java.lang.NullPointerException: intento de Android de invocar el error del método virtual
Mi aplicación de fragmentos de vista web de Android se bloquea, después de agregar un botón para pasar de un fragmento a otro, el error en la consola es:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.ahmed.stories, PID: 11846
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.ahmed.stories.MainActivity.setUrl(java.lang.String)' on a null object reference at com.ahmed.stories.Saying$3.onPageStarted(Saying.java:127)
at com.android.webview.chromium.WebViewContentsClientAdapter.onPageStarted(WebViewContentsClientAdapter.java:517)
at org.chromium.android_webview.AwContentsClientCallbackHelper$MyHandler.handleMessage(AwContentsClientCallbackHelper.java:144)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:5728)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)
Dice que el problema es con la línea 127 que está con((MainActivity) getActivity()).setUrl(url); pero no puedo encontrar nada malo en ello, estoy en Android y estoy tratando de aprender, quizás ustedes puedan ayudar.
Actividad principa
package com.ahmed.stories;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.customtabs.CustomTabsIntent;
import android.support.design.widget.BottomNavigationView;
import android.support.design.widget.NavigationView;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.CardView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, View.OnClickListener {
FragmentManager fragmentManager;
FragmentTransaction fragmentTransaction;
TextView home_tv, stories, bookmarks, drafts, fakecheck, lost, leaving;
CardView lyt_top_bar;
View toolbar_line;
BottomNavigationView navigation;
BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Home home = new Home();
fragmentTransaction.replace(R.id.fragmentContainer, home, "Home");
fragmentTransaction.commit();
return true;
case R.id.navigation_search:
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Search search = new Search();
fragmentTransaction.replace(R.id.fragmentContainer, search, "Home");
fragmentTransaction.commit();
return true;
case R.id.navigation_edit:
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Edit edit = new Edit();
fragmentTransaction.replace(R.id.fragmentContainer, edit, "Home");
fragmentTransaction.commit();
return true;
case R.id.navigation_message:
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Notification notification = new Notification();
fragmentTransaction.replace(R.id.fragmentContainer, notification, "Home");
fragmentTransaction.commit();
return true;
case R.id.navigation_profile:
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Profile profile = new Profile();
fragmentTransaction.replace(R.id.fragmentContainer, profile, "Home");
fragmentTransaction.commit();
return true;
}
return false;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main3);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
navigation = (BottomNavigationView) findViewById(R.id.navigation);
BottomNavigationViewHelper.disableShiftMode(navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.navigation));
bookmarks = findViewById(R.id.bookmarks);
stories = findViewById(R.id.stories);
home_tv = findViewById(R.id.home_tv);
lyt_top_bar = findViewById(R.id.lyt_top_bar);
toolbar_line = findViewById(R.id.toolbar_line);
stories.setOnClickListener(this);
home_tv.setOnClickListener(this);
bookmarks.setOnClickListener(this);
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Home home = new Home();
fragmentTransaction.replace(R.id.fragmentContainer, home, "Home");
fragmentTransaction.commit();
}
@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 boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main3, 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) {
shareTextUrl();
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
showSystemUI();
if (id == R.id.nav_camera) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Profile profile = new Profile();
fragmentTransaction.replace(R.id.fragmentContainer, profile, "Home");
fragmentTransaction.commit();
// Handle the camera action
} else if (id == R.id.nav_gallery) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Edit edit = new Edit();
fragmentTransaction.replace(R.id.fragmentContainer, edit, "Home");
fragmentTransaction.commit();
} else if (id == R.id.nav_slideshow) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Drafts drafts = new Drafts();
fragmentTransaction.replace(R.id.fragmentContainer, drafts, "Home");
fragmentTransaction.commit();
} else if (id == R.id.nav_manage) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Fakecheck fakecheck = new Fakecheck();
fragmentTransaction.replace(R.id.fragmentContainer, fakecheck, "Home");
fragmentTransaction.commit();
} else if (id == R.id.nav_lost) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Lost lost = new Lost();
fragmentTransaction.replace(R.id.fragmentContainer, lost, "Home");
fragmentTransaction.commit();
} else if (id == R.id.nav_send) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Leaving leaving = new Leaving();
fragmentTransaction.replace(R.id.fragmentContainer, leaving, "Home");
fragmentTransaction.commit();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
private void hideSystemUI() {
lyt_top_bar.setVisibility(View.GONE);
navigation.setVisibility(View.GONE);
toolbar_line.setVisibility(View.GONE);
}
public void showSystemUI() {
lyt_top_bar.setVisibility(View.VISIBLE);
navigation.setVisibility(View.VISIBLE);
toolbar_line.setVisibility(View.VISIBLE);
// View decorView = getWindow().getDecorView();
// decorView.setSystemUiVisibility(
// View.SYSTEM_UI_FLAG_LAYOUT_STABLE
// );
}
@Override
public void onClick(View v) {
showSystemUI();
if (v == home_tv) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Saying saying = new Saying();
fragmentTransaction.replace(R.id.fragmentContainer, saying, "Home");
fragmentTransaction.commit();
saying.hideProgress();
hideSystemUI();
}
if (v == bookmarks) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Bookmarks bookmarks = new Bookmarks();
fragmentTransaction.replace(R.id.fragmentContainer, bookmarks, "Home");
fragmentTransaction.commit();
}
if (v == drafts) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Drafts drafts = new Drafts();
fragmentTransaction.replace(R.id.fragmentContainer, drafts, "Home");
fragmentTransaction.commit();
}
if (v == fakecheck) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Fakecheck fakecheck = new Fakecheck();
fragmentTransaction.replace(R.id.fragmentContainer, fakecheck, "Home");
fragmentTransaction.commit();
}
if (v == lost) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Lost lost = new Lost();
fragmentTransaction.replace(R.id.fragmentContainer, lost, "Home");
fragmentTransaction.commit();
}
if (v == leaving) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Leaving leaving = new Leaving();
fragmentTransaction.replace(R.id.fragmentContainer, leaving, "Home");
fragmentTransaction.commit();
}
if (v == stories) {
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Trending trending = new Trending();
fragmentTransaction.replace(R.id.fragmentContainer, trending, "Home");
fragmentTransaction.commit();
}
}
String urlOpen="";
public void setUrl(String url){
this.urlOpen = url;
}
public void shareTextUrl(){
Intent share = new Intent(android.content.Intent.ACTION_SEND);
share.setType("text/plain");
share.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
// Add data to the intent, the receiving app will decide
// what to do with it.
share.putExtra(Intent.EXTRA_SUBJECT, "Title Of The Post");
share.putExtra(Intent.EXTRA_TEXT, urlOpen);
startActivity(Intent.createChooser(share, "We Only share with the people we care!"));
}
public void goToHome(){
showSystemUI();
fragmentManager = getFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
Home home = new Home();
fragmentTransaction.replace(R.id.fragmentContainer, home, "Home");
fragmentTransaction.commit();
}
}
Fragmento Diciendo
package com.ahmed.stories;
import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceError;
import android.webkit.WebResourceRequest;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ImageButton;
import android.widget.ProgressBar;
import java.io.File;
/**
* Created by ahmed on 21/4/18.
*/
public class Saying extends BaseFragment {
private String postUrl = "https://wewritesay.herokuapp.com";
private ProgressBar progressBar;
WebView home_web;
ImageButton btn_home;
private float m_downX;
//
public Saying() {
// Required empty public constructor
}
@Override
public void hideProgress() {
if (progressBar != null)
progressBar.setVisibility(View.GONE);
}
// https://my-medium-clone.herokuapp.com/top-stories
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onResume() {
super.onResume();
((AppCompatActivity) getActivity()).getSupportActionBar().hide();
}
@Override
public void onStop() {
super.onStop();
((AppCompatActivity) getActivity()).getSupportActionBar().show();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_saying, container, false);
home_web = (WebView) view.findViewById(R.id.home_web);
btn_home = view.findViewById(R.id.btn_home);
btn_home.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
((MainActivity) getActivity()).goToHome();
}
});
WebSettings settings = home_web.getSettings();
settings.setJavaScriptEnabled(true);
home_web.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
home_web.getSettings().setAppCacheEnabled(true);
settings.setDomStorageEnabled(true);
settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
settings.setUseWideViewPort(true);
settings.setSavePassword(true);
settings.setSaveFormData(true);
settings.setEnableSmoothTransition(true);
progressBar = (ProgressBar) view.findViewById(R.id.progressBar);
// home_web.getSettings().setJavaScriptEnabled(true);
home_web.loadUrl(postUrl);
home_web.setOnKeyListener(new View.OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && home_web.canGoBack()) {
home_web.goBack();
return true;
}
return false;
}
});
initWebView();
// home_web.setHorizontalScrollBarEnabled(false);
return view;
}
private class MyWebChromeClient extends WebChromeClient {
Context context;
public MyWebChromeClient(Context context) {
super();
this.context = context;
}
}
private void initWebView() {
home_web.setWebChromeClient(new Saying.MyWebChromeClient(getActivity()));
home_web.setWebViewClient(new WebViewClient() {
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
super.onPageStarted(view, url, favicon);
((MainActivity) getActivity()).setUrl(url);
progressBar.setVisibility(View.VISIBLE);
// invalidateOptionsMenu();
}
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
home_web.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
progressBar.setVisibility(View.GONE);
// invalidateOptionsMenu();
}
@Override
public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
super.onReceivedError(view, request, error);
progressBar.setVisibility(View.GONE);
// invalidateOptionsMenu();
}
});
home_web.clearCache(true);
home_web.clearHistory();
home_web.getSettings().setJavaScriptEnabled(true);
home_web.setHorizontalScrollBarEnabled(false);
home_web.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (event.getPointerCount() > 1) {
//Multi touch detected
return true;
}
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
// save the x
m_downX = event.getX();
}
break;
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP: {
// set x so that it doesn't move
event.setLocation(m_downX, event.getY());
}
break;
}
return false;
}
});
}
}