我想创建一个简单的黑莓应用程序,每当我为手机充电时播放一个音频文件,并在我拔掉它时关闭应用程序。
伪代码
插入电池线后启动应用程序,
应用在充电时持续播放声音不能让它在中间没有间隙的情况下循环播放,而是播放声音
如果用户拔下电缆,停止流,播放声音,停止流
可选:如果电池电量下降到临界/完成充电,播放声音
通过查看文档,我认为没有听众告诉您电池电量是否为 100%。
编辑:找到了通过 batteryStatusChange 的方法,感谢 Nate 帮助我解决问题
有空异常错误。
编辑:使用了 InputStream 且不再出现空异常错误。将 wav 文件添加到 res 文件夹。下面的新代码播放 100 的声音和两种不同的声音,一种用于 USB 连接,另一种用于 USB 断开。
public class HelloBlackBerryScreen extends MainScreen implements SystemListener2 {
private BasicEditField basicEditField;
private Player HEV;
private String wav;
private InputStream stream;
private int volume; //going to set volume from GUI using a drop down list, working on it currently
public HelloBlackBerryScreen()
{
super( MainScreen.VERTICAL_SCROLL | MainScreen.VERTICAL_SCROLLBAR );
setTitle( "HelloBlackBerry" );
add(new RichTextField("Battery", RichTextField.TEXT_ALIGN_HCENTER));
Application.getApplication().addSystemListener(this);
wav = "voice_on.wav";
stream = (InputStream)this.getClass().getResourceAsStream("/" + wav);
try {
HEV = Manager.createPlayer(stream, "audio/wav");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (MediaException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void batteryGood() {
// TODO Auto-generated method stub
}
public void batteryLow() {
// TODO Auto-generated method stub
}
public void batteryStatusChange(int status)
{
// TODO Auto-generated method stub
if ((status & DeviceInfo.BSTAT_LEVEL_CHANGED) != 0)
{
if(DeviceInfo.getBatteryLevel() == 100)
{
try
{
setWav("power_level_is_100_percent.wav");
HEV.start();
stream.close();
}
catch (MediaException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
public void powerOff() {
// TODO Auto-generated method stub
}
public void powerUp() {
// TODO Auto-generated method stub
}
public void backlightStateChange(boolean on) {
// TODO Auto-generated method stub
}
public void cradleMismatch(boolean mismatch) {
// TODO Auto-generated method stub
}
public void fastReset() {
// TODO Auto-generated method stub
}
public void powerOffRequested(int reason) {
// TODO Auto-generated method stub
}
public void usbConnectionStateChange(int state)
{
// TODO Auto-generated method stub
if (state == USB_STATE_CABLE_CONNECTED)
{
try
{
setWav("suitchargeok1.wav");
HEV.start();
stream.close();
}
catch (MediaException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else if (state == USB_STATE_CABLE_DISCONNECTED)
{
try
{
stream.close();
setWav("battery_pickup.wav");
HEV.start();
stream.close();
} catch (MediaException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public String getWav() {
return wav;
}
public void setWav(String wav) {
this.wav = wav;
stream = (InputStream)this.getClass().getResourceAsStream("/" + this.wav);
try {
HEV = Manager.createPlayer(stream, "audio/wav");
HEV.realize();
VolumeControl volume = (VolumeControl) HEV.getControl("VolumeControl");
volume.setLevel(25);
HEV.prefetch();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (MediaException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public boolean onClose()
{
UiApplication.getUiApplication().requestBackground();
return true;
}
最佳答案
我需要更清楚地说明您希望该应用程序如何工作(请参阅我在您的问题下方的评论),但我很确定您将需要实现 SystemListener
(实际上是 SystemListener2
,是一种 SystemListener
)来监听 USB 状态变化。
像这样检测连接:
void usbConnectionStateChange(int state) {
if (state == USB_STATE_CABLE_CONNECTED) {
// start playing your sound
} else if (state == USB_STATE_CABLE_DISCONNECTED) {
// stop playing your sound, and exit, or just stay in the background
}
}
Here is a link on how to add/register a System Listener on device startup
See this BlackBerry forums link on detecting USB connection
And the API docs on SystemListener2, too
更新: 因为我相信发帖者已经弄明白了(基于问题中的代码更新),public void batteryStatusChange(int status)
方法可能是更直接的回调在这里使用。不过,其他一切都是一样的,因为那只是 SystemListener
中的另一个回调。
关于java - 根据电池是否正在充电来启动和关闭应用程序,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12440396/