff --git a/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/BluetoothManager.java b/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/BluetoothManager.java
index 728dbd0..f7331fc 100644
--- a/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/BluetoothManager.java
+++ b/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/BluetoothManager.java
@@ -231,12 +231,16 @@ public void write(byte[] data) {
         }
     }
 
-//    public <T extends Object> void  write(T obj){
-//
-//        if (mBluetoothService != null){
-//
-//        }
-//    }
+    /**
+     * Send a file.
+     * @param path
+     * @param fileName
+     */
+    public void write(String path, String fileName){
+        if (mBluetoothService != null){
+            mBluetoothService.write(path, fileName);
+        }
+    }
 
     /**
      * Get UUID.
diff --git a/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/service/BluetoothService.java b/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/service/BluetoothService.java
index b2d8669..a65a8be 100644
--- a/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/service/BluetoothService.java
+++ b/lmbluetoothsdk/src/main/java/co/lujun/lmbluetoothsdk/service/BluetoothService.java
@@ -20,7 +20,10 @@
 import android.bluetooth.BluetoothDevice;
 import android.bluetooth.BluetoothServerSocket;
 import android.bluetooth.BluetoothSocket;
+import android.util.Log;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -188,7 +191,37 @@ public void write(byte[] out) {
             }
             r = mConnectedThread;
         }
-        r.write(out);
+        r.write(out, 0, out.length);
+    }
+
+    /**
+     * Write a file as bytes to the ConnectedThread in an unsynchronized manner.
+     * @param path
+     * @param fileName
+     */
+    public void write(final String path, final String fileName){
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+                ConnectedThread r;
+                synchronized (this) {
+                    if (mState != State.STATE_CONNECTED) {
+                        return;
+                    }
+                    r = mConnectedThread;
+                }
+                try {
+                    FileInputStream in = new FileInputStream(path + "/" + fileName);
+                    byte[] buffer = new byte[1024];
+                    int len;
+                    while ((len = in.read(buffer, 0, buffer.length)) != -1){
+                        r.write(buffer, 0, len);
+                    }
+                    in.close();
+                }catch (IOException e){}
+
+            }
+        }).start();
     }
 
     /**
@@ -326,9 +359,9 @@ public void run() {
          * Write to the connected OutStream.
          * @param buffer The bytes to write
          */
-        public void write(byte[] buffer) {
+        public void write(byte[] buffer, int start, int end) {
             try {
-                mmOutStream.write(buffer);
+                mmOutStream.write(buffer, start, end);
             } catch (IOException e) {}
         }
 
diff --git a/sample/src/main/AndroidManifest.xml b/sample/src/main/AndroidManifest.xml
index fd10496..5dabec1 100644
--- a/sample/src/main/AndroidManifest.xml
+++ b/sample/src/main/AndroidManifest.xml
@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="co.lujun.sample">
 
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
diff --git a/sample/src/main/java/co/lujun/sample/MainActivity.java b/sample/src/main/java/co/lujun/sample/MainActivity.java
index 276446b..3d6b597 100644
--- a/sample/src/main/java/co/lujun/sample/MainActivity.java
+++ b/sample/src/main/java/co/lujun/sample/MainActivity.java
@@ -2,25 +2,26 @@
 
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
 import android.os.Bundle;
-import android.support.design.widget.FloatingActionButton;
-import android.support.design.widget.Snackbar;
+import android.os.Environment;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
 import android.text.TextUtils;
 import android.util.Log;
 import android.view.View;
-import android.view.Menu;
-import android.view.MenuItem;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
 import android.widget.BaseAdapter;
 import android.widget.Button;
 import android.widget.EditText;
+import android.widget.ImageView;
 import android.widget.ListView;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
@@ -33,12 +34,12 @@ public class MainActivity extends AppCompatActivity {
 
     private BluetoothManager mBluetoothManager;
     
-    private Button btnScanAvaliabe, btnScan, btnSend, btnOpen, btnStartServer, btnDisconnect;
+    private Button btnScanAvaliabe, btnScan, btnSend, btnOpen, btnStartServer, btnDisconnect, btnSendFile;
     private TextView tvContent, tvConnectState, tvBTState;
     private EditText etSend;
     private ListView lvDevices;
+    private ImageView ivRec;
 
-    private List<BluetoothDevice> mDevicesList;
     private List<String> mList;
     private BaseAdapter mFoundAdapter;
     private int mConnectState;
@@ -92,7 +93,6 @@ public void run() {
 
             @Override
             public void onActionDeviceFound(BluetoothDevice device) {
-                mDevicesList.add(device);
                 mList.add(device.getName() + "@" + device.getAddress());
                 mFoundAdapter.notifyDataSetChanged();
             }
@@ -105,14 +105,18 @@ public void onReadData(final BluetoothDevice device, final byte[] data) {
                     public void run() {
                         String deviceName = device == null ? "" : device.getName();
                         tvContent.append(deviceName + ": " + new String(data) + "\n");
+                        Log.d("debugss", "" + data.length);
+                        if (data.length == 5331) {
+                            Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
+                            ivRec.setImageBitmap(bitmap);
+                        }
                     }
                 });
             }
         });
     }
-    
+    private byte[] bytes = new byte[5331];
     private void init(){
-        mDevicesList = new ArrayList<BluetoothDevice>();
         mList = new ArrayList<String>();
         mFoundAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mList);
         
@@ -122,11 +126,13 @@ private void init(){
         btnOpen = (Button) findViewById(R.id.btn_open_bt);
         btnStartServer = (Button) findViewById(R.id.btn_start_as_server);
         btnDisconnect = (Button) findViewById(R.id.btn_disconnect);
+        btnSendFile = (Button) findViewById(R.id.btn_send_file);
         tvContent = (TextView) findViewById(R.id.tv_chat_content);
         tvConnectState = (TextView) findViewById(R.id.tv_connect_state);
         tvBTState = (TextView) findViewById(R.id.tv_bt_state);
         etSend = (EditText) findViewById(R.id.et_send_content);
         lvDevices = (ListView) findViewById(R.id.lv_devices);
+        ivRec = (ImageView) findViewById(R.id.iv_rec);
 
         initBT();
 
@@ -146,6 +152,8 @@ public void onClick(View v) {
         btnScan.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
+                mList.clear();
+                mFoundAdapter.notifyDataSetChanged();
                 if(!mBluetoothManager.startScan()){
                     Toast.makeText(MainActivity.this, "Start scan failed!",
                             Toast.LENGTH_SHORT).show();
@@ -166,6 +174,12 @@ public void onClick(View v) {
                 tvContent.append("Me: " + msg + "\n");
             }
         });
+        btnSendFile.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                mBluetoothManager.write(Environment.getExternalStorageDirectory().getPath(), "1234321.png");
+            }
+        });
         btnOpen.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
diff --git a/sample/src/main/res/layout/content_main.xml b/sample/src/main/res/layout/content_main.xml
index 96bbf90..f733691 100644
--- a/sample/src/main/res/layout/content_main.xml
+++ b/sample/src/main/res/layout/content_main.xml
@@ -76,8 +76,8 @@
             android:layout_height="30dp"
             android:layout_weight="1"
             android:gravity="center"
-            android:textSize="10sp"
-            android:singleLine="true" />
+            android:singleLine="true"
+            android:textSize="10sp" />
 
         <TextView
             android:id="@+id/tv_connect_state"
@@ -85,8 +85,8 @@
             android:layout_height="30dp"
             android:layout_weight="1"
             android:gravity="center"
-            android:textSize="10sp"
-            android:singleLine="true" />
+            android:singleLine="true"
+            android:textSize="10sp" />
 
     </LinearLayout>
 
@@ -95,16 +95,30 @@
         android:layout_height="1dp"
         android:background="#666666" />
 
-    <ScrollView
+    <LinearLayout
         android:layout_width="match_parent"
-        android:layout_height="150dp">
+        android:layout_height="wrap_content"
+        android:orientation="horizontal">
 
-        <TextView
-            android:id="@+id/tv_chat_content"
+        <ScrollView
             android:layout_width="match_parent"
-            android:layout_height="match_parent" />
+            android:layout_height="150dp"
+            android:layout_weight="1">
+
+            <TextView
+                android:id="@+id/tv_chat_content"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent" />
 
-    </ScrollView>
+        </ScrollView>
+
+        <ImageView
+            android:id="@+id/iv_rec"
+            android:layout_width="match_parent"
+            android:layout_height="150dp"
+            android:layout_weight="1" />
+
+    </LinearLayout>
 
     <LinearLayout
         android:layout_width="match_parent"
@@ -124,5 +138,12 @@
             android:layout_weight="1"
             android:text="发送" />
 
+        <Button
+            android:id="@+id/btn_send_file"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="发送图片" />
+
     </LinearLayout>
 </LinearLayout>