-3
mein CodeWarum stürzt meine App im Android Studio ab? Dies ist
public class MainActivity extends Activity {
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
private ViewPager viewPager;
private ViewPagerAdapter viewPagerAdapter;
private static android.widget.EditText favcolor;
private TextView textout;
private LinearLayout dotsLayout;
private TextView[] dots;
private int[] layouts;
private Button btnSkip, btnNext;
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.view_pager);
dotsLayout = (LinearLayout) findViewById(R.id.layoutDots);
btnNext = (Button) findViewById(R.id.btn_next);
layouts = new int[]{
R.layout.slide1,
R.layout.slide2,
R.layout.slide3};
// adding bottom dots
addBottomDots(0);
viewPagerAdapter = new ViewPagerAdapter();
viewPager.setAdapter(viewPagerAdapter);
viewPager.addOnPageChangeListener(viewPagerPageChangeListener);
}
public void btnNextClick(View v)
{
// checking for last page
// if last page home screen will be launched
int current = getItem(1);
if (current < layouts.length) {
// move to next screen
viewPager.setCurrentItem(current);
} else {
launchHomeScreen();
}
}
ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
addBottomDots(position);
// changing the next button text 'NEXT'/'GOT IT'
if (position == layouts.length - 1) {
// last page. make button text to GOT IT
favcolor = (android.widget.EditText) findViewById(R.id.text);
textout = (TextView) findViewById(R.id.txtOutput);
textout.setText(favcolor.getText());
btnNext.setText(getString(R.string.start));
btnSkip.setVisibility(View.GONE);
} else {
// still pages are left
btnNext.setText(getString(R.string.next));
btnSkip.setVisibility(View.VISIBLE);
}
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
@Override
public void onPageScrollStateChanged(int arg0) {
}
};
private void addBottomDots(int currentPage) {
dots = new TextView[layouts.length];
dotsLayout.removeAllViews();
for (int i = 0; i < dots.length; i++) {
dots[i] = new TextView(this);
dots[i].setText(Html.fromHtml("•"));
dots[i].setTextSize(35);
dots[i].setTextColor(getResources().getColor(R.color.dot_inactive));
dotsLayout.addView(dots[i]);
}
if (dots.length > 0)
dots[currentPage].setTextColor(getResources().getColor(R.color.dot_active));
}
private int getItem(int i) {
return viewPager.getCurrentItem() + i;
}
private void launchHomeScreen() {
startActivity(new Intent(this, MainActivity.class));
finish();
}
public class ViewPagerAdapter extends PagerAdapter {
private LayoutInflater layoutInflater;
public ViewPagerAdapter() {
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = layoutInflater.inflate(layouts[position], container, false);
container.addView(view);
return view;
}
@Override
public int getCount() {
return layouts.length;
}
@Override
public boolean isViewFromObject(View view, Object obj) {
return view == obj;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
View view = (View) object;
container.removeView(view);
}
/**
* A native method that is implemented by the 'native-lib' native library,
* which is packaged with this application.
*/
public native String stringFromJNI();
}
}
Und das ist der Fehler
01-28 12:30:06.827 26862-26862/com.example.jorgesalgado.singular20 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.jorgesalgado.singular20, PID: 26862
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.view.View$DeclaredOnClickListener.onClick(View.java:4725)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.view.View$DeclaredOnClickListener.onClick(View.java:4720)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setVisibility(int)' on a null object reference
at com.example.jorgesalgado.singular20.MainActivity$1.onPageSelected(MainActivity.java:103)
at android.support.v4.view.ViewPager.dispatchOnPageSelected(ViewPager.java:1967)
at android.support.v4.view.ViewPager.scrollToItem(ViewPager.java:685)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:669)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:630)
at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:611)
at com.example.jorgesalgado.singular20.MainActivity.btnNextClick(MainActivity.java:80)
at java.lang.reflect.Method.invoke(Native Method)
at android.view.View$DeclaredOnClickListener.onClick(View.java:4720)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at) com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776
ich mir ziemlich sicher bin, dass es mit etwas mit der Schaltfläche Weiter zu tun hat, aber ich bin nicht sicher. Bitte hilf mir. Ich bin 14 und verwende nur Javascript, CSS, Python und HTML. Ich nehme an, das ist Java und es ist ziemlich schwer zu lernen. Aber ich fange an, die Grundlagen zu verstehen.
'Verursacht durch: java.lang.NullPointerException: Der Versuch, virtuelle Methode‚Leere android.view.View.setVisibility aufzurufen (int) 'auf einem Null-Objekt' ... Zeile 103 Ihrer 'MainActivity' Sie versuchen eine Methode (' setVisibility') für eine Referenz aufzurufen, die nicht zugewiesen wurde (ihre Null). – trooper
Verwenden Sie dieses Innere onCreate - 'btnSkip = (Schaltfläche) findViewById (R.id.btn_skip);' – W4R10CK