初学者，尝试修改Pebble提供的一个示例应用程序，但是我正在失去理智。
在下面的代码中，我无法在屏幕上实际呈现TextLayer * s_weather_label。不知道为什么......没有错误出现，应用程序编译得很好。
#include "simple_analog.h"
#include "pebble.h"
static Window *window;
static Layer *s_simple_bg_layer, *s_date_layer, *s_hands_layer;
static BitmapLayer *s_background_layer;
static GBitmap *s_background_bitmap;
static TextLayer *s_day_label, *s_num_label, *s_weather_label;
static GPath *s_tick_paths[NUM_CLOCK_TICKS];
static GPath *s_minute_arrow, *s_hour_arrow;
static char s_num_buffer[4], s_day_buffer[6];
static void bg_update_proc(Layer *layer, GContext *ctx) {
graphics_context_set_fill_color(ctx, GColorBlack);
graphics_fill_rect(ctx, layer_get_bounds(layer), 0, GCornerNone);
graphics_context_set_fill_color(ctx, GColorWhite);
for (int i = 0; i < NUM_CLOCK_TICKS; ++i) {
gpath_draw_filled(ctx, s_tick_paths[i]);
}
}
static void hands_update_proc(Layer *layer, GContext *ctx) {
GRect bounds = layer_get_bounds(layer);
GPoint center = grect_center_point(&bounds);
int16_t second_hand_length = bounds.size.w / 2;
time_t now = time(NULL);
struct tm *t = localtime(&now);
int32_t second_angle = TRIG_MAX_ANGLE * t->tm_sec / 60;
GPoint second_hand = {
.x = (int16_t)(sin_lookup(second_angle) * (int32_t)second_hand_length / TRIG_MAX_RATIO) + center.x,
.y = (int16_t)(-cos_lookup(second_angle) * (int32_t)second_hand_length / TRIG_MAX_RATIO) + center.y,
};
// second hand
graphics_context_set_stroke_color(ctx, GColorWhite);
graphics_draw_line(ctx, second_hand, center);
// minute/hour hand
graphics_context_set_fill_color(ctx, GColorWhite);
graphics_context_set_stroke_color(ctx, GColorBlack);
gpath_rotate_to(s_minute_arrow, TRIG_MAX_ANGLE * t->tm_min / 60);
gpath_draw_filled(ctx, s_minute_arrow);
gpath_draw_outline(ctx, s_minute_arrow);
gpath_rotate_to(s_hour_arrow, (TRIG_MAX_ANGLE * (((t->tm_hour % 12) * 6) + (t->tm_min / 10))) / (12 * 6));
gpath_draw_filled(ctx, s_hour_arrow);
gpath_draw_outline(ctx, s_hour_arrow);
// dot in the middle
graphics_context_set_fill_color(ctx, GColorBlack);
graphics_fill_rect(ctx, GRect(bounds.size.w / 2 - 1, bounds.size.h / 2 - 1, 3, 3), 0, GCornerNone);
}
static void date_update_proc(Layer *layer, GContext *ctx) {
time_t now = time(NULL);
struct tm *t = localtime(&now);
strftime(s_day_buffer, sizeof(s_day_buffer), "%a", t);
text_layer_set_text(s_day_label, s_day_buffer);
strftime(s_num_buffer, sizeof(s_num_buffer), "%d", t);
text_layer_set_text(s_num_label, s_num_buffer);
}
static void handle_second_tick(struct tm *tick_time, TimeUnits units_changed) {
layer_mark_dirty(window_get_root_layer(window));
}
static void window_load(Window *window) {
Layer *window_layer = window_get_root_layer(window);
GRect bounds = layer_get_bounds(window_layer);
// Create GBitmap, then set to created BitmapLayer
s_background_bitmap = gbitmap_create_with_resource(RESOURCE_ID_IMAGE_BACKGROUND);
s_background_layer = bitmap_layer_create(GRect(0, 0, 144, 168));
bitmap_layer_set_bitmap(s_background_layer, s_background_bitmap);
layer_add_child(window_get_root_layer(window), bitmap_layer_get_layer(s_background_layer));
s_date_layer = layer_create(bounds);
layer_set_update_proc(s_date_layer, date_update_proc);
layer_add_child(window_layer, s_date_layer);
s_day_label = text_layer_create(GRect(4, 146, 27, 20));
text_layer_set_text(s_day_label, s_day_buffer);
text_layer_set_background_color(s_day_label, GColorClear);
text_layer_set_text_color(s_day_label, GColorWhite);
text_layer_set_font(s_day_label, fonts_get_system_font(FONT_KEY_GOTHIC_18));
layer_add_child(s_date_layer, text_layer_get_layer(s_day_label));
s_num_label = text_layer_create(GRect(30, 146, 18, 20));
text_layer_set_text(s_num_label, s_num_buffer);
text_layer_set_background_color(s_num_label, GColorClear);
text_layer_set_text_color(s_num_label, GColorWhite);
text_layer_set_font(s_num_label, fonts_get_system_font(FONT_KEY_GOTHIC_18));
// Create temperature Layer
s_weather_label = text_layer_create(GRect(50, 146, 50, 20));
text_layer_set_text(s_weather_label, "Loading...");
text_layer_set_background_color(s_weather_label, GColorClear);
text_layer_set_text_color(s_weather_label, GColorWhite);
text_layer_set_font(s_weather_label, fonts_get_system_font(FONT_KEY_GOTHIC_18));
layer_add_child(s_date_layer, text_layer_get_layer(s_num_label));
s_hands_layer = layer_create(bounds);
layer_set_update_proc(s_hands_layer, hands_update_proc);
layer_add_child(window_layer, s_hands_layer);
}
static void window_unload(Window *window) {
// Destroy GBitmap
gbitmap_destroy(s_background_bitmap);
// Destroy BitmapLayer
bitmap_layer_destroy(s_background_layer);
layer_destroy(s_date_layer);
text_layer_destroy(s_day_label);
text_layer_destroy(s_num_label);
text_layer_destroy(s_weather_label);
layer_destroy(s_hands_layer);
}
static void init() {
window = window_create();
window_set_window_handlers(window, (WindowHandlers) {
.load = window_load,
.unload = window_unload,
});
window_stack_push(window, true);
s_day_buffer[0] = '\0';
s_num_buffer[0] = '\0';
// init hand paths
s_minute_arrow = gpath_create(&MINUTE_HAND_POINTS);
s_hour_arrow = gpath_create(&HOUR_HAND_POINTS);
Layer *window_layer = window_get_root_layer(window);
GRect bounds = layer_get_bounds(window_layer);
GPoint center = grect_center_point(&bounds);
gpath_move_to(s_minute_arrow, center);
gpath_move_to(s_hour_arrow, center);
for (int i = 0; i < NUM_CLOCK_TICKS; ++i) {
s_tick_paths[i] = gpath_create(&ANALOG_BG_POINTS[i]);
}
tick_timer_service_subscribe(SECOND_UNIT, handle_second_tick);
}
static void deinit() {
gpath_destroy(s_minute_arrow);
gpath_destroy(s_hour_arrow);
for (int i = 0; i < NUM_CLOCK_TICKS; ++i) {
gpath_destroy(s_tick_paths[i]);
}
tick_timer_service_unsubscribe();
window_destroy(window);
}
int main() {
init();
app_event_loop();
deinit();
}
答案 0 :(得分：2)
您需要将s_weather_label图层添加到其他图层。现在它已经创建但没有添加到任何东西。
我想只是添加：
layer_add_child(window_layer, text_layer_get_layer(s_weather_label));
会完全按照你的意愿行事！