我正在努力将Facebook Like按钮添加到应用程序一切正常，但运行应用程序时出现的问题并不知道究竟是什么问题
public class MainActivity extends AppCompatActivity {
Toolbar toolbar;
DrawerLayout mDrawerLayout;
NavigationView mNavigationView;
FragmentManager mFragmentManager;
FragmentTransaction mFragmentTransaction;
public static final String PROPERTY_REG_ID = "notifyId";
private static final String PROPERTY_APP_VERSION = "appVersion";
GoogleCloudMessaging gcm;
SharedPreferences preferences;
String reg_cgm_id;
static final String TAG = "MainActivity";
private AdView mAdView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Settings.sdkInitialize(this);
LikeView likeView = (LikeView) findViewById(R.id.like_view);
likeView.setObjectId("https://m.facebook.com/DZ.4.EverR");
likeView.setLikeViewStyle(LikeView.Style.STANDARD);
likeView.setAuxiliaryViewPosition(LikeView.AuxiliaryViewPosition.INLINE);
likeView.setHorizontalAlignment(LikeView.HorizontalAlignment.CENTER);
preferences = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
toolbar = (Toolbar) findViewById(R.id.toolbar);
if (toolbar != null) {
setSupportActionBar(toolbar);
}
//show admob banner ad
mAdView = (AdView) findViewById(R.id.adView);
mAdView.loadAd(new AdRequest.Builder().build());
mAdView.setAdListener(new AdListener() {
@Override
public void onAdClosed() {
}
@Override
public void onAdFailedToLoad(int error) {
mAdView.setVisibility(View.GONE);
}
@Override
public void onAdLeftApplication() {
}
@Override
public void onAdOpened() {
}
@Override
public void onAdLoaded() {
mAdView.setVisibility(View.VISIBLE);
}
});
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mNavigationView = (NavigationView) findViewById(R.id.main_drawer) ;
mFragmentManager = getSupportFragmentManager();
mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.replace(R.id.frame_container, new FragmentRecent()).commit();
mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
menuItem.setChecked(true);
mDrawerLayout.closeDrawers();
//setTitle(menuItem.getTitle());
if (menuItem.getItemId() == R.id.drawer_recent) {
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_container, new FragmentRecent()).commit();
}
if (menuItem.getItemId() == R.id.drawer_category) {
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_container, new FragmentCategory()).commit();
}
if (menuItem.getItemId() == R.id.drawer_favorite) {
FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.frame_container, new FragmentFavorite()).commit();
}
if (menuItem.getItemId() == R.id.drawer_rate) {
final String appName = getPackageName();
try {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + appName)));
} catch (android.content.ActivityNotFoundException anfe) {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://play.google.com/store/apps/details?id=" + appName)));
}
}
if (menuItem.getItemId() == R.id.drawer_more) {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(getString(R.string.play_more_apps))));
}
if (menuItem.getItemId() == R.id.drawer_setting) {
Intent i = new Intent(getBaseContext(), SettingsActivity.class);
startActivity(i);
}
return false;
}
});
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close);
mDrawerLayout.setDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
// init analytics tracker
((Analytics) getApplication()).getTracker();
// GCM
if (checkPlayServices()) {
gcm = GoogleCloudMessaging.getInstance(getApplicationContext());
String reg_cgm_id = getRegistrationId(getApplicationContext());
Log.i(TAG, "Play Services Ok.");
if (reg_cgm_id.isEmpty()) {
Log.i(TAG, "Find Register ID.");
registerInBackground();
}
} else {
Log.i(TAG, "No valid Google Play Services APK found.");
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case android.R.id.home:
onBackPressed();
return true;
default:
return super.onOptionsItemSelected(menuItem);
}
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
}
else {
super.onBackPressed();
}
}
@Override
public void onStart() {
super.onStart();
// analytics
GoogleAnalytics.getInstance(this).reportActivityStart(this);
}
@Override
public void onStop() {
super.onStop();
// analytics
GoogleAnalytics.getInstance(this).reportActivityStop(this);
}
@Override
protected void onPause() {
mAdView.pause();
super.onPause();
}
@Override
protected void onResume() {
super.onResume();
mAdView.resume();
}
@Override
protected void onDestroy() {
mAdView.destroy();
super.onDestroy();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
LikeView.handleOnActivityResult(this, requestCode, resultCode, data);
}
private boolean checkPlayServices() {
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(MainActivity.this);
if (resultCode != ConnectionResult.SUCCESS) {
if (GooglePlayServicesUtil.isUserRecoverableError(resultCode)) {
GooglePlayServicesUtil.getErrorDialog(resultCode, this, 9000).show();
} else {
Log.i(TAG, "This device is not supported.");
}
return false;
}
return true;
}
private void storeRegistrationId(Context context, String regId) {
int appVersion = getAppVersion(context);
Log.i(TAG, "Saving regId on app version " + appVersion);
SharedPreferences.Editor editor = preferences.edit();
editor.putString(PROPERTY_REG_ID, regId);
editor.putInt(PROPERTY_APP_VERSION, appVersion);
editor.commit();
}
private String getRegistrationId(Context context) {
String registrationId = preferences.getString(PROPERTY_REG_ID, "");
if (registrationId.isEmpty()) {
Log.i(TAG, "Registration not found.");
return "";
}
// Check if app was updated; if so, it must clear the registration ID
// since the existing regID is not guaranteed to work with the new
// app version.
int registeredVersion = preferences.getInt(PROPERTY_APP_VERSION, Integer.MIN_VALUE);
int currentVersion = getAppVersion(context);
if (registeredVersion != currentVersion) {
Log.i(TAG, "Analytics version changed.");
return "";
}
return registrationId;
}
private void registerInBackground() {
new AsyncTask<Void, Void, String>() {
@Override
protected String doInBackground(Void... params) {
String msg = "";
try {
if (gcm == null) {
gcm = GoogleCloudMessaging.getInstance(MainActivity.this);
}
reg_cgm_id = gcm.register(getString(R.string.google_api_sender_id));
msg = "Device registered, registration ID=" + reg_cgm_id;
Log.d(TAG, "ID GCM: " + reg_cgm_id);
sendRegistrationIdToBackend();
storeRegistrationId(MainActivity.this, reg_cgm_id);
} catch (IOException ex) {
msg = "Error :" + ex.getMessage();
}
return msg;
}
@Override
protected void onPostExecute(String msg) {
}
}.execute(null, null, null);
}
private static int getAppVersion(Context context) {
try {
PackageInfo packageInfo = context.getPackageManager()
.getPackageInfo(context.getPackageName(), 0);
return packageInfo.versionCode;
} catch (PackageManager.NameNotFoundException e) {
throw new RuntimeException("Could not get package name: " + e);
}
}
private void sendRegistrationIdToBackend() {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
nameValuePairs.add(new BasicNameValuePair("token", reg_cgm_id));
new HttpTask(null, MainActivity.this, Config.SERVER_URL + "/register.php", nameValuePairs, false).execute();
}
}
答案 0 :(得分：0)
这是您日志的重要部分：
java.lang.NullPointerException: Attempt to invoke virtual method
'void com.facebook.widget.LikeView.setObjectId(java.lang.String)'
on a null object reference at android.app.ActivityThread.performLaunchActivity
它说你试图在一个null的LikeView上调用方法setObjectId。因此，逐步完成代码的这一部分，找出为什么LikeView为空。