1
我嘗試在
android創建navigationDrawer和標籤，但得到這個異常：NullPointerException異常navigationDrawer和選項卡中的Android
06-20 17:10:35.717: E/AndroidRuntime(17235): FATAL EXCEPTION: main
06-20 17:10:35.717: E/AndroidRuntime(17235): Process: com.dusandimitrijevic.spisakzakupovinu, PID: 17235
06-20 17:10:35.717: E/AndroidRuntime(17235): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dusandimitrijevic.spisakzakupovinu/com.dusandimitrijevic.spisakzakupovinu.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2693)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2760)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread.access$900(ActivityThread.java:177)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.os.Handler.dispatchMessage(Handler.java:102)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.os.Looper.loop(Looper.java:145)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread.main(ActivityThread.java:5944)
06-20 17:10:35.717: E/AndroidRuntime(17235): at java.lang.reflect.Method.invoke(Native Method)
06-20 17:10:35.717: E/AndroidRuntime(17235): at java.lang.reflect.Method.invoke(Method.java:372)
06-20 17:10:35.717: E/AndroidRuntime(17235): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
06-20 17:10:35.717: E/AndroidRuntime(17235): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
06-20 17:10:35.717: E/AndroidRuntime(17235): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
06-20 17:10:35.717: E/AndroidRuntime(17235): at com.dusandimitrijevic.spisakzakupovinu.MainActivity.addDrawerItems(MainActivity.java:84)
06-20 17:10:35.717: E/AndroidRuntime(17235): at com.dusandimitrijevic.spisakzakupovinu.MainActivity.onCreate(MainActivity.java:55)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.Activity.performCreate(Activity.java:6289)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
06-20 17:10:35.717: E/AndroidRuntime(17235): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
06-20 17:10:35.717: E/AndroidRuntime(17235): ... 10 more
這裏的MainActivity的代碼：
package com.dusandimitrijevic.spisakzakupovinu;
import com.dusandimitrijevic.fragments.FragmentMojSpisak;
import com.dusandimitrijevic.fragments.FragmentProizvodi;
import com.dusandimitrijevic.fragments.FragmentSearch;
import com.tabs.dusandimitrijevic.SlidingTabLayout;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.style.ImageSpan;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
public class MainActivity extends ActionBarActivity {
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private String mActivityTitle;
private ListView mDrawerList;
private ArrayAdapter<String> mAdapter;
private Toolbar toolbar;
private ViewPager mPager;
private SlidingTabLayout mTabs;
private static final int MOJ_SPISAK = 0;
private static final int PROIZVODI = 1;
private static final int PROIZVODI_PRETRAGA = 2;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addDrawerItems();
setupDrawer();
mDrawerList = (ListView)findViewById(R.id.navList);
toolbar = (Toolbar) findViewById(R.id.app_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setIcon(R.drawable.ic_launcher);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
//podešavanja za navigationDrawer
mDrawerLayout = (DrawerLayout)findViewById(R.id.drawer_layout);
mActivityTitle = getTitle().toString();
//podešavanja za tabove
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
mTabs = (SlidingTabLayout) findViewById(R.id.tabs);
mTabs.setCustomTabView(R.layout.custom_tab_view, R.id.tabText);
mTabs.setDistributeEvenly(true);
mTabs.setBackgroundColor(getResources().getColor(R.color.primaryColor));
mTabs.setSelectedIndicatorColors(getResources().getColor(R.color.accentColor));
mTabs.setViewPager(mPager);
}
private void addDrawerItems() {
String[] osArray = { "Android", "iOS", "Windows", "OS X", "Linux" };
mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, osArray);
mDrawerList.setAdapter(mAdapter);
mDrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(MainActivity.this, "Time for an upgrade!", Toast.LENGTH_SHORT).show();
}
});
}
private void setupDrawer() {
mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
R.string.drawer_open, R.string.drawer_close) {
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
getSupportActionBar().setTitle("Navigation!");
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
getSupportActionBar().setTitle(mActivityTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerToggle.setDrawerIndicatorEnabled(true);
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
Toast.makeText(MainActivity.this, "Ovo su podešavanja", Toast.LENGTH_SHORT).show();
return true;
}
if (id == R.id.action_about) {
Toast.makeText(MainActivity.this, "O aplikaciji", Toast.LENGTH_SHORT).show();
return true;
}
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return super.onOptionsItemSelected(item);
}
class MyPagerAdapter extends FragmentStatePagerAdapter{
int icons[] = {R.drawable.ic_action,R.drawable.ic_action_1, R.drawable.ic_actio_2 };
String[] tabs;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
tabs=getResources().getStringArray(R.array.tabs);
}
@Override
public Fragment getItem(int num) {
Fragment fragment = null;
switch(num){
case MOJ_SPISAK:
fragment = FragmentMojSpisak.newInstance("", "");
break;
case PROIZVODI:
fragment = FragmentProizvodi.newInstance("", "");
break;
case PROIZVODI_PRETRAGA:
fragment = FragmentSearch.newInstance("", "");
break;
}
return fragment;
}
@Override
public CharSequence getPageTitle(int position) {
Drawable drawable = getDrawable(icons[position]);
drawable.setBounds(0, 0, 90, 90);
ImageSpan imageSpan = new ImageSpan(drawable);
SpannableString spannableString = new SpannableString(" ");
spannableString.setSpan(imageSpan, 0, spannableString.length(), Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
return spannableString;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return 3;
}
}
}
這是我的主要活動。 XML文件，我能做些什麼來使我的導航抽屜不超過動作欄，然後下面呢？
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.dusandimitrijevic.spisakzakupovinu.MainActivity" >
<include
android:id="@+id/app_bar"
layout="@layout/app_bar" />
<com.tabs.dusandimitrijevic.SlidingTabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="@color/primaryColor"/>
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1"
android:background="@android:color/white"
></android.support.v4.view.ViewPager>
</LinearLayout>
<ListView
android:id="@+id/navList"
android:layout_width="300dp"
android:layout_height="match_parent"
android:layout_gravity="left|start"
android:background="#ffeeeeee"/>
</android.support.v4.widget.DrawerLayout>
'at com.dusandimitrijevic.spisakzakupovinu.MainActivity.addDrawerItems（MainActivity.java:84）' - 這一行是什麼？ –
[嘗試調用虛方法'void android.widget.ListView.setAdapter]（http://stackoverflow.com/questions/29399066/attempt-to-invoke-virtual-method-void-android-widget-listview -setadapter） – Psypher