一个简单的应用程序，在textview中显示纬度和经度;由于某种原因，它不显示相关数据。香港专业教育学院提供了java代码，xml，manifesta和logcat。 代码
package com.example.trucktracker;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.os.Build;
public class Locator extends ActionBarActivity {
TextView textLat;
TextView textLong;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_locator);
textLat = (TextView)findViewById(R.id.textLat);
textLong = (TextView)findViewById(R.id.textLong);
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener ll = new locatorlistener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, ll);
if (savedInstanceState == null)
{
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
}
class locatorlistener implements LocationListener
{
@Override
public void onLocationChanged(Location location) {
if(location != null)
{
double pLong = location.getLongitude();
double pLat = location.getLatitude();
textLat.setText(Double.toString(pLat));
textLong.setText(Double.toString(pLong));
}
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
Intent intent = getIntent();
setContentView(R.layout.activity_locator);
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.locator, 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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_locator,
container, false);
return rootView;
}
}
}
XML
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.trucktracker.Locator"
tools:ignore="MergeRootFrame" >
<TextView
android:id="@+id/latitudetext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/latitude"
tools:context=".Locator" />
<TextView
android:id="@+id/logitudetext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/latitudetext"
android:text="@string/longitude" />
<TextView
android:id="@+id/textLat"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/logitudetext"
android:text=""
android:layout_toRightOf="@+id/latitudetext" />
<TextView
android:id="@+id/textLong"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/logitudetext"
android:layout_alignBottom="@+id/logitudetext"
android:text=""
android:layout_toRightOf="@+id/logitudetext"/>
</RelativeLayout>
清单文件
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
logcat的
07-02 06:08:17.344: D/dalvikvm(535): GC_FOR_ALLOC freed 90K, 4% free 8346K/8648K, paused 62ms, total 69ms
07-02 06:08:17.464: I/Choreographer(535): Skipped 321 frames! The application may be doing too much work on its main thread.
07-02 06:08:17.714: D/dalvikvm(535): GC_FOR_ALLOC freed 44K, 4% free 9914K/10224K, paused 63ms, total 64ms
07-02 06:08:17.884: I/Choreographer(535): Skipped 84 frames! The application may be doing too much work on its main thread.
07-02 06:08:25.444: I/Choreographer(535): Skipped 41 frames! The application may be doing too much work on its main thread.
07-02 06:08:25.614: I/Choreographer(535): Skipped 36 frames! The application may be doing too much work on its main thread.
07-02 06:08:26.204: D/dalvikvm(535): GC_FOR_ALLOC freed 1404K, 15% free 9566K/11136K, paused 95ms, total 97ms
07-02 06:08:26.214: I/dalvikvm-heap(535): Grow heap (frag case) to 10.659MB for 1307824-byte allocation
07-02 06:08:26.284: D/dalvikvm(535): GC_FOR_ALLOC freed 2K, 13% free 10841K/12416K, paused 78ms, total 78ms
07-02 06:08:26.424: I/Choreographer(535): Skipped 81 frames! The application may be doing too much work on its main thread.
07-02 06:08:27.854: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.854: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.854: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.864: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.884: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.894: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.894: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.894: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:27.914: I/ActivityManager(381): START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.trucktracker/.MainActivity} from pid 535
07-02 06:08:27.964: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:28.014: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:28.014: E/SoundPool(381): error loading /system/media/audio/ui/KeypressStandard.ogg
07-02 06:08:28.014: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressStandard.ogg
07-02 06:08:28.014: E/SoundPool(381): error loading /system/media/audio/ui/KeypressSpacebar.ogg
07-02 06:08:28.024: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressSpacebar.ogg
07-02 06:08:28.024: E/SoundPool(381): error loading /system/media/audio/ui/KeypressDelete.ogg
07-02 06:08:28.024: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressDelete.ogg
07-02 06:08:28.024: E/SoundPool(381): error loading /system/media/audio/ui/KeypressReturn.ogg
07-02 06:08:28.024: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressReturn.ogg
07-02 06:08:28.024: E/SoundPool(381): error loading /system/media/audio/ui/KeypressInvalid.ogg
07-02 06:08:28.024: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressInvalid.ogg
07-02 06:08:28.024: W/AudioService(381): onLoadSoundEffects(), Error -1 while loading samples
07-02 06:08:28.124: D/gralloc(49): Registering a buffer in the process that created it. This may cause memory ordering problems.
07-02 06:08:28.124: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.124: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.124: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.134: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.134: E/SurfaceFlinger(49): glCheckFramebufferStatusOES error -190605487
07-02 06:08:28.134: E/SurfaceFlinger(49): got GL_FRAMEBUFFER_COMPLETE_OES error while taking screenshot
07-02 06:08:28.134: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.144: E/libEGL(49): called unimplemented OpenGL ES API
07-02 06:08:28.184: W/WindowManager(381): Screenshot failure taking screenshot for (246x410) to layer 21005
07-02 06:08:28.254: I/Choreographer(535): Skipped 97 frames! The application may be doing too much work on its main thread.
07-02 06:08:28.774: I/ActivityManager(381): Start proc com.example.trucktracker for activity com.example.trucktracker/.MainActivity: pid=1104 uid=10052 gids={50052}
07-02 06:08:28.854: D/dalvikvm(1104): Not late-enabling CheckJNI (already on)
07-02 06:08:30.864: I/Choreographer(535): Skipped 42 frames! The application may be doing too much work on its main thread.
07-02 06:08:31.134: I/Choreographer(381): Skipped 39 frames! The application may be doing too much work on its main thread.
07-02 06:08:31.204: I/ARMAssembler(49): generated scanline__00000077:03010104_00008001_00000000 [ 89 ipp] (110 ins) at [0xb6199680:0xb6199838] in 10000000 ns
07-02 06:08:31.294: I/Choreographer(381): Skipped 40 frames! The application may be doing too much work on its main thread.
07-02 06:08:32.064: D/dalvikvm(1104): GC_FOR_ALLOC freed 67K, 5% free 3135K/3276K, paused 50ms, total 54ms
07-02 06:08:32.064: I/dalvikvm-heap(1104): Grow heap (frag case) to 3.758MB for 659360-byte allocation
07-02 06:08:32.174: D/dalvikvm(1104): GC_FOR_ALLOC freed 6K, 4% free 3773K/3920K, paused 77ms, total 77ms
07-02 06:08:32.294: D/com.example.trucktracker.MainActivity(1104): Settings Text.
07-02 06:08:32.664: D/com.example.trucktracker.MainActivity(1104): Showing menu.
07-02 06:08:32.764: D/gralloc_goldfish(1104): Emulator without GPU emulation detected.
07-02 06:08:32.974: I/ActivityManager(381): Displayed com.example.trucktracker/.MainActivity: +4s304ms
07-02 06:08:36.234: D/com.example.trucktracker.MainActivity(1104): ClickedContinueButton
07-02 06:08:36.234: I/ActivityManager(381): START u0 {cmp=com.example.trucktracker/.Locator} from pid 1104
07-02 06:08:36.244: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.244: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.244: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/Effect_Tick.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/KeypressStandard.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressStandard.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/KeypressSpacebar.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressSpacebar.ogg
07-02 06:08:36.254: E/SoundPool(381): error loading /system/media/audio/ui/KeypressDelete.ogg
07-02 06:08:36.254: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressDelete.ogg
07-02 06:08:36.274: E/SoundPool(381): error loading /system/media/audio/ui/KeypressReturn.ogg
07-02 06:08:36.274: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressReturn.ogg
07-02 06:08:36.274: E/SoundPool(381): error loading /system/media/audio/ui/KeypressInvalid.ogg
07-02 06:08:36.284: W/AudioService(381): Soundpool could not load file: /system/media/audio/ui/KeypressInvalid.ogg
07-02 06:08:36.324: W/AudioService(381): onLoadSoundEffects(), Error -1 while loading samples
07-02 06:08:36.484: I/Choreographer(1104): Skipped 33 frames! The application may be doing too much work on its main thread.
07-02 06:08:38.174: I/Choreographer(381): Skipped 33 frames! The application may be doing too much work on its main thread.
07-02 06:08:38.204: I/ActivityManager(381): Displayed com.example.trucktracker/.Locator: +1s804ms
07-02 06:08:38.474: I/Choreographer(381): Skipped 40 frames! The application may be doing too much work on its main thread.
07-02 06:08:38.624: I/Choreographer(381): Skipped 36 frames! The application may be doing too much work on its main thread.
答案 0 :(得分：0)
首先要检查的是GPS启用了吗？
要检查的第二件事 - 您是否获得了位置锁定？您是否在通知栏上看到GPS符号？如果是这样闪烁或稳定？如果没有出现，GPS根本不会打开。如果它闪烁，你没有锁。在你有锁之前，它不会调用onLocationChanged。请注意，如果你在里面，你可能永远不会锁定。
您可以做的另一件事是将MOCK_LOCATIONS添加到您的权限并下载模拟位置应用。它会伪造GPS数据到您的应用程序进行测试。如果您这样做，请记住在发布之前删除该权限。
答案 1 :(得分：0)
请删除此
Intent intent = getIntent();
setContentView(R.layout.activity_locator);
来自
@Override
public boolean onCreateOptionsMenu(Menu menu)
每次打开菜单时，您基本上都在重新创建活动中的每个视图。这意味着您的textLat和textLong变量不再有效。您在其中设置的任何值都不会反映在应用
中