Custom View embed in Gallery crashes while key press
- by tao
Hi there,
I'd like to find some stuff to replace the Tab component, so I'd make a custom View named StringView, which has the ability to display text, and to embed it into a Gallery. But it always crashes with error "NullPointerException at InputMethodManager".
I have no idea about this, any help&tip&suggest are appreciate.
Detail of my issue:
First
I'd created a class StringView extends View:
public class StringView extends View {
protected final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
protected String mString;
protected int mAscent;
// Constructor
public StringView(Context context, String string) {
super(context);
mPaint.setARGB(255, 255, 60, 10);
mPaint.setTextSize(30);
//mPaint.setFakeBoldText(true);
mString = string;
setPadding(20,15,20,15);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int w = this.getPaddingLeft();
int h = this.getPaddingTop() - mAscent;
canvas.drawText(mString, w, h, mPaint);
}
public void setString(String str) {
mString = str;
this.requestLayout();
this.invalidate();
}
public String getString() {
return mString;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(measureWidth(widthMeasureSpec),
measureHeight(heightMeasureSpec));
}
/**
* Determines the width of this view
* @param measureSpec A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text
result = (int) mPaint.measureText(mString) + getPaddingLeft()
+ getPaddingRight();
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
/**
* Determines the height of this view
* @param measureSpec A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
mAscent = (int) mPaint.ascent();
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else {
// Measure the text (beware: ascent is a negative number)
result = (int) (-mAscent + mPaint.descent()) + getPaddingTop()
+ getPaddingBottom();
if (specMode == MeasureSpec.AT_MOST) {
// Respect AT_MOST value if that was what is called for by measureSpec
result = Math.min(result, specSize);
}
}
return result;
}
}
Second
I put it in to Gallery through Adapter
Gallery gallery = (Gallery) findViewById(R.id.gallery);
gallery.setAdapter(new ImageAdapter(this));
ImageAdapter:
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private View[] mImages = genSerielImageViews();
public ImageAdapter(Context c) {
mContext = c;
TypedArray a = obtainStyledAttributes(R.styleable.Gallery);
mGalleryItemBackground = a.getResourceId(
R.styleable.Gallery_android_galleryItemBackground, 0);
a.recycle();
}
private View[] genSerielImageViews() {
if (true) {
int N = 6;
StringView[] views = new StringView[N];
for (int i=0; i<N; i++) {
views[i] = new StringView(mContext, "ITEM #" +
Integer.toString(i) );
}
return views;
}
else {
int N = 6;
TextView[] views = new TextView[N];
for (int i=0; i<N; i++) {
views[i] = new TextView( mContext );
views[i].setText("CCTV #" + Integer.toString(i) );
}
return views;
}
}
public int getCount() {
return mImages.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
return mImages[position];
}
}
Then Compile&Run, press keypad RIGHT and I got a crash, It's turns out a weird InputMethodManager error:
03-18 07:22:33.568:
ERROR/AndroidRuntime(958): Uncaught
handler: thread main exiting due to
uncaught exception 03-18 07:22:33.648:
ERROR/AndroidRuntime(958):
java.lang.NullPointerException 03-18
07:22:33.648:
ERROR/AndroidRuntime(958): at
android.view.inputmethod.InputMethodManager.startInputInner(InputMethodManager.java:940)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
android.view.inputmethod.InputMethodManager.checkFocus(InputMethodManager.java:1114)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
android.view.ViewRoot.handleMessage(ViewRoot.java:1869)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
android.os.Handler.dispatchMessage(Handler.java:99)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
android.os.Looper.loop(Looper.java:123)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
android.app.ActivityThread.main(ActivityThread.java:4310)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
java.lang.reflect.Method.invokeNative(Native
Method) 03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
java.lang.reflect.Method.invoke(Method.java:521)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
03-18 07:22:33.648:
ERROR/AndroidRuntime(958): at
dalvik.system.NativeStart.main(Native
Method)
Thanks.
