Java 如何将值存储在全局变量中,并在“活动”中任何位置的任何方法中使用它
我正在尝试构建一个天气应用程序。我有一个API链接,我把它作为字符串变量,它的作用域是全局的,我还有另一个方法,通过它我可以获得经度和纬度。我想将这些纬度和经度值保存在范围为全局的变量中。当我在我的geocoder方法中取出纬度和经度值时(我的全局变量API链接会发生变化,并给出所需的结果,因为我将longtiude和latitude与作用域为全局的变量连接在一起。但是一旦我退出此方法,并尝试以不同的方法使用我的API链接(我丢失了获得的纬度和经度值,并用geocoder方法连接起来,希望它能永久改变我的全局变量值 下面是代码。(我有4-5个文件,但我只在我实际工作的地方粘贴主要活动代码)如果我硬编码纬度和经度值,我会得到所需的结果,但我只是试图通过获得纬度和经度来提高这一点Java 如何将值存储在全局变量中,并在“活动”中任何位置的任何方法中使用它,java,android,variables,scope,Java,Android,Variables,Scope,我正在尝试构建一个天气应用程序。我有一个API链接,我把它作为字符串变量,它的作用域是全局的,我还有另一个方法,通过它我可以获得经度和纬度。我想将这些纬度和经度值保存在范围为全局的变量中。当我在我的geocoder方法中取出纬度和经度值时(我的全局变量API链接会发生变化,并给出所需的结果,因为我将longtiude和latitude与作用域为全局的变量连接在一起。但是一旦我退出此方法,并尝试以不同的方法使用我的API链接(我丢失了获得的纬度和经度值,并用geocoder方法连接起来,希望它能永
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<List<Model>> {
public static final int WEATHERLOADER = 1;
RecyclerView recyclerView;
WeatherAdapter mAdapter;
List<Model> modelList;
FusedLocationProviderClient fusedLocation;
String latitude;
String longit;
Button getweather;
String APILINK = "http://api.openweathermap.org/data/2.5/weather?lat=";
String APIKEY = "&appid=5c161192e5aa828fc6a8896eddaf89e2";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getweather = findViewById(R.id.getWeather);
recyclerView = findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
modelList = new ArrayList<>();
mAdapter = new WeatherAdapter(this, modelList);
recyclerView.setAdapter(mAdapter);
ConnectivityManager conn = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);
if (conn!=null) {
NetworkInfo networkInfo = conn.getActiveNetworkInfo();
if (networkInfo!=null){
LoaderManager loaderManager = getSupportLoaderManager();
loaderManager.initLoader(WEATHERLOADER, null, this);
}
}
fusedLocation = LocationServices.getFusedLocationProviderClient(this);
getweather.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ) {
wantLocation();
} else {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 44);
}
}
});
}
private void wantLocation() {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#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 ActivityCompat#requestPermissions for more details.
return;
}
fusedLocation.getLastLocation().addOnCompleteListener(new OnCompleteListener<Location>() {
@Override
public void onComplete(@NonNull Task<Location> task) {
Location location = task.getResult();
if (location != null) {
try {
Geocoder geocoder = new Geocoder(
MainActivity.this, Locale.getDefault());
List<Address> addresses = geocoder.getFromLocation(location.getLatitude(), location.getLongitude(), 1);
/*cityname.setText(Html.fromHtml("<font color='#6200EE'><b>City Name:</b><br></font>" + addresses.get(0).getAdminArea()));
longtitude.setText(Html.fromHtml("<font color='#6200EE'><b>Longtitude:</b><br></font>" + addresses.get(0).getLongitude()));
lattitude.setText(Html.fromHtml("<font color='#6200EE'><b>Lattitude:</b><br></font>" + addresses.get(0).getLatitude()));
countryname.setText(Html.fromHtml("<font color='#6200EE'><b>Country Name:</b><br></font>" + addresses.get(0).getCountryName()));
*/
APILINK = APILINK + addresses.get(0).getLatitude() + "&lon=" + addresses.get(0).getLongitude() + APIKEY;
} catch (IOException e) {
e.printStackTrace();
}
}
}
});
}
@NonNull
@Override
public Loader<List<Model>> onCreateLoader(int i, @Nullable Bundle bundle) {
Toast.makeText(MainActivity.this, String.valueOf(APILINK), Toast.LENGTH_SHORT).show();
return new WeatherLoader(this, APILINK);
}
@Override
public void onLoadFinished(@NonNull Loader<List<Model>> loader, List<Model> modelList) {
if (modelList!=null && !modelList.isEmpty()) {
mAdapter = new WeatherAdapter(this, modelList);
recyclerView.setAdapter(mAdapter);
}
}
@Override
public void onLoaderReset(@NonNull Loader<List<Model>> loader) {
}
}
public类MainActivity扩展AppCompatActivity实现LoaderManager.LoaderCallbacks{
公共静态最终int WEATHERLOADER=1;
回收视图回收视图;
天气适配器;
列表模型列表;
FusedLocationProviderClient fusedLocation;
弦纬度;
弦长;
天气预报;
字符串APILINK=”http://api.openweathermap.org/data/2.5/weather?lat=";
字符串APIKEY=“&appid=5c161192e5aa828fc6a8896eddaf89e2”;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getweather=findviewbyd(R.id.getweather);
recyclerView=findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(新的LinearLayoutManager(本));
modelList=新的ArrayList();
mAdapter=新的WeatherAdapter(此,型号列表);
recyclerView.setAdapter(mAdapter);
ConnectivityManager conn=(ConnectivityManager)getSystemService(CONNECTIVITY_服务);
如果(conn!=null){
NetworkInfo NetworkInfo=conn.getActiveNetworkInfo();
if(networkInfo!=null){
LoaderManager LoaderManager=getSupportLoaderManager();
initLoader(WEATHERLOADER,null,this);
}
}
fusedLocation=LocationServices.getFusedLocationProviderClient(此);
getweather.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
if(ActivityCompat.checkSelfPermission(MainActivity.this、Manifest.permission.ACCESS\u FINE\u LOCATION)==PackageManager.permission\u已授予){
wantLocation();
}否则{
ActivityCompat.requestPermissions(MainActivity.this,新字符串[]{Manifest.permission.ACCESS\u FINE\u LOCATION},44);
}
}
});
}
私有void wantLocation(){
if(ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS\u FINE\u LOCATION)!=PackageManager.permission\u已授予和&ActivityCompat.checkSelfPermission(this,Manifest.permission.ACCESS\u LOCATION)!=PackageManager.permission\u已授予){
考虑到呼叫
//ActivityCompat#请求权限
//在此处请求缺少的权限,然后覆盖
//public void onRequestPermissionsResult(int-requestCode,字符串[]权限,
//int[]格兰特结果)
//处理用户授予权限的情况。请参阅文档
//对于ActivityCompat,请请求权限以获取更多详细信息。
返回;
}
fusedLocation.getLastLocation().addOnCompleteListener(新的OnCompleteListener(){
@凌驾
未完成的公共void(@NonNull任务){
位置=task.getResult();
如果(位置!=null){
试一试{
地理编码器地理编码器=新地理编码器(
MainActivity.this,Locale.getDefault());
列表地址=geocoder.getFromLocation(location.getLatitude(),location.getLatitude(),1);
/*cityname.setText(Html.fromHtml(“城市名称:
”+地址.get(0.getAdminArea()));
setText(Html.fromHtml(“longtudent:
”+addresses.get(0.getLongitude()));
latitude.setText(Html.fromHtml(“latitude:
”+addresses.get(0.getLatitude()));
countryname.setText(Html.fromHtml(“国家名称:
”+地址.get(0.getCountryName()));
*/
APILINK=APILINK+addresses.get(0).getLatitude()+“&lon=“+addresses.get(0).getLength()+APIKEY;
}捕获(IOE异常){
e、 printStackTrace();
}
}
}
});
}
@非空
@凌驾
公共加载器onCreateLoader(int i,@Nullable Bundle){
Toast.makeText(MainActivity.this,String.valueOf(APILINK),Toast.LENGTH_SHORT.show();
返回新的WeatherLoader(此,APILINK);
}
@凌驾
public void onLoadFinished(@NonNull Loader,List modelList){
if(modelList!=null&&!modelList.isEmpty()){
mAdapter=新的WeatherAdapter(此,型号列表);
recyclerView.setAdapter(mAdapter);
}
}
@凌驾
public void onLoaderReset(@NonNull加载程序){
}
}
我不确定我是否完全理解这个问题/情况,但从提供的代码来看,似乎应该在onComplete方法中正确修改APILINK。如果您试图
public String getAPILINK() {
return APILINK;
}
System.out.println(APILINK);