Android开发【03-29视频贴】为什么书上可以在子线程更新UI

package com.example.lbstest;
import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.Toast;
import com.baidu.location.BDLocation;
import com.baidu.location.BDLocationListener;
import com.baidu.location.LocationClient;
import com.baidu.location.LocationClientOption;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
public LocationClient mLocationClient;
private TextView positionText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mLocationClient = new LocationClient(getApplicationContext());
mLocationClient.registerLocationListener(new MyLocationListener());
setContentView(R.layout.activity_main);
positionText = (TextView) findViewById(R.id.position_text_view);
List<String> permissionList = new ArrayList<>();
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
permissionList.add(Manifest.permission.ACCESS_FINE_LOCATION);
}
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {
permissionList.add(Manifest.permission.READ_PHONE_STATE);
}
if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
permissionList.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
}
if (!permissionList.isEmpty()) {
String[] permissions = permissionList.toArray(new String[permissionList.size()]);
ActivityCompat.requestPermissions(MainActivity.this, permissions, 1);
} else {
requestLocation();
}
}
private void requestLocation() {
initLocation();
mLocationClient.start();
}
private void initLocation() {
LocationClientOption option = new LocationClientOption();
option.setScanSpan(5000);
option.setIsNeedAddress(true);
mLocationClient.setLocOption(option);
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
switch (requestCode) {
case 1:
if (grantResults.length > 0) {
for (int result : grantResults) {
if (result != PackageManager.PERMISSION_GRANTED) {
Toast.makeText(this, "必须同意所有权限才能使用本程序", Toast.LENGTH_SHORT).show();
finish();
return;
}
}
requestLocation();
} else {
Toast.makeText(this, "发生未知错误", Toast.LENGTH_SHORT).show();
finish();
}
break;
default:
}
}
public class MyLocationListener implements BDLocationListener {
@Override
public void onReceiveLocation(BDLocation location) {
StringBuilder currentPosition = new StringBuilder();
currentPosition.append("纬度：").append(location.getLatitude()).append("\n");
currentPosition.append("经线：").append(location.getLongitude()).append("\n");
currentPosition.append("国家：").append(location.getCountry()).append("\n");
currentPosition.append("省：").append(location.getProvince()).append("\n");
currentPosition.append("市：").append(location.getCity()).append("\n");
currentPosition.append("区：").append(location.getDistrict()).append("\n");
currentPosition.append("街道：").append(location.getStreet()).append("\n");
currentPosition.append("定位方式：");
if (location.getLocType() == BDLocation.TypeGpsLocation) {
currentPosition.append("GPS");
} else if (location.getLocType() == BDLocation.TypeNetWorkLocation) {
currentPosition.append("网络");
}
positionText.setText("currentPosition");
}
}
@Override
protected void onDestroy() {
super.onDestroy();
mLocationClient.stop();
}
}
这是第一行代码第11章百度地图部分， 为什么书上的代码可以在子线程中更新UI，导入studio运行没问题。
我自己对着写的就会报错， 代码是和书上一样的。 除了百度jar包是我自己下载的， 难道是jar包问题？？？