private void showDateDialog(List<Integer> date) {
DatePickerDialog.Builder builder = new DatePickerDialog.Builder(this);
builder.setOnDateSelectedListener(new DatePickerDialog.OnDateSelectedListener() {
@Override
public void onDateSelected(int[] dates) {
mTextView.setText(dates[0] + "-" + (dates[1] > 9 ? dates[1] : ("0" + dates[1])) + "-"
+ (dates[2] > 9 ? dates[2] : ("0" + dates[2])));
}
@Override
public void onCancel() {
}
})
.setMinYear(1900)
.setMaxYear(2050)
.setSelectYear(date.get(0) - 1)
.setSelectMonth(date.get(1) - 1)
.setSelectDay(date.get(2) - 1);
builder.setMaxYear(DateUtil.getYear());
builder.setMaxMonth(DateUtil.getDateForString(DateUtil.getToday()).get(1));
builder.setMaxDay(DateUtil.getDateForString(DateUtil.getToday()).get(2));
dateDialog = builder.create();
dateDialog.show();
}

private List<String> list = new ArrayList<>();

/**
* chooseDialog
*/
private void showChooseDialog(List<String> mlist) {
DataPickerDialog.Builder builder = new DataPickerDialog.Builder(this);
chooseDialog = builder.setData(mlist).setSelection(1).setTitle("取消")
.setOnDataSelectedListener(new DataPickerDialog.OnDataSelectedListener() {
@Override
public void onDataSelected(String itemValue, int position) {
mTextView.setText(itemValue);
}
@Override
public void onCancel() {
}
}).create();
chooseDialog.show();
}

public class TimePickerDialog extends Dialog

private static final class Params {
private boolean shadow = true;
private boolean canCancel = true;
private LoopView loopHour, loopMin;
private OnTimeSelectedListener callback;
}

protected void onDraw(Canvas canvas) 

核心就是它
canvas.drawText(as[j1], startX, h, paintB);

if (i2 <= n && h + i2 >= n) {
canvas.save();
canvas.clipRect(0, 0, v, n - i2);
canvas.drawText(as[j1], startX, h, paintA);
canvas.restore();
canvas.save();
canvas.clipRect(0, n - i2, v, (int) ((float) h * l));
canvas.drawText(as[j1], startX, h, paintB);
canvas.restore();
} else if (i2 <= o && h + i2 >= o) {
canvas.save();
canvas.clipRect(0, 0, v, o - i2);
canvas.drawText(as[j1], startX, h, paintB);
canvas.restore();
canvas.save();
canvas.clipRect(0, o - i2, v, (int) ((float) h * l));
canvas.drawText(as[j1], startX, h, paintA);
canvas.restore();
} else if (i2 >= n && h + i2 <= o) {
canvas.clipRect(0, 0, v, (int) ((float) h * l));
canvas.drawText(as[j1], startX, h, paintB);
mSelectItem = arrayList.indexOf(as[j1]);
} else {
canvas.clipRect(0, 0, v, (int) ((float) h * l));
canvas.drawText(as[j1], startX, h, paintA);
}
canvas.restore();

public boolean onTouchEvent(MotionEvent motionevent)

case MotionEvent.ACTION_MOVE:
y = motionevent.getRawY();
z = x - y;
x = y;
totalScrollY = (int) ((float) totalScrollY + z);
if (!isLoop) {
if (totalScrollY > (int) ((float) (-positon) * (l * (float) h))) {
break; /* Loop/switch isn't completed */
}
totalScrollY = (int) ((float) (-positon) * (l * (float) h));
}
break;