前言
经过上一篇的学习，大家学习到蓝牙的实战，这节课我们给大家分享Flutter调用原生API实现检测手机GPS状态和打开GPS;再打开GPS之后实现显示当地经纬度
准备工具
这套课程是采用Android Studio进行开发的。当前在此之前请准备好Flutter开发环境，我这里就不进行讲解了
实战开始
在lib/main.dart添加一个调用原生方法
///////////Flutter 调用原生 Start//////////////
static const MethodChannel methodChannel=
MethodChannel('samples.flutter.io/gps');
Future<void> _inspection()async{
String message;
message=await methodChannel.invokeMethod('inspectionGPS');
setState(() {
_message=message;
});
}
Future<void> _open()async{
await methodChannel.invokeMethod('openGPS');
}
Future<void> _getDate() async{
await methodChannel.invokeMethod('getDate');
}
//////// Flutter 调用原生 End ////////
底层原生编写------------接受Flutter调用，调用安卓原生API
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GeneratedPluginRegistrant.registerWith(this);
new MethodChannel(getFlutterView(), BLUETOOTH_CHANNEL).setMethodCallHandler(
new MethodChannel.MethodCallHandler() {
@Override
public void onMethodCall(MethodCall methodCall, MethodChannel.Result result) {
if (methodCall.method.equals("inspectionGPS")) {
boolean isOpen = isOPen();
if (isOpen) { //检测GPS是否开启
result.success("GPS已开启");
}
result.success("GPS未开启");
} else if (methodCall.method.equals("openGPS")) { //打开GPS
openGPSSettings(context);
} else if (methodCall.method.equals("getDate")) { //显示经纬度
initLocation();
}
}
}
);
}
检测GPS是否开启
private boolean isOPen() {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
gps = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
network = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
/**确认GPS是否开启**/
if (gps || network) {
return true;
}
return false;
}
打开GPS
private boolean checkGpsIsOpen() {
boolean isOpen;
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
isOpen = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
return isOpen;
}
private void openGPSSettings(Context context) {
if (checkGpsIsOpen()) {
Toast.makeText(this, "true", Toast.LENGTH_SHORT).show();
} else {
new AlertDialog.Builder(this).setTitle("open GPS")
.setMessage("go to open")
// 取消选项
.setNegativeButton("cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Toast.makeText(MainActivity.this, "close", Toast.LENGTH_SHORT).show();
// 关闭dialog
dialogInterface.dismiss();
}
})
// 确认选项
.setPositiveButton("setting", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
//跳转到手机原生设置页面
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivityForResult(intent, 1);
}
})
.setCancelable(false)
.show();
}
}
显示经纬度
@TargetApi(Build.VERSION_CODES.M)
private void initLocation() {
//设置间隔两秒获得一次GPS定位信息
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// Activity#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for Activity#requestPermissions for more details.
return;
}
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 8, new LocationListener() {
@Override
public void onLocationChanged(Location location) {
// 当GPS定位信息发生改变时，更新定位
localDate=updateShow(location);
System.out.println("1.返回来的"+localDate);
final AlertDialog.Builder normalDialog = new AlertDialog.Builder(MainActivity.this);
normalDialog.setTitle("地区的详细信息");
normalDialog.setMessage(localDate);
normalDialog.show();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@SuppressLint("MissingPermission")
@Override
public void onProviderEnabled(String provider) {
localDate=updateShow(locationManager.getLastKnownLocation(provider));
}
@Override
public void onProviderDisabled(String provider) {
localDate=updateShow(null);
}
});
}
//定义一个更新显示的方法
private String updateShow(Location location) {
if (location != null) {
StringBuilder sb = new StringBuilder();
sb.append("当前的位置信息：\n");
sb.append("经度：" + location.getLongitude() + "\n");
sb.append("纬度：" + location.getLatitude() + "\n");
sb.append("定位精度：" + location.getAccuracy() + "\n");
System.out.println(sb.toString());
return sb.toString();
}
return null;
}
下面就是进行简单的布局
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: new Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text('GPS状态:'),
Text(
_message
)
],
),
Padding(
padding: EdgeInsets.all(10.0),
child: Column(
children: <Widget>[
RaisedButton(
color: Colors.blue,
textColor: Colors.white,
child: Text('检查GPS状态'),
onPressed: _inspection,
),
RaisedButton(
color: Colors.blue,
textColor: Colors.white,
child: Text('开关GPS'),
onPressed: _open,
),
RaisedButton(
color: Colors.blue,
textColor: Colors.white,
child: Text('获取经纬度'),
onPressed: _getDate,
),
],
)
)
],
),
),
);
}
完整的代码已经传到我的github上面，大家可以到https://github.com/1144075799/flutter_GPS下载源码观看，可以的话，给一个star。这个项目还会继续完善下去…