我想创建一个通过从左向右滑动打开的抽屉导航菜单，我是通过谷歌开发者教程完成的，但是该教程展示了如何创建抽屉导航以及如何设置菜单中的项目以打开新菜单 fragment 布局，但这不是我想要的..我想要的是使用抽屉导航菜单中的项目打开新 Activity ，我也这样做了，但是当 Sliding.java Activity 必须打开时，我的应用程序崩溃了.. Sliding.java 是包含菜单代码的 Activity 。
滑动.java:
package com.orar.cngcnasaud;
import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class Sliding extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mPlanetTitles;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
mPlanetTitles = getResources().getStringArray(R.array.planets_array);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// set a custom shadow that overlays the main content when the drawer opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
// set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
private void selectItem(int i) {
// TODO Auto-generated method stub
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
return false;
}
private class DrawerItemClickListener implements ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
}
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
mDrawerToggle.onConfigurationChanged(newConfig);
}
@SuppressWarnings("unused")
private void selectItem1(final int position) {
switch(position) {
case 1:
Intent a = new Intent(this, MainActivity.class);
startActivity(a);
break;
case 2:
Intent b = new Intent(this, Profesori.class);
startActivity(b);
break;
default:
}
}
}
我运行时没有错误，但它仍然崩溃..
编辑:
洛卡特:
02-17 16:29:58.496: I/dalvikvm(322): Could not find method com.orar.cngcnasaud.Sliding.getActionBar, referenced from method com.orar.cngcnasaud.Sliding.onCreate
02-17 16:29:58.496: W/dalvikvm(322): VFY: unable to resolve virtual method 5311: Lcom/orar/cngcnasaud/Sliding;.getActionBar ()Landroid/app/ActionBar;
02-17 16:29:58.496: D/dalvikvm(322): VFY: replacing opcode 0x6e at 0x0058
02-17 16:29:58.496: D/dalvikvm(322): VFY: dead code 0x005b-0087 in Lcom/orar/cngcnasaud/Sliding;.onCreate (Landroid/os/Bundle;)V
02-17 16:29:58.504: I/dalvikvm(322): Could not find method com.orar.cngcnasaud.Sliding.getActionBar, referenced from method com.orar.cngcnasaud.Sliding.setTitle
02-17 16:29:58.504: W/dalvikvm(322): VFY: unable to resolve virtual method 5311: Lcom/orar/cngcnasaud/Sliding;.getActionBar ()Landroid/app/ActionBar;
02-17 16:29:58.504: D/dalvikvm(322): VFY: replacing opcode 0x6e at 0x0002
02-17 16:29:58.504: D/dalvikvm(322): VFY: dead code 0x0005-000b in Lcom/orar/cngcnasaud/Sliding;.setTitle (Ljava/lang/CharSequence;)V
02-17 16:29:58.534: D/AndroidRuntime(322): Shutting down VM
02-17 16:29:58.534: W/dalvikvm(322): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
02-17 16:29:58.554: E/AndroidRuntime(322): FATAL EXCEPTION: main
02-17 16:29:58.554: E/AndroidRuntime(322): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.orar.cngcnasaud/com.orar.cngcnasaud.Sliding}: java.lang.NullPointerException
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.os.Handler.dispatchMessage(Handler.java:99)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.os.Looper.loop(Looper.java:123)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-17 16:29:58.554: E/AndroidRuntime(322): at java.lang.reflect.Method.invokeNative(Native Method)
02-17 16:29:58.554: E/AndroidRuntime(322): at java.lang.reflect.Method.invoke(Method.java:521)
02-17 16:29:58.554: E/AndroidRuntime(322): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-17 16:29:58.554: E/AndroidRuntime(322): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-17 16:29:58.554: E/AndroidRuntime(322): at dalvik.system.NativeStart.main(Native Method)
02-17 16:29:58.554: E/AndroidRuntime(322): Caused by: java.lang.NullPointerException
02-17 16:29:58.554: E/AndroidRuntime(322): at com.orar.cngcnasaud.Sliding.onCreate(Sliding.java:39)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-17 16:29:58.554: E/AndroidRuntime(322): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-17 16:29:58.554: E/AndroidRuntime(322): ... 11 more
02-17 16:30:06.275: I/Process(322): Sending signal. PID: 322 SIG: 9
滑动.xml:
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bff">
<!-- As the main content view, the view below consumes the entire
space available using match_parent in both dimensions. -->
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ListView
android:id="@+id/left_drawer"
android:layout_width="240dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"
android:background="#111"/>
</android.support.v4.widget.DrawerLayout>
最佳答案
这里有一个空指针:
Caused by: java.lang.NullPointerException at com.orar.cngcnasaud.Sliding.onCreate(Sliding.java:39)
这似乎是您的 DrawerLayout(无论如何都不确定该行):
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
你能检查/发布你的布局吗？
关于android - 如何使用抽屉导航打开新 Activity ？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21831771/