写一个安卓手机 app 用NDK 扫描连接蓝牙设备然后发送数据
时间: 2024-04-02 08:33:37 浏览: 19
好的,这是一个相对复杂的任务,需要一定的编程经验和知识。以下是一个简单的步骤:
1. 确保你已经安装了NDK,并且你的开发环境支持NDK开发。
2. 创建一个新的Android项目,并在gradle文件中添加NDK支持。
3. 创建一个Java类,用于处理蓝牙连接和数据传输。
4. 在JNI(Java Native Interface)中编写C++代码,用于扫描蓝牙设备并发送数据。
5. 将C++代码编译为动态库,并将其链接到你的Java类中。
6. 在你的Android app中调用JNI函数,以扫描蓝牙设备并发送数据。
这些步骤只是一个简单的概述,具体的实现细节需要根据你的具体情况进行调整。如果你对Android开发和NDK有一定的经验,那么这个任务应该不会太难。如果你对其中的某些步骤感到困惑,可以多查阅一些相关的技术资料和文档,或者向更有经验的开发者寻求帮助。
相关问题
使用python写一个安卓app
要使用 Python 编写安卓应用程序,你可以使用 Kivy 框架。Kivy 是一个开源的 Python 应用程序开发框架,可以帮助你创建跨平台的移动应用程序,包括 Android、iOS 和 Windows。
以下是使用 Kivy 创建一个简单的安卓应用程序的步骤:
1. 安装 Kivy
使用 pip 命令安装 Kivy:
```bash
pip install kivy
```
2. 创建应用程序
创建一个名为 main.py 的 Python 文件,并在其中编写应用程序的代码。例如,以下代码创建一个简单的应用程序,显示一个标签和一个按钮:
```python
import kivy
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.button import Button
class MyApp(App):
def build(self):
label = Label(text="Hello, world!")
button = Button(text="Click me!")
return label, button
if __name__ == "__main__":
MyApp().run()
```
3. 构建 APK 文件
使用 Buildozer 工具将 Python 代码打包成 APK 文件。Buildozer 是一个开源的 Python 工具,可帮助你构建 Android 应用程序。
首先安装 Buildozer:
```bash
pip install buildozer
```
然后在应用程序目录中创建一个名为 buildozer.spec 的文件,其中包含应用程序的配置信息。以下是一个示例文件:
```ini
[app]
# (str) Title of your application
title = My Application
# (str) Package name
package.name = myapp
# (str) Package domain (needed for android/ios packaging)
package.domain = org.example.myapp
# (str) Source code where the main.py live
source.dir = .
# (list) Source files to include (let empty to include all the files)
source.include_exts = py,png,jpg,kv,atlas
# (list) Application requirements
# comma separated e.g. requirements = sqlite3,kivy
requirements = kivy
[buildozer]
# (int) Log level (0 = error only, 1 = info, 2 = debug (with command line option -v))
log_level = 1
# (str) Path to build artifact storage, absolute or relative to spec file
# build_dir = ./.buildozer
# (str) Path to build output (i.e. .apk, .ipa) storage
# bin_dir = ./bin
# (str) Path to build output for debug builds (.apk/.ipa)
# debug = ./bin
# (str) Path to build output for release builds (.apk/.ipa)
# release = ./bin
# (list) List of build dependencies (boost, openssl, etc.)
# depends =
# (str) Android NDK version to use
# android.ndk_version = 19b
# (int) Android SDK version to use
# android.sdk_version = 24
# (str) Python for android distribution to use
# python-for-android.branch = master
# (str) python-for-android git clone directory (if not specified, it will be automatically cloned from github)
# python-for-android.source_dir =
# (str) The Android arch to build for, choices: armeabi-v7a, arm64-v8a, x86, x86_64
# arch = armeabi-v7a
# (str) Sequence of toolchain to use, chooses the first one that exists.
# toolchain = gcc
# (str) NDK directory (if empty, it will be automatically downloaded.)
# android.ndk_path =
# (str) Android SDK directory (if empty, it will be automatically downloaded.)
# android.sdk_path =
# (str) ANT directory (if empty, it will be automatically downloaded.)
# android.ant_path =
# (str) android api to use
# android.api = 27
# (bool) Use --private data storage (True) or --dir public storage (False)
# android.private_storage = True
# (str) Android NDK directory (if empty, it will be automatically downloaded)
# android.ndk_path = /home/user/android/android-ndk-r19c
# (str) Android SDK directory (if empty, it will be automatically downloaded)
# android.sdk_path = /home/user/android/android-sdk-24
# (str) Build platform for python-for-android (ios, android, manylinux2010)
# p4a.build_platform = android
# (str) Path to a custom AndroidManifest.xml
# android.manifest =
# (str) Path to a custom source.properties
# android.source_properties =
# (str) Path to a custom ant.properties
# android.ant_properties =
# (str) Path to a custom androidtool.cfg
# android.androidtool_cfg =
# (str) Path to the android command to use.
# android.cmd = adb
```
最后,使用 Buildozer 命令打包 APK 文件:
```bash
buildozer android debug
```
4. 运行应用程序
在 Android 设备上安装 APK 文件,并启动应用程序。你应该可以看到一个显示标签和按钮的屏幕。
以上就是使用 Python 创建安卓应用程序的基本步骤。你可以在 Kivy 文档中找到更多相关信息。
请写一个使用NDK播放声音的例子
好的,以下是一个使用NDK播放声音的例子:
1. 首先,在Android Studio中创建一个新的NDK项目。
2. 在app / src / main / jni目录下创建一个名为audio.c的新文件。
3. 将以下代码复制并粘贴到audio.c文件中:
```c
#include <jni.h>
#include <string.h>
#include <android/log.h>
#include <SLES/OpenSLES.h>
#include <SLES/OpenSLES_Android.h>
#define TAG "AudioPlayer"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)
// 声明OpenSL ES接口
SLObjectItf engineObject = NULL;
SLEngineItf engineEngine;
SLObjectItf outputMixObject = NULL;
SLEnvironmentalReverbItf outputMixEnvironmentalReverb = NULL;
SLEnvironmentalReverbSettings reverbSettings = SL_I3DL2_ENVIRONMENT_PRESET_STONECORRIDOR;
SLObjectItf playerObject = NULL;
SLPlayItf playerPlay;
SLAndroidSimpleBufferQueueItf playerBufferQueue;
void playerCallback(SLAndroidSimpleBufferQueueItf bq, void *context) {
LOGI("playerCallback");
}
JNIEXPORT void JNICALL
Java_com_example_audioplayer_AudioPlayer_init(JNIEnv *env, jobject instance) {
LOGI("init");
// 创建OpenSL ES引擎
slCreateEngine(&engineObject, 0, NULL, 0, NULL, NULL);
(*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
(*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);
// 创建输出混音器
(*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 0, NULL, NULL);
(*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
(*outputMixObject)->GetInterface(outputMixObject, SL_IID_ENVIRONMENTALREVERB, &outputMixEnvironmentalReverb);
(*outputMixEnvironmentalReverb)->SetEnvironmentalReverbProperties(outputMixEnvironmentalReverb, &reverbSettings);
// 创建播放器
SLDataLocator_AndroidSimpleBufferQueue locatorBufferQueue = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 2};
SLDataFormat_PCM formatPcm = {SL_DATAFORMAT_PCM, 1, SL_SAMPLINGRATE_44_1,
SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16,
SL_SPEAKER_FRONT_CENTER, SL_BYTEORDER_LITTLEENDIAN};
SLDataSource audioSrc = {&locatorBufferQueue, &formatPcm};
SLDataLocator_OutputMix locatorOutputMix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};
SLDataSink audioSnk = {&locatorOutputMix, NULL};
const SLInterfaceID ids[1] = {SL_IID_BUFFERQUEUE};
const SLboolean req[1] = {SL_BOOLEAN_TRUE};
(*engineEngine)->CreateAudioPlayer(engineEngine, &playerObject, &audioSrc, &audioSnk, 1, ids, req);
(*playerObject)->Realize(playerObject, SL_BOOLEAN_FALSE);
(*playerObject)->GetInterface(playerObject, SL_IID_PLAY, &playerPlay);
(*playerObject)->GetInterface(playerObject, SL_IID_BUFFERQUEUE, &playerBufferQueue);
(*playerBufferQueue)->RegisterCallback(playerBufferQueue, playerCallback, NULL);
}
JNIEXPORT void JNICALL
Java_com_example_audioplayer_AudioPlayer_play(JNIEnv *env, jobject instance, jbyteArray data_, jint len) {
LOGI("play");
// 将数据写入缓冲区
jbyte *data = (*env)->GetByteArrayElements(env, data_, NULL);
(*playerBufferQueue)->Clear(playerBufferQueue);
(*playerBufferQueue)->Enqueue(playerBufferQueue, data, len);
(*env)->ReleaseByteArrayElements(env, data_, data, 0);
// 开始播放
(*playerPlay)->SetPlayState(playerPlay, SL_PLAYSTATE_PLAYING);
}
JNIEXPORT void JNICALL
Java_com_example_audioplayer_AudioPlayer_stop(JNIEnv *env, jobject instance) {
LOGI("stop");
// 停止播放
(*playerPlay)->SetPlayState(playerPlay, SL_PLAYSTATE_STOPPED);
// 销毁播放器
if (playerObject != NULL) {
(*playerObject)->Destroy(playerObject);
playerObject = NULL;
playerPlay = NULL;
playerBufferQueue = NULL;
}
// 销毁输出混音器
if (outputMixObject != NULL) {
(*outputMixObject)->Destroy(outputMixObject);
outputMixObject = NULL;
outputMixEnvironmentalReverb = NULL;
}
// 销毁OpenSL ES引擎
if (engineObject != NULL) {
(*engineObject)->Destroy(engineObject);
engineObject = NULL;
engineEngine = NULL;
}
}
```
4. 在app / src / main / java目录下创建一个名为AudioPlayer.java的新文件,并将以下代码复制并粘贴到其中:
```java
package com.example.audioplayer;
public class AudioPlayer {
static {
System.loadLibrary("audio");
}
public native void init();
public native void play(byte[] data, int len);
public native void stop();
}
```
5. 现在可以在您的应用程序中使用AudioPlayer类来播放声音了。在您的Android应用程序中,创建一个新的AudioPlayer对象并调用init方法来初始化OpenSL ES引擎。然后,使用play方法将PCM音频数据写入缓冲区并开始播放,使用stop方法停止播放并销毁OpenSL ES引擎。
这个例子可能还需要一些改进,比如添加错误处理和音频数据的缓冲等。但这应该可以帮助您入门使用NDK播放声音。