当用户触摸侧边菜单中的元素时，我正在尝试开始新活动。
这是MainActivity.java
public class MainActivity extends ActionBarActivity {
//First We Declare Titles And Icons For Our Navigation Drawer List View
//This Icons And Titles Are holded in an Array as you can see
String TITLES[] = { "Elenco Immagini", "Come partecipare", "Il concorso", "I premi" };
int ICONS[] = {R.drawable.ic_action_account_balance,R.drawable.ic_action_event,R.drawable.ic_action_message,R.drawable.ic_action_dashboard};
//Similarly we Create a String Resource for the name and email in the header view
//And we also create a int resource for profile picture in the header view
String NAME = "Christian Giupponi";
String EMAIL = "example@gmail.com";
int PROFILE = R.drawable.avatar_gplus;
private Toolbar toolbar;
RecyclerView mRecyclerView; // Declaring RecyclerView
RecyclerView.Adapter mAdapter; // Declaring Adapter For Recycler View
RecyclerView.LayoutManager mLayoutManager; // Declaring Layout Manager as a linear layout manager
DrawerLayout Drawer; // Declaring DrawerLayout
ActionBarDrawerToggle mDrawerToggle; // Declaring Action Bar Drawer Toggle
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/* Assinging the toolbar object ot the view
and setting the the Action bar to our toolbar
*/
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mRecyclerView = (RecyclerView) findViewById(R.id.RecyclerView); // Assigning the RecyclerView Object to the xml View
mRecyclerView.setHasFixedSize(true); // Letting the system know that the list objects are of fixed size
mAdapter = new MyAdapter(TITLES,ICONS,NAME,EMAIL,PROFILE,this); // Creating the Adapter of MyAdapter class(which we are going to see in a bit)
// And passing the titles,icons,header view name, header view email,
// and header view profile picture
mRecyclerView.setAdapter(mAdapter); // Setting the adapter to RecyclerView
final GestureDetector mGestureDetector = new GestureDetector(MainActivity.this, new GestureDetector.SimpleOnGestureListener() {
@Override public boolean onSingleTapUp(MotionEvent e) {
return true;
}
});
mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {
@Override
public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
View child = recyclerView.findChildViewUnder(motionEvent.getX(), motionEvent.getY());
if (child != null && mGestureDetector.onTouchEvent(motionEvent)) {
Drawer.closeDrawers();
int positionClicked = recyclerView.getChildPosition(child);
switch (positionClicked) {
case 1:
break;
case 2:
break;
case 3:
break;
case 4:
break;
default:
Toast.makeText(MainActivity.this, "The Item Clicked is: " + positionClicked, Toast.LENGTH_SHORT).show();
}
Toast.makeText(MainActivity.this, "The Item Clicked is: " + positionClicked, Toast.LENGTH_SHORT).show();
return true;
}
return false;
}
@Override
public void onTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
}
});
mLayoutManager = new LinearLayoutManager(this); // Creating a layout Manager
mRecyclerView.setLayoutManager(mLayoutManager); // Setting the layout Manager
Drawer = (DrawerLayout) findViewById(R.id.DrawerLayout); // Drawer object Assigned to the view
mDrawerToggle = new ActionBarDrawerToggle(this,Drawer,toolbar,R.string.openDrawer,R.string.closeDrawer){
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
// code here will execute once the drawer is opened( As I dont want anything happened whe drawer is
// open I am not going to put anything here)
}
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
// Code here will execute once drawer is closed
}
}; // Drawer Toggle Object Made
Drawer.setDrawerListener(mDrawerToggle); // Drawer Listener set to the Drawer toggle
mDrawerToggle.syncState(); // Finally we set the drawer toggle sync State
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
在onInterceptTouchEvent中我添加了一个开关来了解触摸了哪一行，我需要开始一个新的活动。
我试过用：
Intent i = new Intent(getApplicationContext(), OtherActivity.class);
startActivity(i);
但是当我运行应用程序时，它会停止，这就是logcat：
Process: com.christiangiupponi.provamaterialdesign, PID: 2579
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView$LayoutManager.onMeasure(android.support.v7.widget.RecyclerView$Recycler, android.support.v7.widget.RecyclerView$State, int, int)' on a null object reference
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1764)
at android.view.View.measure(View.java:17547)
at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:883)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2615)
at android.view.View.measure(View.java:17547)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2015)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1173)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1379)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
05-18 08:01:20.998 495-579/system_process E/InputDispatcher﹕ channel '364dd98e Toast (server)' ~ Channel is unrecoverably broken and will be disposed!
05-18 08:01:20.998 495-579/system_process E/InputDispatcher﹕ channel '3685bdbc com.christiangiupponi.provamaterialdesign/com.christiangiupponi.provamaterialdesign.HomeActivity (server)' ~ Channel is unrecoverably broken and will be disposed!