I have I problem with my custom GridView. I wrote the custom GridViewClass to enable the fling gesture within the GridView. However, there are some errors I don’t quite understand.
My code:
<pl.flamis.GestureGridView
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:numColumns="7"
android:id="@+id/calendar"
android:listSelector="#00000000"
android:layoutAnimation="@anim/wave_scale"
android:background="#c5c5c7" >
</pl.flamis.GestureGridView>
the custom GridView class:
public class GestureGridView extends GridView {
private GestureDetector gd;
public GestureGridView(final Context context, AttributeSet attrs) {
super(context);
gd = new GestureDetector(context,
new GestureDetector.OnGestureListener() {
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
return false;
}
@Override
public boolean onDown(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
});
}
@Override
public boolean onTouchEvent(MotionEvent event) {
gd.onTouchEvent(event);
return true;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
return gd.onTouchEvent(ev);
}
}
the main class code:
public class Kalendarz extends Activity implements OnGestureListener{
//Grid data
public static GestureGridView calendar;
private static CellAdapter cell_adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myGesture = new GestureDetector(this);
context = getApplicationContext();
res = getResources();
Notes = new Notes();
tble = new Timetable(Notes);
MDate = new MonthData(tble.getDay(), tble.schift_sys );
setContentView(R.layout.kalendarz);
if(tble.schift_sys == -1)
showDialog(sys_zmian);
Button next = (Button) findViewById(R.id.next_month);
next.setOnClickListener(
new OnClickListener(){
@Override
public void onClick(View v) {
tble.goNextMonth();
updateDateInfo();
for(int i=0; i< calendar.getChildCount(); i++){
CellButton b = ((CellButton)((LinearLayout)calendar.getChildAt(i)).getChildAt(0));
if(i >= tble.getFday()-1 && i < tble.getFday() -1 + tble.getNodays()){
b.setText(String.valueOf(i-tble.getFday()+2));
}else{
b.setText("-1");
}
}
findViewById(R.id.calendar).invalidate();
((GestureGridView)findViewById(R.id.calendar)).startLayoutAnimation();
}
}
);
Button prev = (Button) findViewById(R.id.previous_month);
prev.setOnClickListener(
new OnClickListener(){
@Override
public void onClick(View v) {
tble.goPrevMonth();
updateDateInfo();
for(int i=0; i< calendar.getChildCount(); i++){
CellButton b = ((CellButton)((LinearLayout)calendar.getChildAt(i)).getChildAt(0));
if(i >= tble.getFday()-1 && i < tble.getFday() -1 + tble.getNodays()){
b.setText(String.valueOf(i-tble.getFday()+2));
}else{
b.setText("-1");
}
}
findViewById(R.id.calendar).invalidate();
((GestureGridView)findViewById(R.id.calendar)).startLayoutAnimation();
}
}
);
GridView day_names = (GridView)findViewById(R.id.day_names);
day_names.setAdapter( new ArrayAdapter <CharSequence> (
this,
R.layout.day_names_element,
res.getStringArray(R.array.days)
)
);
calendar = (GestureGridView)findViewById(R.id.calendar);
cell_adapter = new CellAdapter(this);
calendar.setAdapter(cell_adapter);
updateDateInfo();
/*Intent j = new Intent(this, Service.class);
startService(j);*/
}
public class CellAdapter extends BaseAdapter{
Context MyContext;
public CellAdapter(Context _MyContext) {
MyContext = _MyContext;
}
@Override
public int getCount() {
return 6*7;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View MyView = convertView;
if ( convertView == null ){
//Inflate the layout
LayoutInflater li = getLayoutInflater();
MyView = li.inflate(R.layout.cell_calendar_element, null);
Button b = (Button)MyView.findViewById(R.id.cellbutton);
registerForContextMenu(b);
}
Button b = (Button)MyView.findViewById(R.id.cellbutton);
if(position >= tble.getFday()-2 && position < tble.getFday()-1 + tble.getNodays()){
b.setText(String.valueOf(position-tble.getFday()+2));
}else{
b.setText("0");
}
return MyView;
}
}
public void updateDateInfo(){
TextView date_info = (TextView)findViewById(R.id.date_info);
CharSequence months[] = res.getTextArray(R.array.miesiace);
date_info.setText(months[tble.getDay().getMM()-1].toString()+" "+tble.getDay().getYYYY());
}
@Override
public boolean onDown(MotionEvent arg0) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
// TODO Auto-generated method stub
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
return false;
if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Button b1 = (Button)findViewById(R.id.next_month);
b1.performClick();
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
Button b2 = (Button)findViewById(R.id.previous_month);
b2.performClick();
}
return true;
} catch (Exception e) {
// nothing
Toast.makeText(getApplicationContext(), "left", Toast.LENGTH_LONG).show();
}
return false;
}
@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}
@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
@Override
public boolean onTouchEvent(MotionEvent event){
return myGesture.onTouchEvent(event);
}
}
and the error code:
03-02 16:30:27.301: E/AndroidRuntime(2132): FATAL EXCEPTION: main
03-02 16:30:27.301: E/AndroidRuntime(2132): java.lang.RuntimeException: Unable to start activity ComponentInfo{pl.flamis/pl.flamis.Kalendarz}: java.lang.NullPointerException
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.os.Handler.dispatchMessage(Handler.java:99)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.os.Looper.loop(Looper.java:123)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread.main(ActivityThread.java:3647)
03-02 16:30:27.301: E/AndroidRuntime(2132): at java.lang.reflect.Method.invokeNative(Native Method)
03-02 16:30:27.301: E/AndroidRuntime(2132): at java.lang.reflect.Method.invoke(Method.java:507)
03-02 16:30:27.301: E/AndroidRuntime(2132): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-02 16:30:27.301: E/AndroidRuntime(2132): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-02 16:30:27.301: E/AndroidRuntime(2132): at dalvik.system.NativeStart.main(Native Method)
03-02 16:30:27.301: E/AndroidRuntime(2132): Caused by: java.lang.NullPointerException
03-02 16:30:27.301: E/AndroidRuntime(2132): at pl.flamis.Kalendarz.onCreate(Kalendarz.java:304)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-02 16:30:27.301: E/AndroidRuntime(2132): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1586)
03-02 16:30:27.301: E/AndroidRuntime(2132): ... 11 more
I’ve spent over a day trying different solutions and nothing seems to work. I will appreciate any help. Thanks in advance!
EDIT: I attached the source code of the main class – if I change all the GestureGridView to GridView – it works like a charm, BUT fling does not work on the GridView – however it works on the rest of the layout. I need to make it work on the GridView too.
I actually found another solution, because the way I tried to do it simply didn’t work and nobody knows why. I used GestureOverlayView instead, and it works great. Just had to add two swipe gestures to the gesture library.