android - 等待函数运行然后开始活动

Question

当用户按下开始按钮时，会运行检查以查看 GPS 是否已启用，然后启动活动。checkGPS 使用警报管理器。

case R.id.startbtn:
        checkGPS();
        Intent gpslocation=new Intent(this,selection.class);
        startActivity(gpslocation);
        break;

如何完成等待用户启用 GPS 然后开始活动？

Answer 1

1）在onCreate()方法中，LocationListener在您的 Activity 上注册：

   // get location manager
   LocationManager lManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
   Button btnStart = (Button)findViewById(R.id.btnStart);
   btnStart.setOnClickListener(new OnClickListener() {
       @Override
       public void onClick(View v) {
            lManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, YourActivity.this);
       }
   });

2）您的活动应实施LocationListener：

   public class YourActivity extends Activity implements LocationListener {

3）覆盖方法LocationListener：

@Override public void onLocationChanged(Location location) { // 当位置改变时 Log.d(TAG, "location changed.");
}

@Override
public void onProviderDisabled(String provider) {
     // when the source (GSP or GSM network) are disabled
     Log.d(TAG, "the source "+provider+" has been disabled");
}

@Override
public void onProviderEnabled(String provider) {
     Log.i(TAG, "the source "+provider+" has been enabled");
     //here you should test if the provider enabled is GPS , if yes , then launch your GPSActivity
     if(provider.equals("gps") {
           Intent gpslocation=new Intent(this,selection.class);
           startActivity(gpslocation);
     }
     else {
           //launch your alert dialog here
     }
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
     Log.i(TAG, "source status "+provider+" has been changed to : "+status);
}