LocationManager无法正常工作，没有任何错误

Question

如果我点击＆＃34;找到我的位置＆＃34;按钮，然后我的位置信息应该显示在TextView上，但不起作用。 这是一个简单的代码，但我不知道这出错了。似乎代码中没有错误......可能是我手机的问题？

MainActivity.java

package org.androidtown.mylocation;

import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity {
    TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = (TextView) findViewById(R.id.textView);
    }

    public void onButton1Clicked(View v){
        LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        long minTime = 10000;
        float minDistance = 0;

        MyLocationListener listener = new MyLocationListener();

        manager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
                minTime, minDistance, listener);

        manager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
                minTime, minDistance, listener);

        Location lastLocation = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if (lastLocation != null){
            Double latitude = lastLocation.getLatitude(); 
            Double longitude = lastLocation.getLongitude(); 

            textView.setText("My Latest Location: " + latitude + ", " + longitude);
            textView.invalidate();
        }

    }

    class MyLocationListener implements LocationListener {
        @Override
        public void onLocationChanged(Location location) {
            Double latitude = location.getLatitude(); 
            Double longitude = location.getLongitude(); 

            textView.setText("My Location: " + latitude + ", " + longitude);
            textView.invalidate();
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.androidtown.mylocation" >

    <!-- GPS -->
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <!-- NETWORK -->
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Find My Location"
        android:id="@+id/button"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:onClick="onButton1Clicked" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="My Location"
        android:id="@+id/textView"
        android:layout_below="@+id/button"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="83dp" />
</RelativeLayout>